Bifunctional degraders of interleukin-1 receptor-associated kinase and their therapeutic uses

Abstract

The present disclosure provides bifunctional compounds as degraders of IRAK4 via the ubiquitin-proteasome pathway, and methods for treating diseases modulated by IRAK4. The compounds of the present disclosure, or pharmaceutical compositions thereof, are useful as therapeutic agents for treating inflammatory disorders such as rheumatoid arthritis (RA), inflammatory bowel disease (IBD), Crohn's disease, ulcerative colitis, necrotizing enterocolitis, gout, Lyme disease, arthritis, psoriasis, pelvic inflammatory disease, systemic lupus erythematosus (SLE), Sjogren's syndrome, inflammation associated with gastrointestinal infections, including C. difficile, viral myocarditis, acute and chronic tissue injury, nonalcoholic steatohepatitis (NASH), alcoholic hepatitis, and kidney diseases, including chronic kidney disease and diabetic kidney disease.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Provisional Application No. 62 / 978,635, filed February 19, 2020, the entirety of which is incorporated herein by reference.

[0002] background Technical Field The present invention provides novel bifunctional compounds for the proteolytic degradation of interleukin-1 receptor-associated kinase 4 (IRAK4) and methods for treating diseases modulated by IRAK4. [Background technology]

[0003] 2. Description of Related Art Interleukin-1 receptor-associated kinase-4 (IRAK4) is a serine / threonine kinase that plays a key role in mediating Toll-like receptor (TLR) and interleukin-1 receptor (IL1R) signaling to produce proinflammatory cytokines in immune cells. IRAK4 functions as part of the midsome, a large multiprotein complex that assembles at the plasma membrane upon ligand binding to TLR and IL1R receptors. The first step in midsome assembly is the recruitment of the scaffolding protein MyD88, followed by IRAK4 binding to Myd88 via a homotypic death domain (DD) interaction. IRAK4 then undergoes autoactivation and subsequently phosphorylates the downstream kinases IRAK1 and IRAK2. Because IRAK4 is the most upstream kinase in this complex, it is considered a "master regulator" of midsome signaling. The importance of IRAK4 kinase function was demonstrated in IRAK4 kinase-dead mice, which are resistant to TLR-induced septic shock due to the inability of IRAK4 kinase to produce proinflammatory cytokines.

[0004] IRAK4 also reportedly possesses kinase-independent scaffolding functions. For example, macrophages derived from IRAK4 kinase-dead mice can still activate NF-κb signaling upon stimulation with IL-1, TLR2, TLR4, and TLR7. A similar scaffolding function has been demonstrated in human fibroblasts, where kinase-dead IRAK4 can restore IL-1-induced NF-κb signaling to levels comparable to those of wild-type IRAK4.

[0005] Therefore, IRAK4 can be targeted for degradation, which can provide therapeutic opportunities for the treatment of autoimmune, inflammatory, and oncological diseases.Specific degradation of IRAK4 can be achieved by using heterobifunctional small molecules to recruit IRAK4 to ubiquitin ligase, thereby promoting the ubiquitination and proteasomal degradation of IRAK4.For example, thalidomide derivatives such as lenalidomide or pomalidomide have been reported to recruit potential protein substrates to cereblon (CRBN), a component of the ubiquitin ligase complex.See, for example, WO2019 / 099926, WO2020 / 023851, and U.S. Published Application No. 2019 / 0192668. There is a need to further develop therapeutic agents that target IRAK4. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2019 / 099926 [Patent Document 2] International Publication No. 2020 / 023851 [Patent Document 3] U.S. Patent Publication No. 2019 / 0192668 Summary of the Invention [Means for solving the problem]

[0007] Quick summary Bifunctional compounds represented by formula (I) [ka] or a pharmaceutically acceptable salt, isotopic form, isolated stereoisomer or mixture of stereoisomers thereof, wherein R 1 is 1 to 3 R a C being replaced as needed by 1~10 Alkyl; 1 to 3 R a C being replaced as needed by 3~10 cycloalkyl; or 1 to 3 R a is a 3- to 12-membered heterocyclyl optionally substituted by L is -L1-L2-L3-L4-L5-, where L1, L2, L3, L4 and L5 are each independently: a) 1 to 3 R b C being replaced as needed by 3~12 cycloalkyl; b) 1 to 3 R b C being replaced as needed by 6~12 aryl; c) 1 to 3 R b 3-12 membered heterocyclyl optionally substituted by; d) 1 to 3 R b 5-12 membered heteroaryl optionally substituted by e) direct binding; f) 1 to 3 R d C being replaced as needed by 1~12 Alkylene chain; g) 1 to 3 R d C being replaced as needed by 2~12 Alkenylene chain; h) 1 to 3 R d C being replaced as needed by 2~12 Alkynylene chain; i) 1 to 6 ethylene glycol units; j) 1 to 6 propylene glycol units; or k) -C(O)-, -C(O)O-, -O- 、 -N(R c )-, -S-, -C(S)-, -C(S)-O-, -S(O)2-, -S(O)=N-, -S(O)2NH-, -C(O)-N(R c )-, -C=N-, -OC(O)-N(R c )-, -, or -OC(O)-O-; and; LHM is the ligase harness moiety; R a each independently represents a halo, -CN, or one to three R d C being replaced as needed by 1~3 Alkyl, 1 to 3 R d C being replaced as needed by 3~6 Cycloalkyl or -OR c and; R b each independently represents oxo, imino, sulfoximino, halo, nitro, -CN, C 1~6 Alkyl, C 2~6 Alkenyl, C 2~6 Alkynyl, C 3~15 Cycloalkyl, C 1~8 Haloalkyl, C 6~12 Aryl, 5-12 membered heteroaryl, 3-12 membered heterocyclyl, -OR c , -C(O)-R c , -C(O)OR c , -C(O)-N(R c )(R c ), -N(R c )(R c ), -N(R c )C(O)-R c , -N(R c )C(O)OR c , -N(R c )C(O)N(R c )(R c ), -N(R c )S(O)2(R c ), -NR c S(O)2N(Rc )(R c ), -N(R c )S(O)2O(R c ), -OC(O)R c , -OC(O)-N(R c )(R c ), -Si(R c )3, -SR c , -S(O)R c , -S(O)(NH)R c , -S(O)2R c or -S(O)N(R c )(R c ) and C 1~6 Alkyl, C 2~6 Alkenyl, C 2~6 Alkynyl, C 3~15 Cycloalkyl, C 1~8 Haloalkyl, C 6~12 Aryl, 5- to 12-membered heteroaryl, and 3- to 12-membered heterocyclyl each have 1 to 3 R d may be optionally substituted by; R c are each independently hydrogen or C 1~6 is alkyl; R d each independently represents C optionally substituted with halo, oxo, —CN, —OH, or 1 to 3 fluoro; 1~6 Alkyl, or C 3~8 -OC optionally substituted with cycloalkyl or 1 to 3 fluoro 1~6 alkyl) is provided herein.

[0008] In various further embodiments, the LHM targets the E3 ligases VHL, CRBN, or IAP, which are utilized by the bifunctional compound to induce ubiquitination of IRAK4 and its subsequent proteasomal degradation.

[0009] In more specific embodiments, the LHM is represented by formula (IIA), (IIB), (IIIA), (IIIB), (IIIC), (IIID), (IIIE), (IVA), (IVB), (IVC) or (IVD), or individual substructures thereof.

[0010] In more particular embodiments, the bifunctional compounds are Examples 1-192 described in the Examples.

[0011] A further embodiment provides a pharmaceutical composition comprising a compound of formula (I) or any one of its substructures, and a pharmaceutically acceptable carrier.

[0012] In certain embodiments, the compounds of formula (I) or pharmaceutical compositions thereof are useful as therapeutic agents for treating cancers such as lymphoma, leukemia, acute myeloid leukemia (AML), and myelodysplastic syndromes (MDS).

[0013] In other embodiments, the compounds of formula (I) or pharmaceutical compositions thereof are useful as therapeutic agents for treating metabolic disorders such as diabetes (type I and type II diabetes), metabolic syndrome, dyslipidemia, obesity, glucose intolerance, hypertension, elevated serum cholesterol, and elevated triglycerides.

[0014] In other embodiments, the compounds of formula (I) or pharmaceutical compositions thereof are useful as therapeutic agents for treating inflammatory disorders such as rheumatoid arthritis (RA), inflammatory bowel disease (IBD), Crohn's disease, ulcerative colitis, necrotizing enterocolitis, gout, Lyme disease, arthritis, psoriasis, pelvic inflammatory disease, systemic lupus erythematosus (SLE), Sjogren's syndrome, inflammation associated with gastrointestinal infections including C. difficile, viral myocarditis, acute and chronic tissue injury, nonalcoholic steatohepatitis (NASH), alcoholic hepatitis, and kidney diseases including chronic kidney disease and diabetic kidney disease. DETAILED DESCRIPTION OF THE INVENTION

[0015] Detailed Description Bifunctional compounds capable of recruiting IRAK4 to E3 ubiquitin ligase for degradation, as well as methods for preparing and using the same are disclosed. In particular, the bifunctional compounds typically comprise an IRAK4 binding moiety covalently conjugated via a linker to a ligase harness moiety for targeting the ubiquitin ligase. Advantages In particular, targeted degradation of IRAK4 provides effective treatment or amelioration of disease states, including IRAK4 function.

[0016] One embodiment is a bifunctional compound of formula (I) [ka] or a pharmaceutically acceptable salt, isotopic form, isolated stereoisomer or mixture of stereoisomers thereof, wherein R 1 is 1 to 3 R a C being replaced as needed by 1~10 Alkyl; 1 to 3 R a C being replaced as needed by 3~10 cycloalkyl; or 1 to 3 R a is a 3- to 12-membered heterocyclyl optionally substituted by L is -L1-L2-L3-L4-L5-, where L1, L2, L3, L4 and L5 are each independently: a) 1 to 3 R b C being replaced as needed by 3~12 cycloalkyl; b) 1 to 3 R b C being replaced as needed by 6~12 aryl; c) 1 to 3 R b 3-12 membered heterocyclyl optionally substituted by; d) 1 to 3 R b 5-12 membered heteroaryl optionally substituted by e) direct binding; f) 1 to 3 R dC being replaced as needed by 1~12 Alkylene chain; g) 1 to 3 R d C being replaced as needed by 2~12 Alkenylene chain; h) 1 to 3 R d C being replaced as needed by 2~12 Alkynylene chain; i) 1 to 6 ethylene glycol units; j) 1 to 6 propylene glycol units; k) -C(O)-, -C(O)O-, -O- 、 -N(R c )-, -S-, -C(S)-, -C(S)-O-, -S(O)2-, -S(O)=N-, -S(O)2NH-, -C(O)-N(R c )-, -C=N-, -OC(O)-N(R c )-, -, or -OC(O)-O-; and; LHM is the ligase harness moiety; R a each independently represents a halo, -CN, or one to three R d C being replaced as needed by 1~3 Alkyl, 1 to 3 R d C being replaced as needed by 3~6 Cycloalkyl or -OR c and; R b each independently represents oxo, imino, sulfoximino, halo, nitro, -CN, C 1~6 Alkyl, C 2~6 Alkenyl, C 2~6 Alkynyl, C 3~15 Cycloalkyl, C 1~8 Haloalkyl, C 6~12 Aryl, 5-12 membered heteroaryl, 3-12 membered heterocyclyl, -OR c , -C(O)-R c , -C(O)OR c , -C(O)-N(R c )(R c ), -N(R c )(Rc ), -N(R c )C(O)-R c , -N(R c )C(O)OR c , -N(R c )C(O)N(R c )(R c ), -N(R c )S(O)2(R c ), -NR c S(O)2N(R c )(R c ), -N(R c )S(O)2O(R c ), -OC(O)R c , -OC(O)-N(R c )(R c ), -Si(R c )3, -SR c , -S(O)R c , -S(O)(NH)R c , -S(O)2R c or -S(O)N(R c )(R c ) and C 1~6 Alkyl, C 2~6 Alkenyl, C 2~6 Alkynyl, C 3~15 Cycloalkyl, C 1~8 Haloalkyl, C 6~12 Aryl, 5- to 12-membered heteroaryl, and 3- to 12-membered heterocyclyl each have 1 to 3 R d may be optionally substituted by; R c are each independently hydrogen or C 1~6 is alkyl; R d each independently represents C optionally substituted with halo, oxo, —CN, —OH, or 1 to 3 fluoro; 1~6 Alkyl, or C 3~8 -OC optionally substituted with cycloalkyl or 1 to 3 fluoro 1~6 alkyl) to provide. IRAK4 binding site

[0017] The IRAK4 binding portion of the bifunctional compound of Formula (I) has the following structure, where the wavy line indicates the bond connecting it to the remainder of the compound of Formula (I): [ka] (In the formula, R 1 is 1 to 3 R a C being replaced as needed by 1~10 Alkyl; 1 to 3 R a C being replaced as needed by 3~10 cycloalkyl; or 1 to 3 R a is a 3- to 12-membered heterocyclyl optionally substituted by In more particular embodiments, R 1 teeth a) C optionally substituted with halo, -OH or -CN 1~5 alkyl; b) Halo, C 1~5 4- to 8-membered heterocyclyl optionally substituted with alkyl, —OH, or —CN; or c) Halo, C 1~5 C optionally substituted with alkyl, -OH, or -CN 3~10 cycloalkyl; is.

[0018] In more particular embodiments, R 1 are oxetane, tetrahydrofuran, or tetrahydropyran, each of which is F, C 1~3 It may be optionally substituted with alkyl, -OH or -CN.

[0019] In other more particular embodiments, [ka] The moiety has one of the following structures (the wavy line indicates the bond attached to the thiadiazole moiety): [ka] It has. Ligase harness part (LHM)

[0020] The von Hippel-Lindau (VHL) and cereblon (CRBN) proteins are substrate-recognition subunits of two ubiquitously expressed and biologically important Cullin-type RING E3 ubiquitin ligase complexes. Furthermore, the inhibitor of apoptosis proteins (IAPs) are a family of proteins involved in the suppression of apoptosis. The human IAP family contains eight members, and numerous other organisms contain IAP homologs. IAPs contain an E3 ligase-specific domain and a baculovirus IAP repeat (BIR) domain that recognize substrates and promote their ubiquitination.

[0021] The LHM of compounds of formula (I) targets the E3 ligases VHL, CRBN or IAP, which are utilized by the bifunctional compounds to induce ubiquitination of IRAK4 and its subsequent proteasomal degradation. A. LHM targeting CRBN

[0022] Thalidomide derivatives such as lenalidomide or pomalidomide can be used to recruit potential substrates to CRBN, a component of the ubiquitin ligase complex.

[0023] One embodiment has the following structure: [ka] (In the formula, W is -C(R g )- or -N-; Y is a direct bond, C 1~4 Alkylene chain, -C(O)-, -C(O)O-, -O-, -N(R g )-, -S--C(S)-, -C(S)-O-, -OC(O)O-, -C(O)-N(R g )-, -OC(O)-N(R g)-and; The B ring is C 6~12 aryl, 5- to 12-membered heteroaryl, or 3- to 12-membered heterocyclyl, each of which is selected from 1 to 3 R j and R j each independently represents oxo, imino, sulfoximino, halo, nitro, -CN, C 1~6 Alkyl, C 2~6 Alkenyl, C 2~6 Alkynyl, C 3~15 Cycloalkyl, C 1~8 Haloalkyl, C 6~12 Aryl, 5-12 membered heteroaryl, 3-12 membered heterocyclyl, -OR g , -C(O)-R g , -C(O)OR g , -C(O)-N(R g )(R g ), -N(R g )(R g ), -N(R g )C(O)-R g , -N(R g )C(O)OR g , -N(R g )C(O)N(R g )(R g ), -N(R g )S(O)2(R g ), -NR g S(O)2N(R g )(R g ), -N(R g )S(O)2O(R g ), -OC(O)R g , -OC(O)-N(R g )(R g ), -Si(R g )3, -SR g , -S(O)R g , -S(O)(NH)R g , -S(O)2R g or -S(O)N(R g )(R g ) and C 1~6 Alkyl, C 2~6 Alkenyl, C 2~6Alkynyl, C 3~15 Cycloalkyl, C 1~8 Haloalkyl, C 6~12 Aryl, 5- to 12-membered heteroaryl, and 3- to 12-membered heterocyclyl each have 1 to 3 R k may be optionally substituted by; R g is hydrogen or C 1~6 is alkyl; R k each independently represents C optionally substituted with halo, oxo, —CN, —OH, or 1 to 3 fluoro; 1~6 Alkyl, or C 3~8 -OC optionally substituted with cycloalkyl or 1 to 3 fluoro 1~6 alkyl) (The wavy line indicates the bond connecting to the remainder of the compound of formula (I)).

[0024] In certain particular embodiments, Y is a direct bond and Formula (IIA) has the following structure: [ka] (In the formula, W is -C(R g )- or -N-; Z1 is -C(O)-, -C(S)-, -C(NR g )-, -C(R g )2-, -N=, -N(R g )-, -C(R g )2-C(O)-, -C(O)-N(R g )-, -CR g =CR g -, -C(R g )2-C(S)-, -C(R g )=N- or -C(R g )2-C(R g )2- and; Z2 is -C(O)--, -C(S)--, -C(NR g )-, -N(R g)-, -N= or -C(R g )2- and; R g is hydrogen or C 1~6 is alkyl; The E ring is phenyl, 5- to 6-membered heteroaryl, or 5- to 6-membered heterocyclyl, each of which is selected from 1 to 3 R j (replaced as necessary by It has.

[0025] In a more particular embodiment, Z2 is -C(O)- and formula (IIA1) has the following structure: [ka] (In the formula, W is -C(R g )- or -N-; Z1 is -C(O)-, -C(S)-, -C(NR g )-, -C(R g )2-, -C(R g )2-C(O)-, -C(O)-N(R g )-, -CR g =CR g -, -C(R g )=N-, -C(R g )2-C(S)- or -C(R g )2-C(R g )2- and; q is 0, 1 or 2; R g is hydrogen or C 1~6 is alkyl; R 2 is C 1~6 Alkyl, Halo, HaloC 1~6 Alkyl, -N(R g )2, CN, nitro, hydroxyl or -OC 1~4 alkyl) It has.

[0026] In an even more particular embodiment of formula (IIA1′), W is —CH—; and Z 1 is —C(O)—, —CH 2 —, —CH 2 —C(O)—, or —CH═CH—.

[0027] In certain embodiments, formula (IIA1′) has one of the following structures: [ka] It has. In other embodiments, Formula (IIA) has the following structure: [ka] (In the formula, W is -C(R g )- or -N-; Z3 is -C(O)-, -C(S)-, -C(NR g )-, -C(R g )2-, -N=, -N(R g )-, -C(R g )2-C(O)-, -C(O)-N(R g )-, -CR g =CR g -, -C(R g )2-C(S)-, -C(R g )=N-, -C(R g )2-C(R g )2-, -C(R g )2-O-, -C(R g )2-S-, -O- or -S-; Z4 is -C(O)--, -C(S)--, -C(NR g )-, -N(R g )-, -N=, -O-, -S- or -C(R g )2- and; R g is hydrogen or C 1~6 is alkyl; The E ring is phenyl, 5- to 6-membered heteroaryl, or 5- to 6-membered heterocyclyl, each of which is selected from 1 to 3 R j (replaced as necessary by It has.

[0028] In a more particular embodiment of formula (IIA2), W is -CtH-; Z3 is -C(R g )2-, -N(R g )-, -C(R g )2-C(O)-, -C(O)-N(R g )-, -CR g =CR g -, -C(R g )2-C(S)-, -C(R g )=N-, -C(R g )2-C(R g )2-, -C(R g )2-O or -C(R g )2-S-; Z4 is -C(O)-, -C(S)-, -C(NR g )- or -C(R g )2-.

[0029] In yet other more particular embodiments, formula (IIA2) has the following structure: [ka] (wherein q is 0, 1, or 2; R g is hydrogen or C 1~6 alkyl; R 2 is C 1~6 Alkyl, Halo, HaloC 1~6 Alkyl, -N(R g )2, CN, nitro, hydroxyl or -OC 1~4 alkyl) It has.

[0030] In a more particular embodiment, formula (IIA2') has the following structure: [ka] It has.

[0031] In a more particular embodiment of formula (IIA), W is —CH—; Y is a direct bond, C1~4 Alkylene chain, -C(O)-, -C(O)O-, -O-, -N(R g )-, -S-, -C(S)-, -C(S)-O-, -OC(O)O-, -C(O)-N(R g )-, -OC(O)-N(R g )-; and B ring is phenyl, 5-6 membered heteroaryl, or 5-6 membered heterocyclyl, each of which is selected from 1-3 R j are substituted as necessary by

[0032] In certain embodiments, formula (IIA) has one of the following structures: [ka] It has.

[0033] In another embodiment, the LHM that targets CRBN has the following structure: [ka] (In the formula, W is -C(R g )- or -N-; The D ring is phenyl, 5- to 6-membered heteroaryl, or 5- to 6-membered heterocyclyl, each of which is selected from 1 to 3 R j and The B ring is C 6~12 aryl, 5- to 12-membered heteroaryl, or 3- to 12-membered heterocyclyl, each of which is selected from 1 to 3 R j and R g is hydrogen or C 1~6 is alkyl; R j each independently represents oxo, imino, sulfoximino, halo, nitro, -CN, C 1~6 Alkyl, C 2~6 Alkenyl, C 2~6 Alkynyl, C 3~15 Cycloalkyl, C 1~8Haloalkyl, C 6~12 Aryl, 5-12 membered heteroaryl, 3-12 membered heterocyclyl, -OR g , -C(O)-R g , -C(O)OR g , -C(O)-N(R g )(R g ), -N(R g )(R g ), -N(R g )C(O)-R g , -N(R g )C(O)OR g , -N(R g )C(O)N(R g )(R g ), -N(R g )S(O)2(R g ), -NR g S(O)2N(R g )(R g ), -N(R g )S(O)2O(R g ), -OC(O)R g , -OC(O)-N(R g )(R g ), -Si(R g )3, -SR g , -S(O)R g , -S(O)(NH)R g , -S(O)2R g or -S(O)N(R g )(R g ) and C 1~6 Alkyl, C 2~6 Alkenyl, C 2~6 Alkynyl, C 3~15 Cycloalkyl, C 1~8 Haloalkyl, C 6~12 Aryl, 5- to 12-membered heteroaryl, and 3- to 12-membered heterocyclyl each have 1 to 3 R k may be optionally substituted by; R k each independently represents C optionally substituted with halo, oxo, —CN, —OH, or 1 to 3 fluoro; 1~6 Alkyl, or C 3~8-OC optionally substituted with cycloalkyl or 1 to 3 fluoro 1~6 alkyl) It has.

[0034] In more particular embodiments, formula (IIB) has the following structure: [ka] (In the formula, Z5 is -C(O)-, -C(S)-, -C(NR g )-, -N(R g )-, -N= or -C(R g )2- and; Z6 is -C(O)-, -C(S)-, -C(NR g )-, -C(R g )2-, -N=, -N(R g )-, -C(R g )2-C(O)-, -C(O)-N(R g )-, -CR g =CR g -, -C(R g )2-C(S)-, -C(R g )=N- or -C(R g )2-C(R g )2- and; Z7 is -C(O)--, -C(S)--, -C(NR g )-, -N(R g )-, -O-, -S-, -N= or -C(R g )2- and; R g is hydrogen or C 1~6 alkyl) It has. In an even more particular embodiment, formula (IIB1) has the following structure: [ka] It has.

[0035] More particularly, formula (IB1′) has the following structure: [ka] (wherein q is 0, 1, or 2; R 2 is C 1~6 Alkyl, Halo, HaloC 1~6 Alkyl, -N(R g )2, CN, nitro, hydroxyl or -OC 1~4 alkyl) It has.

[0036] In a more particular embodiment, formula (IB1′) has the following structure: [ka] It has. B. VHL-targeted LHM

[0037] In various embodiments, the LHM that targets von Hippel-Lindau (VHL) ligase has one of the following structures (the wavy line indicates the bond connecting to the remainder of the compound of Formula (I): [ka] (In the formula, V1 is -C(O)-, -C(O)O-, -C(O)O--C(R e )2-, -C(O)-N(R e )-, -C(O)--C(R e )2- or -C(O)-N(R e )-C(R e )2- and; V2 is -C(O)-C(R e )2- and; The G ring is phenyl, 5- to 6-membered heteroaryl, or 5- to 6-membered heterocyclyl, each of which is selected from 1 to 3 R j being replaced as necessary by; The J rings are 5-12 membered heteroaryl or 5-12 membered heterocyclyl, each of which is selected from 1-3 R j and R e are each independently hydrogen, C 1~6 Alkyl or C 3~8 is cycloalkyl; R j each independently represents oxo, imino, sulfoximino, halo, nitro, -CN, C 1~6 Alkyl, C 2~6 Alkenyl, C 2~6 Alkynyl, C 3~15 Cycloalkyl, C 1~8 Haloalkyl, C 6~12 Aryl, 5-12 membered heteroaryl, 3-12 membered heterocyclyl, -OR g , -C(O)-R g , -C(O)OR g , -C(O)-N(R g )(R g ), -N(R g )(R g ), -N(R g )C(O)-R g , -N(R g )C(O)OR g , -N(R g )C(O)N(R g )(R g ), -N(R g )S(O)2(R g ), -NR g S(O)2N(R g )(R g ), -N(R g )S(O)2O(R g ), -OC(O)R g , -OC(O)-N(R g )(R g ), -Si(R g )3, -SR g , -S(O)R g , -S(O)(NH)R g , -S(O)2R g or -S(O)N(R g )(R g ) and C 1~6 Alkyl, C 2~6 Alkenyl, C 2~6 Alkynyl, C 3~15 Cycloalkyl, C1~8 Haloalkyl, C 6~12 Aryl, 5- to 12-membered heteroaryl, and 3- to 12-membered heterocyclyl each have 1 to 3 R k may be optionally substituted by; R g are each independently hydrogen or C 1~6 is alkyl; R k each independently represents C optionally substituted with halo, oxo, —CN, —OH, or 1 to 3 fluoro; 1~6 Alkyl, or C 3~8 -OC optionally substituted with cycloalkyl or 1 to 3 fluoro 1~6 is alkyl; R 3 is hydrogen or hydroxyl; R 4 is -C(O)R f and R f is C 1~6 Alkyl or C 3~8 cycloalkyl, each of which is optionally substituted with halo or —CN. It has.

[0038] In more specific embodiments, formulas (IIIA), (IIIB), (IIIC), (IIID), and (IIIE) have the structures of formulas (IIIA1), (IIIB1), (IIIC1), (IIID1), and (IIIE1), respectively: [ka] (In the formula, p is 0 or 1; R j is 1 to 3 R k is a 5-6 membered heteroaryl optionally substituted by R k are each independently halo, oxo, -CN, -OH, C 1~6 Alkyl, C 3~8 Cycloalkyl or -OC 1~6is alkyl; R e are each independently hydrogen, C 1~6 Alkyl or C 3~8 is cycloalkyl; R g are each independently hydrogen or C 1~6 is alkyl; R 3 is hydrogen or hydroxyl; R 4 is -C(O)R f and R f is C 1~6 Alkyl or C 3~8 cycloalkyl, each of which is optionally substituted with halo or —CN. It has.

[0039] In certain more particular embodiments of any one of formulas (IIIA1), (IIIB1), (IIIC1), (IIID1) or (IIIE1), p is 1 and R j are thiazolyl, oxazolyl, isoxazolyl, pyrazolyl, imidazolyl, 1,2,4-oxadiazolyl, and 1,3,4-oxadiazolyl, respectively, 1~6 Alkyl, C 3~8 Optionally substituted with cycloalkyl, halo, CN, haloalkyl, or hydroxyalkyl.

[0040] In a preferred embodiment, R j is thiazolyl optionally substituted with alkyl (eg methyl).

[0041] Thus, a more particular embodiment of formula (IIIA) has the following structure: [ka] It has.

[0042] More particular embodiments of formula (IIIB) or (IIIB1) have one of the following structures: [ka] It has.

[0043] More particular embodiments of formula (IIIC) or (IIIC1) have one of the following structures: [ka] It has.

[0044] More particular embodiments of formula (IIID) or formula (IIID1) have one of the following structures: [ka] It has.

[0045] More particular embodiments of formula (IIIE) or (IIIE1) have one of the following structures: [ka] It has.

[0046] In other embodiments, the thiazolyl may be absent (i.e., p is 0). These des-thiazolyl LHMs can still bind to VHL sufficiently to induce degradation. More particularly, formula (IIIA), (IIIB), (IIIC) or (IIID) has one of the following structures: [ka] It has. C. LHM targeting IAPs

[0047] In various embodiments, the LHM that targets von Hippel-Lindau (VHL) ligase has one of the following structures (the wavy line indicates the bond connecting to the remainder of the compound of Formula (I): [ka] (In the formula, R 5 are each independently hydrogen or C 1~6 is alkyl; R 6 are each independently hydrogen or C 1~6 is alkyl; R 7 are each independently hydrogen, C 1~6 Alkyl or C 3~8 is cycloalkyl; R 8 are each independently aryl, 5- to 12-membered cycloalkyl, 5- to 12-membered heteroaryl, or 5- to 12-membered heterocyclyl, and each is selected from 1 to 3 R j and R 9 each independently represents hydrogen, halo, or C 1~6 is alkyl; R j each independently represents oxo, imino, sulfoximino, halo, nitro, -CN, C 1~6 Alkyl, C 2~6 Alkenyl, C 2~6 Alkynyl, C 3~15 Cycloalkyl, C 1~8 Haloalkyl, C 6~12 Aryl, 5-12 membered heteroaryl, 3-12 membered heterocyclyl, -OR g , -C(O)-R g , -C(O)OR g , -C(O)-N(R g )(R g ), -N(R g )(R g ), -N(R g )C(O)-R g , -N(R g )C(O)OR g , -N(R g )C(O)N(R g )(R g ), -N(R g)S(O)2(R g ), -NR g S(O)2N(R g )(R g ), -N(R g )S(O)2O(R g ), -OC(O)R g , -OC(O)-N(R g )(R g ), -Si(R g )3, -SR g , -S(O)R g , -S(O)(NH)R g , -S(O)2R g or -S(O)N(R g )(R g ) and C 1~6 Alkyl, C 2~6 Alkenyl, C 2~6 Alkynyl, C 3~15 Cycloalkyl, C 1~8 Haloalkyl, C 6~12 Aryl, 5- to 12-membered heteroaryl, and 3- to 12-membered heterocyclyl each have 1 to 3 R k may be optionally substituted by; R g are each independently hydrogen or C 1~6 is alkyl; R k each independently represents C optionally substituted with halo, oxo, —CN, —OH, or 1 to 3 fluoro; 1~6 Alkyl, or C 3~8 -OC optionally substituted with cycloalkyl or 1 to 3 fluoro 1~6 is alkyl; U1 is a direct bond or -C(O)-; Z is -CH- or N; The K ring is phenyl or naphthyl. It has. More particular embodiments of formulae (IVA), (IVB), (IVC) and (IVD) each have the following structure: [ka] It has. Linker

[0048] The bifunctional compound of formula (I) comprises a linker moiety that connects the IRAK4 binding moiety to the LHM. The structure (e.g., length or rigidity) of the linker moiety can affect the efficiency or selectivity of the degradation process. Typically, the linker moiety comprises multiple segments that provide individual attachment points to the IRAK4 binding moiety and the LHM, as well as contributing to the overall length and rigidity of the linker.

[0049] In certain embodiments, the linker moiety (L) of formula (I) comprises up to five linker segments (L s and s is 1 to 5), and the compounds of formula (I) have the following structure: [ka] (wherein L1, L2, L3, L4 and L5 each independently represent the following: a) 1 to 3 R b C being replaced as needed by 3~10 cycloalkyl; b) 1 to 3 R b aryl optionally substituted by c) 1 to 3 R b 3-12 membered heterocyclyl optionally substituted by; d) 1 to 3 R b 5-12 membered heteroaryl optionally substituted by e) direct binding; f) 1 to 3 R d C being replaced as needed by 1~12 Alkylene chain; g) 1 to 3 R d C being replaced as needed by 2~12 Alkenylene chain; h) R1-3 d C being replaced as needed by 2~12Alkynylene chain; i) 1 to 6 ethylene glycol units; j) 1 to 6 propylene glycol units; and k) -C(O)-, -C(O)O-, -O- 、 -N(R c )-, -S-, -C(S)-, -C(S)-O-, -S(O)2-, -S(O)=N-, -S(O)2NH-, -C(O)-N(R c )-, -C=N-, -OC(O)-N(R c )-, -, or -OC(O)-O-; is a divalent moiety selected from: R b each independently represents oxo, imino, sulfoximino, halo, nitro, -CN, C 1~6 Alkyl, C 2~6 Alkenyl, C 2~6 Alkynyl, C 3~15 Cycloalkyl, C 1~8 Haloalkyl, C 6~12 Aryl, 5-12 membered heteroaryl, 3-12 membered heterocyclyl, -OR c , -C(O)-R c , -C(O)OR c , -C(O)-N(R c )(R c ), -N(R c )(R c ), -N(R c )C(O)-R c , -N(R c )C(O)OR c , -N(R c )C(O)N(R c )(R c ), -N(R c )S(O)2(R c ), -NR c S(O)2N(R c )(R c ), -N(R c )S(O)2O(R c ), -OC(O)R c , -OC(O)-N(R c )(R c ), -Si(R c )3, -SRc , -S(O)R c , -S(O)(NH)R c , -S(O)2R c or -S(O)N(R c )(R c ) and C 1~6 Alkyl, C 2~6 Alkenyl, C 2~6 Alkynyl, C 3~15 Cycloalkyl, C 1~8 Haloalkyl, C 6~12 Aryl, 5- to 12-membered heteroaryl, and 3- to 12-membered heterocyclyl each have 1 to 3 R d may be optionally substituted by; R c are each independently hydrogen or C 1~6 is alkyl; R d each independently represents C optionally substituted with halo, oxo, —CN, —OH, or 1 to 3 fluoro; 1~6 C optionally substituted with alkyl or 1 to 3 fluoro 3~8 cycloalkyl) It has.

[0050] Unless otherwise specified, and provided that valency is satisfied, any divalent moiety described herein (e.g., L or L s ) are not limited to the orientation in which they are depicted. For example, for a given linker segment, e.g., -C(O)-NH-, the manner in which it is attached to the rest of the molecule can be in either orientation: i.e., -C(O)-NH or -NH-C(O)-, provided that the attachment does not violate the valency rules.

[0051] On the other hand, if L is a set of L s When represented by the formula (I'), the directionality is determined by the designated L sFor example, it should be understood that linker segment L1 directly connects to the IRAK4 binding moiety, while linker segment L5 directly connects to the LHM.

[0052] One or more linker segments may be a direct bond, for example, in -L2-L3-L4--, when L3 is a direct bond, L2 and L4 are directly bonded to each other, and L3 is substantially absent.

[0053] In various particular embodiments, L is C 3~15 Cycloalkyl; a ring selected from 6- to 15-membered aryl, 3- to 15-membered heterocyclyl, and 5- to 15-membered heteroaryl, each of which may be joined by up to three R d (as defined herein). In a more particular embodiment, L is C 3~12 Cycloalkyl; a ring selected from 6- to 12-membered aryl, 3- to 12-membered heterocyclyl, and 5- to 12-membered heteroaryl, each of which may be joined by up to three R d (as defined herein).

[0054] In various particular embodiments, L is one of the following ring moieties: [ka] and each ring may be one to three R d and R d are independently halo, oxo, -CN, -OH, C 1~6 Alkyl, C optionally substituted with 1 to 3 fluoro 3~8 -OC optionally substituted with cycloalkyl or 1 to 3 fluoro 1~6 It is alkyl.

[0055] In more particular embodiments, L1 has one of the following structures: [ka] It has.

[0056] In a preferred embodiment, L1 has one of the following structures: [ka] It has.

[0057] In further embodiments, -L2-L3-L4-L5- has a generally linear structure (i.e., not a ring). More particularly, -L2-L3-L4-L5- can be any of -C(O)-, -NH-C(O)-, -C(O)-(CH2) n -, -C(O)-(CH2) n -C(O)-, -C(O)-(CH2) n -O-, -(CH2) n -, -C(O)-(CH2) n -NH-, -C(O)-(CH2CH2O) m -, -C(O)-(CH2CH2O) m -(CH2) n -C(O)-, -C(O)-(CH2CH2O) m -(CH2) n -NH-, -C(O)-(CH2CH2O) m -(CH2) n -, -NH-C(O)-(CH2CH2O) m -(CH2) n -C(O)-, -NH-C(O)-(CH2CHO) m -(CH2) n -NH-, -NH-C(O)-(CH2) n -C(O)-, -NH-C(O)-(CH2) n -, -NH-C(O)-(CH2CH2O) m -, -NH-C(O)-(CH2) n -O-, -NH-C(O)-(CH2) n -NH- or -NH-C(O)-(CH2CH2O)m -(CH2) n -, m and n are independently integers from 1 to 12, and one or two hydrogens in each of the linker moieties can be C 1~3 It may be substituted by alkyl (eg methyl, ethyl, n-propyl or isopropyl).

[0058] In preferred embodiments, m is an integer from 1 to 10; and n is an integer from 1 to 10. In other embodiments, m is 1, 2, 3, 4, 5, or 6, and n is 1, 2, or 3. In various preferred embodiments, m is 1, 2, 3, 4, 5, or 6. In various preferred embodiments, n is 3, 4, 5, 6, 7, 8, 9, or 10.

[0059] In certain embodiments, L1 is [ka] and L has the following structure: [ka] In preferred embodiments, m is 1, 2, 3, 4, 5, or 6, and n is 1, 2, 3, 4, 5, or 6. In more preferred embodiments, m is 1, 2, or 3, and n is 1 or 2.

[0060] In other embodiments, L1 is [ka] and L has the following structure: [ka] In preferred embodiments, m is 1, 2, 3, 4, 5, or 6, and n is 2, 4, or 6. In even more preferred embodiments, m is 1, 2, or 3, and n is 2.

[0061] In other embodiments, L1 is [ka] and L has the following structure: [ka] In preferred embodiments, m is 1, 2, 3, 4, 5, or 6, and n is 2, 4, or 6. In even more preferred embodiments, m is 1, 2, or 3, and n is 2.

[0062] In other embodiments, L1 is [ka] and L has the following structure: [ka] In preferred embodiments, m is 1, 2, 3, 4, 5, or 6. In even more preferred embodiments, m is 1, 2, or 3.

[0063] In other embodiments, L1 is [ka] and L has the following structure: [ka] In preferred embodiments, n is 1, 2, 3, 4, 5, 6, 7, or 8. In even more preferred embodiments, n is 2, 3, 4, or 5.

[0064] In other embodiments, L1 is [ka] and L has the following structure: [ka] In preferred embodiments, n is 1, 2, 3, 4, 5, or 6. In even more preferred embodiments, n is 1, 3, or 5.

[0065] In other embodiments, L1 is [ka] and L has the following structure: [ka] In preferred embodiments, n is 4, 5, 6, 7, or 8. In even more preferred embodiments, n is 5 or 7.

[0066] In other embodiments, L1 is [ka] and L is one of the following structures: [ka] (In the formula, R c is hydrogen or C 1~3 In preferred embodiments, n is 1, 2, 3, or 4. In even more preferred embodiments, n is 1 or 2.

[0067] In other embodiments, L1 is [ka] and L has the following structure: [ka] In preferred embodiments, n is 1, 2, 3, 4, 5, 6, 7, or 8. In even more preferred embodiments, n is 1, 5, or 7.

[0068] In other embodiments, L1 is [ka] and L has the following structure: [ka] In preferred embodiments, m is 1, 2, 3, 4, 5, or 6, and n is 2, 4, or 6. In even more preferred embodiments, m is 1, 2, or 3, and n is 2.

[0069] In other embodiments, L1 is [ka] and L has the following structure: [ka] In preferred embodiments, n is 1, 2, 3, 4, 5, or 6. In even more preferred embodiments, n is 3 or 4.

[0070] In other embodiments, L1 is [ka] and L has the following structure: [ka] In preferred embodiments, n is 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. In even more preferred embodiments, n is 2, 3, 4, 5, 7, 7, 9, or 10.

[0071] In other embodiments, L1 is [ka] and L has the following structure: [ka] In preferred embodiments, m is 1, 2, 3, 4, 5, or 6, and n is 2, 4, or 6. In even more preferred embodiments, m is 1, 3, or 5, and n is 2.

[0072] In other embodiments, L1 is [ka] and L has the following structure: [ka] In preferred embodiments, n is 1, 2, 3, 4, 5, 6, 7, 8, or 9. In even more preferred embodiments, n is 1, 3, 5, 7, or 9.

[0073] In other embodiments, L1 is [ka] and L has the following structure: [ka] In preferred embodiments, m is 1, 2, 3, 4, 5, 6, 7, or 8. In even more preferred embodiments, m is 2, 4, or 6.

[0074] In other embodiments, L1 is [ka] and L is one of the following structures: [ka] In preferred embodiments, n is 1, 2, 3, 4, 5, 6, 7, or 8. In even more preferred embodiments, n is 2, 3, 4, or 5.

[0075] In additional embodiments, L1 is [ka] and L is one of the following structures: [ka] wherein n is 1, 2, or 3. In a preferred embodiment, n is 1.

[0076] In additional embodiments, L1 is [ka] and L is one of the following structures: [ka] wherein n is 1, 2, 3, 4, 5, 6, 7, 8, or 9. In a preferred embodiment, n is 1, 2, or 3. In a more preferred embodiment, n is 1.

[0077] In additional embodiments, L1 is [ka] and L is one of the following structures: [ka] wherein n is 1, 2, 3, 4, 5, 6, 7, 8, or 9. In preferred embodiments, n is 1, 2, or 3. In more preferred embodiments, n is 1.

[0078] In additional embodiments, L1 is [ka] and L has the following structure: [ka] wherein n is 1, 2, or 3. In a more preferred embodiment, n is 1.

[0079] In other embodiments, L1 is [ka] and L has the following structure: [ka] In preferred embodiments, n is 1, 2, or 3. In even more preferred embodiments, n is 1.

[0080] In further embodiments, L1 is a ring and -L2-L3-L4-L5- comprises at least one ring. The additional rings typically impart more rigidity to the linker moiety. In certain embodiments, L1 is [ka] and -L2-L3-L4-L5- is one of the following structures: [ka] [ka] It has.

[0081] In a more particular embodiment, L1 is [ka] and the linker (L) has one of the following structures: [ka] It has.

[0082] In a more particular embodiment, L1 is [ka] and the linker (L) has one of the following structures: [ka] (In the formula, R c is H or C 1~3 alkyl).

[0083] In a more particular embodiment, L1 is [ka] and the linker (L) has one of the following structures: [ka] It has.

[0084] In a more particular embodiment, L1 is [ka] and the linker (L) has one of the following structures: [ka] It has.

[0085] In a more particular embodiment, L1 is [ka] and the linker (L) has one of the following structures: [ka] It has.

[0086] In a more particular embodiment, L1 is [ka] and the linker (L) has one of the following structures: [ka] It has.

[0087] In a more particular embodiment, L1 is [ka] and the linker (L) has the following structure: [ka] It has.

[0088] In other embodiments, L1 is not a ring.

[0089] In other embodiments, the linker (L) or a portion of the linker moiety (-L-L s -) is one of the following structures: [ka] [ka] [ka] [ka] It has. Construction of compounds of formula (I)

[0090] The synthesis or construction of compounds of formula (I) can be carried out in multiple steps, typically involving the separate preparation of the IRAK4 binding and LHM moiety building blocks, followed by linking the individual building blocks by forming covalent bonds. Generally speaking, one or both of the building blocks may be linked to one or more linker precursors (L x The linker precursor may be prepared with one or more linker segments (L s ), which has a reactive end group for further coupling. The two building blocks are finally coupled to form (L s segment), compounds of formula (I) can be obtained.

[0091] The following schemes demonstrate general procedures for preparing building blocks: Examples 1-192 are specific examples of formula (I) that have been synthesized and characterized by their individual physicochemical properties. A. General scheme for preparing building blocks of IRAK4 binding moieties [ka]

[0092] Compounds of formula 1.5 can be accessed according to the methods outlined in Scheme 1. 1-Aminopyrrole 1.1 can be condensed with a suitable coupling partner using a suitable catalyst (e.g., HCl) and a suitable solvent (e.g., EtOH) to generate substituted pyrrolo[1,2-b]pyridazine 1.2. Halogenation at the indicated position using known halogenating reagents (e.g., NBS) can form intermediate 1.3, which can be further substituted by either CH activation or electrophilic aromatic substitution with a suitable reagent (e.g., selectfluor) to generate intermediate 1.4. Transition metal coupling using a suitable reagent (e.g., n-BuLi) or a palladium catalyst and metal source (e.g., B2Pin2, Me6Sn2, etc.) can then be used to achieve halogen-metal exchange of -X to -M to give intermediate 1.5. [ka]

[0093] Compounds of formula 2.3 can be accessed according to the method outlined in Scheme 2. Acid 2.1 can be converted to the corresponding acylhydrazine using a coupling reagent (such as HATU) in the presence of a base (such as DIPEA). Cyclization of compound 2.2 can be achieved by heating in the presence of a thiolation reagent (such as Lawesson's reagent) to give compound 2.3. [ka]

[0094] Compounds of formula 3.6 can be accessed following the methods outlined in Scheme 3. Dihalopyridine 3.1 can be converted to compound 3.2 by displacement of one of the halogen groups (e.g., nucleophilic aromatic substitution). Further functionalization of compound 3.2 using a metal-containing heterocyclic species (e.g., compound 1.5) with a suitable catalyst, such as a palladium catalyst, can provide compound 3.3. Halogenation at the indicated position using known halogenating reagents (e.g., NBS) can form intermediate 3.4, which can be further displaced by a cross-coupling reaction using a suitable catalyst, such as a palladium catalyst, to provide compound 3.5. [ka]

[0095] Compounds of formula 4.2 can be constructed according to Scheme A4. Displacement of the halogen group of halothiadiazole 4.1 with a nucleophile (e.g., an amine, etc.) (e.g., nucleophilic aromatic substitution) can provide compound 2.3. Halogenation at the indicated position using known halogenating reagents (e.g., NBS, etc.) can form intermediate 4.2. [ka]

[0096] Compounds of formula 3.5 can also be constructed according to Scheme A5. Halogen-metal exchange of -X to -M can then be achieved using a suitable reagent (e.g., n-BuLi, etc.) or transition metal coupling using a palladium catalyst and a metal source (e.g., B2Pin2, Me6Sn2, etc.) to afford intermediate 5.1. Functionalization of compound 5.1 can be accomplished using a cross-coupling reaction with compound 4.2 using a suitable catalyst, such as a palladium catalyst, to afford compound 3.5.

[0097] Under scheme A5, L xmay be a ring bearing a reactive moiety, which can then be linked to another linker segment. For example, a BOC-protected L x teeth, [ka] Compound 4.2 can be [ka] The resulting compound 3.5 is an IRAK4 binding moiety building block with an L1 precursor, a piperazine ring, which can be further linked to another linker segment via the reactive secondary amine of the piperazine. [ka]

[0098] An alternative method to access compound 3.5 is shown in Scheme A6. The corresponding acylhydrazine can be prepared starting from nicotinic acid 6.1 using a coupling reagent (e.g., HATU) in the presence of a base (e.g., DIPEA). Cyclization of compound 6.3 can be achieved by heating in the presence of a thiolation reagent (e.g., Lawesson's reagent) to give compound 6.4. Further functionalization of compound 6.4 with a metal-containing heterocyclic species (e.g., compound 1.5) using a suitable catalyst, such as a palladium catalyst, can give compound 3.5.

[0099] Under scheme A6, L x may be a ring bearing a reactive moiety, which can then be linked to another linker segment. For example, L x teeth, [ka] (optionally in BOC-protected form during synthesis) and the resulting compound 3.5 is a building block for another IRAK4 binding moiety bearing the L1 precursor, i.e., a bicyclo[2.2.2]octane ring, which can be further linked to another linker segment via a reactive primary amine.

[0100] Specific examples of preparing building blocks of IRAK4 binding moieties are described in further detail below.

[0101] BB1: 7-(5-(5-(4-aminobicyclo[2.2.2]octan-1-yl)-1,3,4-thiadiazol-2-yl)-4-((tetrahydro-2H-pyran-4-yl)amino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile hydrochloride. [ka]

[0102] Step 1: Methyl 6-chloro-4-((tetrahydro-2H-pyran-4-yl)amino)nicotinate. To a solution of methyl 4,6-dichloropyridine-3-carboxylate (4.00 g, 19.4 mmol) and tetrahydropyran-4-amine hydrochloride (4.01 g, 29.1 mmol) in THF (20.0 mL) was added DIPEA (10.1 mL, 58.2 mmol). The solution was stirred at 120 °C for 12 h and concentrated. The crude material was purified by SiO2 chromatography (eluent: 20-100% EtOAc / hexanes) to give methyl 6-chloro-4-((tetrahydro-2H-pyran-4-yl)amino)nicotinate. ES / MS: 271.238 (M+H + ).

[0103] Step 2: 6-chloro-4-((tetrahydro-2H-pyran-4-yl)amino)nicotinohydrazide. A solution of methyl 6-chloro-4-((tetrahydro-2H-pyran-4-yl)amino)nicotinate (3.03 g, 11.2 mmol) and hydrazine hydrate (4.55 g, 90.9 mmol) in ethanol (18.0 mL) was stirred at 80° C. for 3 hours and concentrated. This crude material was carried forward without further purification to give 6-chloro-4-((tetrahydro-2H-pyran-4-yl)amino)nicotinohydrazide. ES / MS: 271.201 (M+H + ).

[0104] Step 3: tert-Butyl (4-(2-(6-chloro-4-((tetrahydro-2H-pyran-4-yl)amino)nicotinoyl)hydrazine-1-carbonyl)bicyclo[2.2.2]octan-1-yl)carbamate. To a solution of 6-chloro-4-((tetrahydro-2H-pyran-4-yl)amino)nicotinohydrazide (2.70 g, 9.97 mmol), 4-(tert-butoxycarbonylamino)bicycle[2.2.2]octane-1-carboxylic acid (2.82 g, 10.5 mmol), and HATU (4.55 g, 12.0 mmol) in DMF (49.9 mL) was added DIPEA (5.70 mL, 31.9 mmol). The solution was stirred at room temperature for 30 minutes and concentrated to dryness. The crude material was purified by SiO chromatography (eluent: 5-15% MeOH / CHCl) to give tert-butyl (4-(2-(6-chloro-4-((tetrahydro-2H-pyran-4-yl)amino)nicotinoyl)hydrazine-1-carbonyl)bicyclo[2.2.2]octan-1-yl)carbamate. ES / MS: 522.894 (M+H). + ).

[0105] Step 4: tert-Butyl (4-(5-(6-chloro-4-((tetrahydro-2H-pyran-4-yl)amino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)bicyclo[2.2.2]octan-1-yl)carbamate. A solution of tert-butyl (4-(2-(6-chloro-4-((tetrahydro-2H-pyran-4-yl)amino)nicotinoyl)hydrazine-1-carbonyl)bicyclo[2.2.2]octan-1-yl)carbamate (5.00 g, 9.58 mmol) in 2-MeTHF (47.9 mL) was heated to 65° C. (external temperature). Lawesson's reagent (4.26 g, 10.5 mmol) was then added, and the reaction was stirred at 65° C. for 12 hours. The solution was concentrated to dryness and purified by SiO2 chromatography (eluent: 50-100% EtOAc / Hex). The combined product fractions were stirred over 10% palladium on carbon (5 g) for 1 h. The slurry was filtered through Celite, washing with CHCl2, and the filtrate was concentrated to dryness. The residue was purified by SiO2 chromatography (eluent: 1-5% MeOH / DCM) to give tert-butyl (4-(5-(6-chloro-4-((tetrahydro-2H-pyran-4-yl)amino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)bicyclo[2.2.2]octan-1-yl)carbamate. ES / MS: 520.288 (M+H + ).

[0106] Step 5: tert-Butyl (4-(5-(6-(3-cyanopyrrolo[1,2-b]pyridazin-7-yl)-4-((tetrahydro-2H-pyran-4-yl)amino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)bicyclo[2.2.2]octan-1-yl)carbamate. To a solution of tert-butyl (4-(5-(6-chloro-4-((tetrahydro-2H-pyran-4-yl)amino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)bicyclo[2.2.2]octan-1-yl)carbamate (65.0 mg, 0.103 mmol), 7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile (41.1 mg, 0.154 mmol), and [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (15.2 mg, 0.0205 mmol) in DME (2 mL) was added sodium carbonate (2.00 M, 0.205 mL, 0.410 mmol). The solution was degassed with argon for 2 minutes and heated to 120 °C (microwave) for 30 minutes. The resulting solution was diluted with THF, filtered, and concentrated to dryness. The crude solution was purified by preparative HPLC (Gemini C18, eluent: 10-65% acetonitrile / HO / 0.1% TFA) and lyophilized to give tert-butyl (4-(5-(6-(3-cyanopyrrolo[1,2-b]pyridazin-7-yl)-4-((tetrahydro-2H-pyran-4-yl)amino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)bicyclo[2.2.2]octan-1-yl)carbamate. ES / MS: 627.547 (M+H + ).

[0107] Step 6: 7-(5-(5-(4-aminobicyclo[2.2.2]octan-1-yl)-1,3,4-thiadiazol-2-yl)-4-((tetrahydro-2H-pyran-4-yl)amino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile bishydrochloride. To a solution of tert-butyl (4-(5-(6-(3-cyanopyrrolo[1,2-b]pyridazin-7-yl)-4-((tetrahydro-2H-pyran-4-yl)amino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)bicyclo[2.2.2]octan-1-yl)carbamate (28 mg, 0.0378 mmol) in 1,2-dichloroethane (0.189 mL) was added 4 M HCl in dioxane (4.00 M, 0.09 mL, 0.0378 mmol). The solution was stirred at room temperature for 1 hour and concentrated to dryness to give 7-(5-(5-(4-aminobicyclo[2.2.2]octan-1-yl)-1,3,4-thiadiazol-2-yl)-4-((tetrahydro-2H-pyran-4-yl)amino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile bishydrochloride. ES / MS: 527.366 (M+H + ). BB2: 7-(5-(5-((trans)-4-aminocyclohexyl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile hydrochloride [ka]

[0108] Step 1: tert-Butyl ((trans)-4-(2-(6-chloro-4-(isopropylamino)nicotinoyl)hydrazine-1-carbonyl)cyclohexyl)carbamate. To a solution of 6-chloro-4-(isopropylamino)pyridine-3-carbohydrazide (500 mg, 2.19 mmol), 4-(tert-butoxycarbonylamino)cyclohexanecarboxylic acid (612 mg, 2.52 mmol), and HATU (915 mg, 2.41 mmol) in DMF (9 mL) was added DIPEA (0.750 mL, 4.31 mmol). The solution was stirred at room temperature for 2 hours and diluted with EtOAc. The solution was then washed with a 1:1 mix of HO:saturated aqueous NH4Cl, saturated aqueous NH4Cl, and brine. The organic layer was dried over MgSO4 and concentrated to dryness. The crude material was purified by silica chromatography (eluent: 2-5% MeOH / CH2Cl2) to give tert-butyl ((trans)-4-(2-(6-chloro-4-(isopropylamino)nicotinoyl)hydrazine-1-carbonyl)cyclohexyl)carbamate. ES / MS: 454.944 (M+H). + ).

[0109] Step 2: tert-Butyl ((trans)-4-(5-(6-chloro-4-(isopropylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)cyclohexyl)carbamate. A solution of tert-butyl ((trans)-4-(2-(6-chloro-4-(isopropylamino)nicotinoyl)hydrazine-1-carbonyl)cyclohexyl)carbamate (739 mg, 1.63 mmol) in THF (15 mL) was heated to 65 °C (external temperature). Lawesson's reagent (978 mg, 2.42 mmol) was then added, and the reaction was stirred at 65 °C for 1 h. The solution was concentrated to dryness and purified by SiO chromatography (eluent: 5–35% EtOAc (5% MeOH) / Hex). The combined product fractions were stirred over 10% palladium on carbon (1 g) for 1 h. The slurry was filtered through Celite, washed with CHCl, and the filtrate was concentrated to dryness. The residue was purified by SiO chromatography (eluent: 10-40% acetone / Hex) to give tert-butyl ((trans)-4-(5-(6-chloro-4-(isopropylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)cyclohexyl)carbamate. ES / MS: 452.725 (M+H). + ).

[0110] Step 3: tert-Butyl ((trans)-4-(5-(6-(3-cyanopyrrolo[1,2-b]pyridazin-7-yl)-4-(isopropylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)cyclohexyl)carbamate. To a solution of tert-butyl ((trans)-4-(5-(6-chloro-4-(isopropylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)cyclohexyl)carbamate (200 mg, 0.442 mmol), 7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile (190 mg, 0.706 mmol), and XPhos Pd G3 (28.0 mg, 0.0331 mmol) in a mixture of DMF (2.25 mL) and DME (2 mL) was added potassium phosphate tribasic (2.00 M, 0.450 mL, 0.900 mmol). The solution was degassed with argon for 2 min and heated to 120 °C (microwave) for 20 min. Additional 7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile (92.0 mg, 0.342 mmol) and XPhos Pd G3 (11.0 mg, 0.0130 mmol) were added, and the solution was heated to 120 °C (microwave) for 20 min. The resulting solution was diluted with MeOH and concentrated to dryness. The residue was purified by silica chromatography (eluent: 2–5% MeOH / CHCl) to give tert-butyl ((trans)-4-(5-(6-(3-cyanopyrrolo[1,2-b]pyridazin-7-yl)-4-(isopropylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)cyclohexyl)carbamate. ES / MS: 559.658(M+H + ).

[0111] Step 4: 7-(5-(5-((trans)-4-aminocyclohexyl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile bishydrochloride. To a solution of tert-butyl ((trans)-4-(5-(6-(3-cyanopyrrolo[1,2-b]pyridazin-7-yl)-4-(isopropylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)cyclohexyl)carbamate (228 mg, 0.408 mmol) in a mixture of CHCl (4 mL) and MeOH (4 mL) was added 4 M HCl in dioxane (4.00 M, 2.00 mL, 8.00 mmol). The solution was stirred at 45° C. for 18 hours and concentrated to dryness to give 7-(5-(5-((trans)-4-aminocyclohexyl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile bishydrochloride. ES / MS: 459.629 (M+H + ). BB3: 7-(5-(5-((1r,4r)-4-aminocyclohexyl)-1,3,4-thiadiazol-2-yl)-4-(methylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile [ka]

[0112] Step 1: Methyl 6-chloro-4-(methylamino)nicotinate. To a solution of methyl 4,6-dichloronicotinate (95.0 g, 461 mmol, 1.00 equiv.) in acetonitrile (1000 mL) at 0 °C, methanamine (288 g, 2.32 mol, 25% purity, 5.03 equiv.) was slowly added. The mixture was stirred at 0 °C for 0.5 h and then at 25 °C for 2 h. TLC (petroleum ether:ethyl acetate = 5:1) showed that 4,6-dichloronicotinate (Rf = 0.40) had been consumed and a new spot (Rf = 0.30) had formed. The reaction mixture was concentrated under reduced pressure and extracted with ethyl acetate (3 × 500 mL). The combined organic layers were washed with brine (2 × 500 mL), dried over Na2SO4, filtered, and the filtrate was concentrated under reduced pressure to give the crude product. The crude product was purified by column chromatography (SiO, petroleum ether:ethyl acetate = 20:1 to 10:1, Rf = 30). Methyl 6-chloro-4-(methylamino)nicotinate (39.0 g, 184 mmol, 40.0% yield, 95.0% purity) was obtained as a white solid. LCMS: C8H9ClN2O2 requires: 200.04, found m / z = 201.1 (M+H). + . 1 H NMR: (400 MHz CDCl) δ 8.65 (s, 1H), 8.08 (s, 1H), 6.54 (s, 1H), 3.88 (s, 3H), 2.92 (d, J = 5.2 Hz, 3H). BB3 was synthesized using the same reaction sequence as BB2, starting from 6-chloro-4-(methylamino)pyridine-3-carbohydrazide. LCMS: C 22 H 22 N8S Theoretical value: 430.17, Measured value: m / z = 431.39 [M+H] + . BB4: 7-(4-(isopropylamino)-5-(5-(piperazin-1-yl)-1,3,4-thiadiazol-2-yl)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile [ka]

[0113] Step 1: tert-Butyl 4-(5-bromo-1,3,4-thiadiazol-2-yl)piperazine-1-carboxylate. tert-Butyl piperazine-1-carboxylate (1.6 g, 8.6 mmol, 1.05 equiv.) and dibromo-1,3,4-thiadiazole (2.0 g, 8.2 mmol) were combined in dioxane (0.15 M), followed by the addition of N,N-diisopropylethylamine (2.5 mL, 14.4 mmol). The vial was then capped and heated to 110° C. for 90 minutes. The reaction was then cooled to room temperature, concentrated onto silica gel, and purified by column chromatography (0-5% methanol in DCM) to give tert-butyl 4-(5-bromo-1,3,4-thiadiazol-2-yl)piperazine-1-carboxylate (2.0 g, 70%). LCMS: C 11 H 17 BrNOS Theoretical value: 348.0, Measured value: m / z = 351.1 [M+H] + .

[0114] Step 2: tert-Butyl 4-(5-(6-(3-cyanopyrrolo[1,2-b]pyridazin-7-yl)-4-(isopropylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)piperazine-1-carboxylate. In a microwave-safe vial, 6-{3-cyanopyrrolo[1,2-b]pyridazin-7-yl}-4-(isopropylamino)pyridin-3-ylboronic acid (1.5 g, 4.7 mmol), cesium carbonate (3.5 g, 10.7 mmol), Xantphos (0.54 g, 0.93 mmol), palladium acetate (105 mg, 0.47 mmol), and tert-butyl 4-(5-bromo-1,3,4-thiadiazol-2-yl)piperazine-1-carboxylate (1.6 g, 4.7 mmol) were combined in dioxane (0.15 M). Nitrogen was bubbled through the reaction mixture for 1 minute and then capped. The mixture was microwaved at 145°C for 35 minutes, then cooled to room temperature and filtered through Celite. The Celite pad was washed with ethyl acetate, and the combined organics were concentrated onto silica gel. Chromatography (0-10% methanol in DCM) afforded tert-butyl 4-(5-(6-(3-cyanopyrrolo[1,2-b]pyridazin-7-yl)-4-(isopropylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)piperazine-1-carboxylate, which was used directly in the next step.

[0115] Step 3: 7-[4-(isopropylamino)-5-[5-(piperazin-1-yl)-1,3,4-thiadiazol-2-yl]pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile. tert-Butyl 4-(5-(6-(3-cyanopyrrolo[1,2-b]pyridazin-7-yl)-4-(isopropylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)piperazine-1-carboxylate was stirred in a minimum amount of dioxane, followed by the addition of 4N dioxane (5 mL) and stirring for 5 hours. The reaction was then concentrated onto silica by rotary evaporation and chromatographed (0-20% methanol in DCM) to give 7-[4-(isopropylamino)-5-[5-(piperazin-1-yl)-1,3,4-thiadiazol-2-yl]pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile (0.5 g, 24% yield over two steps). LCMS: C 22 H 23 N9S Theoretical value: 445.6, Measured value: m / z = 446.4 [M+H] + . BB5: 7-[4-(isopropylamino)-5-{5-[4-(piperidine-4-carbonyl)piperazin-1-yl]-1,3,4-thiadiazol-2-yl}pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile [ka]

[0116] Step 1: 1-(5-Bromo-1,3,4-thiadiazol-2-yl)-piperazine. tert-Butyl 4-(5-bromo-1,3,4-thiadiazol-2-yl)piperazine-1-carboxylate (1 g, 2.9 mmol) was dissolved in DCM (0.15 M), followed by the addition of trifluoroacetic acid (0.05 M volume) and stirring at room temperature for 3 hours. The reaction was then concentrated, redissolved in ether, concentrated, and dried in vacuo (0.6 g, 84%). The crude 1-(5-bromo-1,3,4-thiadiazol-2-yl)-piperazine was used directly in the next reaction. LCMS: C6H9BrN4S Calculated: 248.0, Found: m / z = 249.1 [M+H] + .

[0117] Step 2: tert-Butyl 4-[4-(5-bromo-1,3,4-thiadiazol-2-yl)piperazine-1-carbonyl]piperidine-1-carboxylate. To a solution of 1-(tert-butoxycarbonyl)piperidine-4-carboxylic acid (276 mg, 1.2 mmol) and HATU (570 mg, 1.5 mmol) in DMF (5 mL) and triethylamine (0.6 mL, 4.2 mmol) was added 1-(5-bromo-1,3,4-thiadiazol-2-yl)piperazine (300 mg, 1.2 mmol). The reaction was stirred at room temperature for 18 hours. The reaction was then partitioned between ethyl acetate and water. The aqueous layer was re-extracted with ethyl acetate. The combined organics were washed with brine, then dried over magnesium sulfate and concentrated onto silica gel. Silica gel chromatography (0-10% methanol in DCM) gave tert-butyl 4-[4-(5-bromo-1,3,4-thiadiazol-2-yl)piperazine-1-carbonyl]piperidine-1-carboxylate (0.2 g, 36%). LCMS: C 17 H 26 BrN5O3S Theoretical value: 460.4, Measured value: m / z = 484.3 [M + Na] + .

[0118] Step 3: 7-[4-(Isopropylamino)-5-{5-[4-(piperidine-4-carbonyl)piperazin-1-yl]-1,3,4-thiadiazol-2-yl}pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile. 6-{3-cyanopyrrolo[1,2-b]pyridazin-7-yl}-4-(isopropylamino)pyridin-3-ylboronic acid (150 mg, 0.47 mmol), cesium carbonate (0.42 g, 1.3 mmol), Xantphos (0.11 g, 0.19 mmol), palladium acetate (21 mg, 0.09 mmol), and tert-butyl 4-[4-(5-bromo-1,3,4-thiadiazol-2-yl)piperazine-1-carbonyl]piperidine-1-carboxylate were combined in a microwave vial, followed by the addition of dioxane (0.1 M) and a nitrogen purging. The mixture was irradiated in a microwave reactor at 145 °C for 30 min, then cooled and filtered through Celite. The solution was concentrated onto silica gel and chromatographed (0-10% methanol in DCM). This material was then subjected to 4N HCl in dioxane (0.15 M) and stirred for 2 hours. The reaction was then concentrated to give 7-[4-(isopropylamino)-5-{5-[4-(piperidine-4-carbonyl)piperazin-1-yl]-1,3,4-thiadiazol-2-yl}pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile (0.1 g, 39% overall over two steps). LCMS: C 28 H 32 N 10 OS theoretical value: 556.7, measured value: m / z = 557.4 [M+H] + . BB6: 7-[4-(isopropylamino)-5-{5-[4-(piperidin-4-yl)piperazin-1-yl]-1,3,4-thiadiazol-2-yl}pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile [ka]

[0119] Step 1: tert-Butyl 4-[4-(5-bromo-1,3,4-thiadiazol-2-yl)piperazin-1-yl]piperidine-1-carboxylate. 1-(5-Bromo-1,3,4-thiadiazol-2-yl)piperazine (300 mg, 1.2 mmol) and tert-butyl 4-oxopiperidine-1-carboxylate were combined in DCE (0.2 M) and TEA (0.5 mL, 3.6 mmol). After stirring for 5 minutes, sodium triacetoxyborohydride (0.45 g, 2.1 mmol) was added in one portion. The reaction was stirred at room temperature for 3 hours, then filtered through Celite and concentrated onto silica gel. Chromatography (0-10% methanol in DCM) afforded the desired tert-butyl 4-[4-(5-bromo-1,3,4-thiadiazol-2-yl)piperazin-1-yl]piperidine-1-carboxylate (0.2 g, 39%). LCMS: C 16 H 26 N5O2SBr Theoretical value: 432.4, Measured value: m / z = 456.3 [M + Na] + .

[0120] Step 2: tert-Butyl 4-{4-[5-(6-{3-cyanopyrrolo[1,2-b]pyridazin-7-yl}-4-(isopropylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl]piperazin-1-yl}piperidine-1-carboxylate. 6-{3-cyanopyrrolo[1,2-b]pyridazin-7-yl}-4-(isopropylamino)pyridin-3-ylboronic acid (150 mg, 0.47 mmol), Xantphos (110 mg, 0.19 mmol), cesium carbonate (0.42 g, 1.28 mmol), palladium acetate (21 mg, 0.09 mmol), and tert-butyl 4-[4-(5-bromo-1,3,4-thiadiazol-2-yl)piperazin-1-yl]piperidine-1-carboxylate (200 mg, 0.47 mmol) were combined in a microwave vial, followed by the addition of dioxane (0.15 M). The reaction mixture was purged with nitrogen for 30 seconds, then capped and microwaved at 145°C for 30 minutes. The reaction was then cooled, filtered through Celite, and concentrated onto silica gel. Chromatography (0-10% methanol in DCM) afforded tert-butyl 4-{4-[5-(6-{3-cyanopyrrolo[1,2-b]pyridazin-7-yl}-4-(isopropylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl]piperazin-1-yl}piperidine-1-carboxylate (100 mg, 34%). LCMS: C 32 H 40 N 10 O2S theoretical value: 626.8, measured value: m / z = 629.7 [M+H] + .

[0121] Step 3: 7-[4-(isopropylamino)-5-{5-[4-(piperidin-4-yl)piperazin-1-yl]-1,3,4-thiadiazol-2-yl}pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile. tert-Butyl 4-{4-[5-(6-{3-cyanopyrrolo[1,2-b]pyridazin-7-yl}-4-(isopropylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl]piperazin-1-yl}piperidine-1-carboxylate (100 mg) was dissolved in dioxane (1 mL), and then 4N HCl in dioxane (1 mL) was added. The reaction was stirred for 2 hours and then concentrated to give 7-[4-(isopropylamino)-5-{5-[4-(piperidin-4-yl)piperazin-1-yl]-1,3,4-thiadiazol-2-yl}pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile hydrochloride salt (0.08 g, 95%), which was used without further purification. LCMS: C 27 H 32 N 10 S Theoretical value: 528.7, Measured value: m / z = 529.7 [M+H] + . BB7: 7-(5-(5-(4-aminopiperidin-1-yl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile hydrochloride [ka]

[0122] Step 1: tert-Butyl N-[1-(5-bromo-1,3,4-thiadiazol-2-yl)piperidin-4-yl]carbamate. Dibromo-1,3,4-thiadiazole (1.0 g, 4.1 mmol), tert-butyl N-(piperidin-4-yl)carbamate (840 mg, 4.2 mmol) were dissolved in dioxane (0.15 M), and then N,N-diisopropylethylamine (1.25 mL, 7.2 mmol) was added. The reaction was heated to 110 °C in a sealed vial and stirred for 90 minutes. The reaction was then cooled and concentrated onto silica gel. Column chromatography (0-5% methanol in DCM) afforded tert-butyl N-[1-(5-bromo-1,3,4-thiadiazol-2-yl)piperidin-4-yl]carbamate (1.0 g, 67%). LCMS:C 12 H 19 BrNOS Theoretical value: 363.3, Measured value: m / z = 365.3 [M+H] + .

[0123] Step 2: tert-Butyl N-{1-[5-(6-{3-cyanopyrrolo[1,2-b]pyridazin-7-yl}-4-(isopropylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl]piperidin-4-yl}carbamate. 6-{3-cyanopyrrolo[1,2-b]pyridazin-7-yl}-4-(isopropylamino)pyridin-3-ylboronic acid (90 mg, 0.28 mmol), cesium carbonate (0.25 g, 0.77 mmol), Xantphos (0.06 g, 0.11 mmol), palladium acetate (13 mg, 0.06 mmol), and tert-butyl N-[1-(5-bromo-1,3,4-thiadiazol-2-yl)piperidin-4-yl]carbamate (102 mg, 0.28 mmol) were combined in a microwave vial, followed by the addition of dioxane (0.15 M) and a nitrogen purging. The reaction was stirred at room temperature for 3 minutes and then microwaved at 145° C. for 30 minutes. The reaction was cooled, filtered through Celite, and concentrated onto silica gel. Column chromatography (0–5% methanol in DCM) afforded tert-butyl N-{1-[5-(6-{3-cyanopyrrolo[1,2-b]pyridazin-7-yl}-4-(isopropylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl]piperidin-4-yl}carbamate (0.1 g, 64%).

[0124] Step 3: 7-(5-(5-(4-aminopiperidin-1-yl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile hydrochloride. To a solution of tert-butyl N-{1-[5-(6-{3-cyanopyrrolo[1,2-b]pyridazin-7-yl}-4-(isopropylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl]piperidin-4-yl}carbamate was added excess 4N HCl to give the title compound. LCMS: C 23 H 25 N9S Theoretical value: 459.2, Measured value: m / z = 460.5 [M+H] + . BB8: 7-(5-(5-(3,9-diazaspiro[5.5]undecan-3-yl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile [ka]

[0125] BB8 was synthesized following the same route as BB4, except that tert-butyl 3,9-diazaspiro[5.5]undecane-3-carboxylate was used as the amine in step 1. LCMS: C 27 H 31 N9S Theoretical value: 513.2, Measured value: m / z = 514.6 [M+H] + . BB9: 7-(4-(methylamino)-5-(5-(4-(piperidine-4-carbonyl)piperazin-1-yl)-1,3,4-thiadiazol-2-yl)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile [ka]

[0126] BB9 was synthesized following the same route as BB5, except that (6-(3-cyanopyrrolo[1,2-b]pyridazin-7-yl)-4-(methylamino)pyridin-2-yl)boronic acid was used in step 3. LCMS: C 26 H 28 N 10 OS theoretical value: 528.2, measured value: m / z = 529.4 [M+H] + . BB10: 7-[4-(methylamino)-5-[5-(piperazin-1-yl)-1,3,4-thiadiazol-2-yl]pyridin-2-yl]pyrolo[1,2-b]pyridazine-3-carbonitrile [ka]

[0127] Step 1: 2-Bromo-N-methylpyridin-4-amine. To a mixture of 2-bromo-4-fluoro-pyridine (25.0 g, 0.142 mol, 1.0 eq.) was added methylamine (9.8 M) in methanol (142 ml, 1.42 mol, 10 eq.), and the resulting mixture was heated at 80° C. overnight. Upon completion, the reaction mixture was cooled, all volatiles were evaporated in vacuo, dissolved in EtOAc, and washed with water. The organic layer was dried over sodium sulfate, filtered, and concentrated to give the desired product. (25 g, 89% yield): ESI(+)[M+H] + =188.94; 1 H NMR (300 MHz, DMSO-d6), δ: 7.77 (d, J = 5.8 Hz, 1H), 6.98 - 6.78 (m, 1H), 6.59 (m, 1H), 6.48 (m, 1H), 2.69 (d, J = 4.9 Hz, 3H).

[0128] Step 2: 7-[4-(methylamino)pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile. To a solution of 2-bromo-N-methylpyridin-4-amine (6.0 g, 32.08 mmol, 1.0 equiv), 7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile (12.09 g, 44.91 mmol, 1.4 equiv), and Xphos G3 (2.17 g, 2.57 mmol, 0.08 equiv) in anhydrous dimethoxyethane (80 mL, 0.4 M) was added 2 M aqueous KPO (32.1 mL, 64.16 mmol, 2.0 equiv). The solution was degassed with argon for 15 minutes and then heated at 120°C overnight with vigorous stirring. The reaction mixture was filtered through Celite and the solvent evaporated to dryness under reduced pressure. The crude residue was purified by chromatography using methanol (0-10%) in dichloromethane to give the desired product as a yellow solid (6.1g, 76% yield); 1H NMR (300 MHz, DMSO-d6), δ: 8.79 (d, J = 2.2 Hz, 1H,), 8.64 (d, J = 2.2 Hz, 1H,), 8.19 (d, J = 5.6, 1H,), 7.87 (d, J = 2.3, 1H,), 7.76 (d, ESI(+)[M+H] + = 250.36.

[0129] Step 3: 7-[5-Bromo-4-(methylamino)pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile. 7-[4-(methylamino)-2-pyridyl]pyrrolo[1,2-b]pyridazine-3-carbonitrile (5.3 g, 20.05 mmol, 1.0 equiv.) was dissolved in acetonitrile (65 ml, 0.3 M) and dichloromethane (20 ml, 0.7 M) at room temperature, and N-bromosuccinimide (3.57 g, 20.05 mmol, 1.0 equiv.) was added in one portion. The reaction was stirred at ambient conditions for 30 minutes. Upon completion, the mixture was evaporated under reduced pressure, and the resulting residue was purified by chromatography using 0-5% ethyl acetate in dichloromethane to give the product as a yellow solid (5.95 g, 88% yield). 1 H NMR (300 MHz, DMSO-d6), δ: 8.80 (d, J = 2.2 Hz, 1H), 8.67 (d, J = 2.2 Hz, 1H), 8.36 (s, 1H), 7.94 (s, 1H), 7.76 (d, J = 4.8 Hz, 1H), 7.08 (d, J = 4.8 Hz, 1H), 6.45 (q, J = 4.3 Hz, 1H), 2.90 (d, J = 4.7 Hz, 3H); ESI(+)[M+H] + = 330.16.

[0130] Step 4: tert-Butyl 4-(1,3,4-thiadiazol-2-yl)piperazine-1-carboxylate. To a solution of 2-bromo-1,3,4-thiadiazole (7.292 g, 42.424 mmol, 1.0 equiv.) and tert-butyl piperazine-1-carboxylate hydrochloride (19.75 g, 106.05 mmol, 2.5 equiv.) in n-butanol (83.18 mL, 0.51 M) was added N,N-diisopropylethylamine (29.57 mL, 169.68 mmol, 4.0 equiv.). The reaction mixture was heated at 120 °C for 1 hour. Upon completion, the mixture was cooled and concentrated in vacuo to afford the crude product. Chromatographic purification (0-70% ethyl acetate in hexanes) afforded the desired compound as a pink crystalline solid (9.93 g, 86% yield). 1 H NMR (300 MHz, DMSO-d6), δ: 8.84 (s, 1H), 3.46 (s, 8H), 1.42 (s, 9H); ESI(+)[M+H] + = 272.16.

[0131] Step 5: tert-butyl 4-[5-(6-{3-cyanopyrrolo[1,2-b]pyridazin-7-yl}-4-(methylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl]piperazine-1-carboxylate. 7-[5-bromo-4-(methylamino)pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile (0.5 g, 1.524 mmol, 1.0 equiv.), palladium(II) acetate (0.051 g, 0.227 mmol, 0.15 equiv.), 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene (0.26 g, 0.45 mmol, 0.3 equiv.), cesium carbonate. (0.1 g, 3.05 mmol, 2.0 equiv.) and cuprous iodide (0.087 g, 0.457 mmol, 0.3 equiv.) were dissolved in an oven-dried screw-cap vial, to which tert-butyl 4-(1,3,4-thiadiazol-2-yl)piperazine-1-carboxylate (0.434 g, 1.53 mmol, 1 equiv.) and dioxane (25.39 ml, 0.06 M) were added. The reaction tube was evacuated and backfilled with argon for 20 minutes, sealed, and then heated at 105 °C overnight. After completion of the reaction (confirmed by UPLC), all volatiles were evaporated in vacuo, and the resulting residue was purified by chromatography (0-31% ethyl acetate in dichloromethane) to afford the desired product as a yellow crystalline solid (0.57 g, 61% yield). 1 H NMR (300 MHz, DMSO-d6), δ: 8.83 (s, 1H), 8.73 (s, 1H), 8.48 (m, 2H), 8.14 (s, 1H), 7.86 (s, 1H), 7.12 (d, J = 4.8 Hz, 1H), 3.54 (s, 8H), 3.06 (d, J = 4.9 Hz, 3H), 1.44 (s, 9H); ESI(+)[M+H] + = 518.64.

[0132] Step 6: 7-[4-(methylamino)-5-[5-(piperazin-1-yl)-1,3,4-thiadiazol-2-yl]pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile. A solution of tert-butyl 4-[5-(6-{3-cyanopyrrolo[1,2-b]pyridazin-7-yl}-4-(methylamino)-pyridin-3-yl)-1,3,4-thiadiazol-2-yl]piperazine-1-carboxylate (0.25 g, 0.48 mmol, 1 equiv.) in 1,1,1,3,3,3-hexafluoro-2-propanol (0.769 ml, 7.25 mmol, 15 equiv.) was heated at 140° C. for 3 hours using a MW of 1. All volatiles were evaporated under reduced pressure and the remaining residue was purified by chromatography (0-7% methanol in dichloromethane) to give the target product as a yellow solid (0.15 g, 73% yield): LCMS: ESI(+) [M+H] + =418.06; 1 H NMR (300 MHz, DMSO-d6), δ: 8.83 (d, J = 2.2 Hz, 1H), 8.72 (s, 1H), 8.54 - 8.42 (m, 2H), 8.13 (s, 1H), 7.85 (d, J = 4.8 Hz, 1H), 7.11 (d, J = 4.8 Hz, 1H), 3.46 (s, 4H), 3.06 (d, J = 4.9 Hz, 3H), 2.84 (s, 4H), 2.61 (br m, 1H). BB11: 7-(5-(5-(4-aminopiperidin-1-yl)-1,3,4-thiadiazol-2-yl)-4-(methylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile [ka]

[0133] BB11 was synthesized following the same route as BB7, except that (6-(3-cyanopyrrolo[1,2-b]pyridazin-7-yl)-4-(methylamino)pyridin-2-yl)boronic acid was used in step 2. LCMS: C 21 H 21N9S Theoretical value: 431.2, Measured value: m / z = 432.4 [M+H] + . BB12: 7-(4-(methylamino)-5-(5-(4-(piperidin-4-yl)piperazin-1-yl)-1,3,4-thiadiazol-2-yl)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile [ka]

[0134] BB12 was synthesized following the same route as BB6, except that (6-(3-cyanopyrrolo[1,2-b]pyridazin-7-yl)-4-(methylamino)pyridin-2-yl)boronic acid was used in step 2. LCMS: C 25 H 28 N 10 S Theoretical value: 500.2, Measured value: m / z = 501.5 [M+H] + . BB13: 7-(5-(5-(4-aminobicyclo[2.2.2]octan-1-yl)-1,3,4-thiadiazol-2-yl)-4-(methylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile [ka]

[0135] BB13 was synthesized following the same route as BB3, except for using 4-((tert-butoxycarbonyl)amino)bicyclo[2.2.2]octane-1-carboxylic acid in step 1. LCMS: C 24 H 24 N8S theoretical value: 456.2, measured value: m / z = 457.1 [M+H] + . BB14: 7-(5-(5-((1s,4s)-4-aminocyclohexyl)-1,3,4-thiadiazol-2-yl)-4-(methylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile [ka]

[0136] BB14 was synthesized following the same route as BB3, except for using cis-4-(tert-butoxycarbonylamino)cyclohexanecarboxylic acid in step 1. LCMS: C 22 H 22 N8S Theoretical value: 430.2, Measured value: m / z = 431.3 [M+H] + . BB15: 7-(5-(5-(2,6-diazaspiro[3.5]nonan-6-yl)-1,3,4-thiadiazol-2-yl)-4-(methylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile [ka]

[0137] BB15 was synthesized following the same route as BB10, except that tert-butyl 2,6-diazaspiro[3.5]nonane-2-carboxylate was used as the amine in step 1. LCMS: C 23 H 23 N9S Theoretical value: 457.2, Measured value: m / z = 458.3 [M+H] + . BB16: 7-(4-(methylamino)-5-(5-(4-(piperazine-1-carbonyl)piperazin-1-yl)-1,3,4-thiadiazol-2-yl)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile [ka]

[0138] BB10 (55 mg, 0.22 mmol) was stirred with tert-butyl 4-(carboxy)piperazine-1-carboxylate (1 equivalent) in DIEA (2.2 equivalents) and DMF (0.2 M) at room temperature for 5 hours. The reaction was then partitioned between ethyl acetate and water. The organic layer was separated, dried over magnesium sulfate, and concentrated. The crude material was directly dissolved in DCM:TFA (4:1 ratio, 0.1 M) and stirred for 18 hours. The reaction was then concentrated to dryness and triturated with diethyl ether to give the desired product (30 mg, 26% yield). LCMS: C 25 H 27 N 11 OS theoretical value: 529.6, measured value: m / z = 530.5 [M+H] + . BB17: 7-(4-(methylamino)-5-(5-(4-(piperazine-1-carbonyl)piperidin-1-yl)-1,3,4-thiadiazol-2-yl)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile [ka]

[0139] Step 1: Ethyl 1-(5-(6-(3-cyanopyrrolo[1,2-b]pyridazin-7-yl)-4-(methylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)piperidine-4-carboxylate. 6-{3-cyanopyrrolo[1,2-b]pyridazin-7-yl}-4-(methylamino)pyridin-3-ylboronic acid (200 mg, 0.68 mmol) was combined with cesium carbonate (2.75 equiv.), Xantphos (0.4 equiv.), (acetyloxy)palladio acetate (0.2 equiv.), and ethyl 1-(5-bromo-1,3,4-thiadiazol-2-yl)piperidine-4-carboxylate (1 equiv., see Step 1 of BB4) in a microwave vial, followed by the addition of dioxane (8 mL). The reaction was then purged with N2 for 1 min in a microwave reactor, stirred for 3 min, and then microwaved at 145 °C for 30 min. The reaction was then filtered through Celite and concentrated onto silica gel. Chromatography (0-10% methanol in DCM) afforded the desired product.

[0140] Step 2: 1-(5-(6-(3-cyanopyrrolo[1,2-b]pyridazin-7-yl)-4-(methylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)piperidine-4-carboxylic acid. Hydrolysis of the ester was carried out using THF / ethanol (10:1) and 2 mL of 2 M LiOH (aq). The reaction was stirred for 3 h, then dried onto silica gel and chromatographed (C18 column, 0-100% acetonitrile in water) to give the desired acid (100 mg, 32% overall for two steps).

[0141] Step 3: 7-(4-(methylamino)-5-(5-(4-(piperazine-1-carbonyl)piperidin-1-yl)-1,3,4-thiadiazol-2-yl)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile. The above carboxylic acid (100 mg) was combined with HATU (1.25 eq), DIEA (5 eq) in DMF (0.1 M) and stirred for 10 minutes, after which tert-butyl piperazine-1-carboxylate (1.2 eq) was added. The reaction was stirred for 24 hours and then partitioned between ethyl acetate and water. The organic layer was separated and then redissolved in DCM / TFA (4:1, 0.1 M) and stirred overnight. After concentration, the crude material was obtained and used as is (50 mg, 44% yield): LCMS: C 26 H 28 N 10 OS theoretical value: 528.64, measured value: m / z = 529.6 [M+H] + . BB18: 7-[4-(methylamino)-5-{5-[(1r,4r)-4-(methylamino)cyclohexyl]-1,3,4-thiadiazol-2-yl}pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile [ka]

[0142] Step 1: Methyl (1r,4r)-4-{[(tert-butoxy)carbonyl](methyl)amino}cyclohexane-1-carboxylate. Methyl trans-4-(tert-butoxycarbonylamino)cyclohexanecarboxylate (3.0 g, 11.658 mmol, 1.0 equiv.) was dissolved in DMF (20 mL, 0.6 M) and cooled to 0° C. Next, NaH (0.536 g, 13.99 mmol, 1.2 equiv.) was added, and the reaction mixture was stirred at 0° C. for 30 minutes. Methyl iodide (1.09 mL, 17.49 mmol, 1.5 equiv.) was then added, the cooling bath was removed, and the reaction mixture was stirred at room temperature for 18 hours. The mixture was poured into saturated aqueous ammonium chloride and extracted with ethyl acetate. The crude material was purified with hexane:EtOAc to give 1.4 g (44% yield) of the desired product. 1 H NMR (300 MHz, DMSO-d6) δ 3.58 (s, 3H), 2.64 (s, 3H), 2.25 (tt, J = 11.7, 3.6 Hz, 1H), 1.94 (dt, J = 12.3, 2.6 Hz, 2H), 1.60 - 1.41 (m, 4H), 1.38 (d, J = 1.6 Hz, 12H).

[0143] Step 2: (1r,4r)-4-{[(tert-butoxy)carbonyl]amino}cyclohexane-1-carboxylic acid. Methyl (1r,4r)-4-{[(tert-butoxy)carbonyl](methyl)amino}cyclohexane-1-carboxylate (1.3 g, 4.79 mmol, 1.0 equiv.) was dissolved in THF (18 mL, 0.27 M). A solution of LiOH (4.8 mL, 4.79 mmol, 2.0 equiv.) was then added and stirred at room temperature for 5 hours. TLC indicated the remaining starting material, so an additional portion of LiOH (2.4 mL, 2.39 mmol, 1.0 equiv.) was added, and the reaction mixture was stirred overnight. TLC indicated complete conversion, so the mixture was quenched with a saturated solution of KHSO4 until pH < 5 and extracted with DCM to give 1.18 g (96% yield) of the desired product as the free acid. 1H NMR (300 MHz, DMSO-d6) δ 3.90- 3.52 (m, 1H) 2.65 (s, 3H), 2.13 (tt, J = 11.7, 3.6 Hz, 1H), 2.02 - 1.91 (m, 2H), 1.66 - 1.45 (m, 4H), 1.39 (d, J = 1.2 Hz, 11H).

[0144] Step 3: tert-Butyl N-methyl-N-[(1r,4r)-4-{N'-[6-chloro-4-(methylamino)pyridine-3-carbonyl]hydrazinecarbonyl}cyclohexyl]carbamate. To a solution of 6-chloro-4-(methylamino)pyridine-3-carbohydrazide (0.84 g, 0.7975 mmol, 1.0 equiv.) and (1r,4r)-4-{[(tert-butoxy)carbonyl]amino}cyclohexane-1-carboxylic acid (1.19 g, 4.61 mmol, 1.1 equiv.) in DMF (10 mL) was added DIPEA (2.2 mL, 12.56 mmol, 3.0 equiv.) and HATU (1.91 g, 5.024 mmol, 1.2 equiv.). The mixture was stirred at 25 °C for 1 hour. UPLC indicated the mass of the desired product. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with water, brine, dried over Na2SO4, and concentrated to give the crude product. The crude product was purified by chromatography eluting with DCM:MeOH (0-10%) to give 1.18 g (64% yield) of the desired product: ESI(+) [M+H] + =440.6; 1 H NMR (300 MHz, DMSO-d6) δ 10.30 (s, 1H), 9.78 (s, 1H),8.33 (s, 1H), 8.11 (s, 1H), 6.66 (s, 1H), 2.82 (d, 3H), 2.65 (s, 3H), 2.13 (tt, J = 11.7, 3.6 Hz, 1H), 2.02 - 1.91 (m, 2H), 1.66 - 1.45 (m, 4H), 1.39 (d, J = 1.2 Hz, 12H).

[0145] Step 4: tert-Butyl N-methyl-N-[(1r,4r)-4-{5-[6-chloro-4-(methylamino)pyridin-3-yl]-1,3,4-thiadiazol-2-yl}cyclohexyl]carbamate. To a suspension of tert-butyl N-methyl-N-[(1r,4r)-4-{N'-[6-chloro-4-(methylamino)pyridine-3-carbonyl]hydrazinecarbonyl}cyclohexyl]carbamate (1.18 g, 2.68 mmol, 1.0 equiv.) in dry toluene (50 mL, 0.05 M) was added Lawesson's reagent (1.20 g, 2.95 mmol, 1.1 equiv.). The reaction mixture was then stirred under reflux for 1.5 hours. The reaction mixture was then quenched with water, washed with a saturated solution of NaHCO3, extracted with DCM, and concentrated under reduced pressure. The crude product was purified by flash column chromatography (DCM / MeOH) to give 0.7 g (60% yield) of the desired product as a white solid: ESI(+)[M+H] + =438.6; 1 H NMR (300 MHz, DMSO-d6) δ 8.66 (d, J = 5.0 Hz, 1H), 8.40 (s, 1H), 6.83 (s, 1H), 3.25 - 3.09 (m, 1H), 2.98 (d, J = 4.9 Hz, 3H), 2.71 (s, 3H), 2.21 (d, J = 10.3 Hz, 2H), 1.69 (d, J = 7.4 Hz, 6H), 1.41 (s, 9H).

[0146] Step 5: tert-butyl N-methyl-N-[(1r,4r)-4-[5-(6-{3-cyanopyrrolo[1,2-b]pyridazin-7-yl}-4-(methylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl]cyclohexyl]carbamate. tert-Butyl N-methyl-N-[(1r,4r)-4-{5-[6-chloro-4-(methylamino)pyridin-3-yl]-1,3,4-thiadiazol-2-yl}cyclohexyl]carbamate (0.7 g, 1.6 mmol, 1.0 equiv.), 7-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile (0.6 g, 2.23 mmol, 1.4 equiv.), and Pd(dppf)Cl 2· To a solution of CHCl (0.328 g, 0.4 mmol, 0.25 equiv.) in dioxane (30 mL) was added 2 M KCO (1.6 mL, 3.2 mmol, 2.0 equiv.). The solution was degassed with argon for 2-3 min, then heated to 120 °C and stirred overnight. UPLC showed complete conversion of the starting material. The resulting solution was diluted with MeOH, filtered through Celite, and concentrated to dryness. The crude material was purified by chromatography eluting with DCM:MeOH (0-10%) to give 0.7 g (80% yield) of the desired product: ESI (+) [M+H] + =546.1; 1 H NMR (300 MHz, DMSO-d6) δ 8.85 (d, J = 2.2 Hz, 1H), 8.74 (d, J = 2.2 Hz, 1H), 8.71 - 8.58 (m, 2H), 8.19 (s, 1H), 7.88 (d, J = 4.8 Hz, 1H), 7.13 (d, J = 4.8 Hz, 1H), 3.24 - 3.15 (m, 1H), 3.09 (d, J = 4.9 Hz, 3H), 2.71 (s, 3H), 2.30 - 2.12 (m, 2H), 1.76 - 1.53 (m, 6H), 1.42 (s, 9H).

[0147] Step 6: 7-[4-(methylamino)-5-{5-[(1r,4r)-4-(methylamino)cyclohexyl]-1,3,4-thiadiazol-2-yl}pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile. In a sealed vial, tert-butyl N-methyl-N-[(1r,4r)-4-[5-(6-{3-cyanopyrrolo[1,2-b]pyridazin-7-yl}-4-(methylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl]cyclohexyl]carbamate (0.67 g, 1.23 mmol, 1.0 equiv.) was dissolved in hexafluro-2-propanol (4.0 ml, 30.0 equiv.) and irradiated by microwave at 150 °C for 2 h. UPLC indicated complete deprotection of the starting material. Evaporation of the solvent to dryness afforded 0.54 g of the desired product (99% yield) as a yellow solid: LCMS: ESI(+) [M+H] + =444.97; 1 H NMR (300 MHz, DMSO-d6) δ 8.84 (d, J = 2.3 Hz, 1H), 8.73 (d, J = 2.2 Hz, 1H), 8.68 - 8.47 (m, 2H), 8.18 (s, 1H), 7.88 (d, J = 4.8 Hz, 1H), 7.13 (d, J = 4.8 Hz, 1H), 3.20 - 3.10 (m, 1H), 3.09 (d, J = 4.8 Hz, 3H), 2.36 - 2.26 (m, 4H), 2.20 - 2.08 (m, 2H), 2.07 - 1.96 (m, 2H), 1.70 - 1.49 (m, 3H), 1.33 - 1.11 (m, 2H). BB19: 7-[5-(5-{3,8-diazabicyclo[3.2.1]octan-3-yl}-1,3,4-thiadiazol-2-yl)-4-(methylamino)pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile [ka]

[0148] Step 1: tert-Butyl 3-(5-bromo-1,3,4-thiadiazol-2-yl)-3,8-diazabicyclo[3.2.1]octane-8-carboxylate. A stirred suspension of 2,5-dibromo-1,3,4-thiadiazole (1.05 g, 4.305 mmol, 1.0 equiv.), 8-Boc-3,8-diaza-bicyclo[3.2.1]octane (1.005 g, 4.734 mmol, 1.1 equiv.), and N,N-diisopropylethylamine (1.125 mL, 6.459 mmol, 1.5 equiv.) in dioxane (21.53 mL, 0.2 M) was heated at 120° C. for 1 h. The reaction mixture was diluted with water and extracted with DCM, and the organic phase was concentrated onto silica gel. The crude material was purified by flash chromatography using a gradient of EtOAc / hexanes to give the title compound as a yellow oil (0.819 g, 2.182 mmol, 71%): ESI(+) [M+H] + =337.3; 1 H NMR (300 MHz, Chloroform-d) δ 4.37 (s, 2H), 3.72 - 3.26 (m, 4H), 2.03 (m, 2H), 1.82 (m, 2H), 1.50 (d, J = 0.8 Hz, 9H).

[0149] Step 2: 7-[4-(methylamino)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile. 7-[5-Bromo-4-(methylamino)pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile (1.5 g, 4.57 mmol, 1.0 equiv.) was dissolved in dioxane (25 mL, 0.18 M) in a sealed reaction vessel, followed by the addition of bis(pinacolato)diboron (1.39 g, 5.49 mmol, 1.2 equiv.) and KOAc (1.39 g, 14.17 mmol, 3.1 equiv.). Argon was bubbled through the solution for several minutes, and Pd(dppf)Cl2 was added. *DCM (0.373 g, 0.46 mmol, 0.1 equiv) was added, followed by repeated aeration. The reaction mixture was then transferred to a preheated oil bath and stirred at 90 °C overnight. The reaction mixture was filtered through Celite and evaporated to dryness. The crude material was used in the next step without further purification.

[0150] Step 3: tert-Butyl 3-[5-(6-{3-cyanopyrrolo[1,2-b]pyridazin-7-yl}-4-(methylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl]-3,8-diazabicyclo[3.2.1]octane-8-carboxylate. To a solution of 7-[4-(methylamino)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile (0.58 g, 1.55 mmol, 1.0 equiv.), tert-butyl 3-(5-bromo-1,3,4-thiadiazol-2-yl)-3,8-diazabicyclo[3.2.1]octane-8-carboxylate (0.638 g, 1.70 mmol, 1.1 equiv.) in dioxane (40 mL, 0.04 M) was added CsCO (1.26 g, 3.86 mmol, 2.5 equiv.) and Pd(OAc) (0.069 g, 0.309 mmol, 0.2 equiv.). Argon was bubbled through the reaction for several minutes, and then Xantphos (0.358 g, 0.618 mmol, 0.4 equiv) was added. The solution was degassed with argon for 2-3 minutes, then heated to 120 °C and stirred overnight. The reaction mixture was filtered through Celite and evaporated to dryness. The crude material was purified three times by chromatography eluting with DCM:MeOH (0-10%). Repurification of the major fraction by pTLC DCM:MeOH (0-10%) gave 0.190 g (23% yield) of the desired product after trituration with EtO: ESI (+) [M+H]. + =544.77; 1H NMR (300 MHz, DMSO-d6) δ: 8.83 (1 H, d, J 2.2), 8.72 (1 H, d, J 2.3), 8.51 - 8.43 (2 H, m), 8.14 (1 H, s), 7.85 (1 H, d, J 4.8), 7.12 (1 H, d, J 4.8), 4.28 (2 H, s), 3.67 (2 H, d, J 11.8), 3.37 (2 H, d), 3.06 (3 H, d, J 4.9), 1.91 (2 H, d, J 6.3), 1.75 (2 H, d, J 7.4), 1.44 (9 H, s).

[0151] Step 4: 7-[5-(5-{3,8-diazabicyclo[3.2.1]octan-3-yl}-1,3,4-thiadiazol-2-yl)-4-(methylamino)pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile. In a pressure vessel, tert-butyl 3-[5-(6-{3-cyanopyrrolo[1,2-b]pyridazin-7-yl}-4-(methylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl]-3,8-diazabicyclo[3.2.1]octane-8-carboxylate (0.120 g, 0.22 mmol, 1.0 equiv.) was added to hexafluoro-2-propanol (0.7 mL) and irradiated in a microwave at 150 °C for 2.5 hours. Evaporation of the solvent to dryness and trituration with Et2O gave 0.080 g (82% yield) of the desired product: ESI(+)[M+H] + =444.05; 1 H NMR (300 MHz, DMSO-d6) δ: 8.83 (1 H, d, J 2.3), 8.72 (1 H, d, J 2.2), 8.52 - 8.44 (2 H, m), 8.13 (1 H, s), 7.85 (1 H, d, J 4.8), 7.12 (1 H, d, J 4.8), 3.61 - 3.46 (4 H, m), 3.29 (3 H, s), 3.06 (3 H, m,), 1.70 (4 H, dd, J 9.8, 6.7). BB20: 7-(4-(methylamino)-5-(5-(8-(piperidin-4-yl)-3,8-diazabicyclo[3.2.1]octan-3-yl)-1,3,4-thiadiazol-2-yl)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile [ka]

[0152] Step 1: tert-Butyl 4-(3-(5-bromo-1,3,4-thiadiazol-2-yl)-3,8-diazabicyclo[3.2.1]octan-8-yl)piperidine-1-carboxylate. tert-Butyl 3-(5-bromo-1,3,4-thiadiazol-2-yl)-3,8-diazabicyclo[3.2.1]octane-8-carboxylate (600 mg, 1.6 mmol) (see Step 1 of BB19) was subjected to 1:4 TFA / DC (0.1 M) for 2 h, then it was concentrated. The crude material was dissolved in DCE and TEA, and then tert-butyl 4-oxopiperidine-1-carboxylate (1 equivalent) was added. After 10 min, STAB (2.2 equivalents) was added, and the reaction was stirred overnight. The reaction mixture was partitioned between DCM and water. The organic layer was separated, dried over magnesium sulfate, and then concentrated. Chromatography (0-10% methanol in DCM) afforded the desired product (500 mg, 68%). Completion of this synthetic route was carried out as previously described for steps 2 and 3 of BB6. LCMS: C 27 H 30 N 10 S Theoretical value: 526.2, Measured value: m / z = 527.6 [M+H] + . BB21: 7-[5-(5-{2,7-diazaspiro[3.5]nonan-2-yl}-1,3,4-thiadiazol-2-yl)-4-(methylamino)pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile [ka]

[0153] Step 1: tert-Butyl 2-(5-bromo-1,3,4-thiadiazol-2-yl)-2,7-diazaspiro[3.5]nonane-7-carboxylate. A stirred suspension of 2,5-dibromo-1,3,4-thiadiazole (970 mg, 3.98 mmol, 1.0 equiv), tert-butyl 2,7-diazaspiro[3.5]nonane-7-carboxylate (990 mg, 4.37 mmol, 1.1 equiv), and DIPEA (1.038 mL, 4.61 mmol, 1.5 equiv) in dioxane (15 mL, 0.21 M) was heated at 120° C. for 1 h. The reaction mixture was diluted with water (10 mL) and extracted with DCM (20 mL). The crude material was purified by flash chromatography eluting with hexanes: EtOAc to give 1.54 g of a yellow oil (96% yield): ESI(+) [M+H] + =391.31 1 H NMR (300 MHz, DMSO-d6) δ 3.83 (s, 4H), 3.31 - 3.21 (m, 4H), 1.75 - 1.62 (m, 4H), 1.39 (s, 9H).

[0154] Step 2: 7-[4-(methylamino)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile. 7-[5-Bromo-4-(methylamino)pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile (1.5 g, 4.57 mmol, 1.0 equiv.) was dissolved in dioxane (25 mL) in a pressure vessel, followed by the addition of bis(pinacolato)diboron (1.39 g, 5.49 mmol, 1.2 equiv.) and KOAc (0.89 g, 9.14 mmol, 2.0 equiv.). Argon was bubbled through the solution for 7 min, and Pd(dppf)Cl2 was added. *DCM (0.375 g, 0.457 mmol, 0.1 equiv) was added, followed by repeated aeration. The reaction mixture was then transferred to a preheated oil bath and stirred at 90° C. overnight. UPLC indicated the formation of the product. The reaction mixture was filtered through a celite cake and evaporated to dryness. The crude material was used in the next step without further purification. ESI(+)[M+H] + =294.2

[0155] Step 3: tert-Butyl 2-[5-(6-{3-cyanopyrrolo[1,2-b]pyridazin-7-yl}-4-(methylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl]-2,7-diazaspiro[3.5]nonane-7-carboxylate. To a solution of tert-butyl 2-(5-bromo-1,3,4-thiadiazol-2-yl)-2,7-diazaspiro[3.5]nonane-7-carboxylate (1.377 g, 2.57 mmol, 1.0 equiv.) and 7-[4-(methylamino)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile (1.0 g, 2. mmol, 1.0 equiv.) in dioxane (13 ml, 0.2 M) was added cesium carbonate (2.09 g, 6.42 mmol, 2.5 equiv.) and palladium acetate (0.115 g, 0.51 mmol, 0.2 equiv.) in a pressure vessel. Argon was bubbled through the reaction for 7 minutes, then Xantphos (0.59 g, 1.03 mmol, 0.4 equiv) was added. The solution was degassed with argon for 2-3 minutes, then heated to 120°C and stirred overnight. UPLC showed product formation. The reaction mixture was filtered through a Celite cake and evaporated to dryness. The crude material was purified by chromatography eluting with DCM:MeOH (0-10%) to give 0.415 g (29% yield) of the desired product. ESI (+) [M+H] + =558.8; 1H NMR (300 MHz, DMSO-d6) δ 8.83 (d, J = 2.2 Hz, 1H), 8.73 (d, J = 2.2 Hz, 1H), 8.48 (s, 2H), 8.14 (s, 1H), 7.85 (d, J = 4.8 Hz, 1H), 7.12 (d, J = 4.8 Hz, 1H), 3.91 (s, 4H), 3.06 (d, J = 4.8 Hz, 3H), 1.75 (t, J = 5.6 Hz, 4H), 1.40 (s, 9H).

[0156] Step 4: 7-[5-(5-{2,7-diazaspiro[3.5]nonan-2-yl}-1,3,4-thiadiazol-2-yl)-4-(methylamino)pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile. In a sealed reaction vessel, tert-butyl 2-[5-(6-{3-cyanopyrrolo[1,2-b]pyridazin-7-yl}-4-(methylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl]-2,7-diazaspiro[3.5]nonane-7-carboxylate (0.2 g, 0.359 mmol, 1.0 equiv) was dissolved in hexafluoro-2-propanol (1.13 mL, 30.0 equiv) and heated in a microwave at 150° C. for 2 hours. UPLC showed complete deprotection of the starting material. The solvent was evaporated to dryness and the solid was triturated with EtO to give 146 mg (87% yield) of the desired product as a yellow solid. LCMS: ESI(+) [M+H] + =458.08; 1 H NMR (300 MHz, DMSO-d6) δ 8.83 (d, J = 2.2 Hz, 1H), 8.72 (d, J = 2.2 Hz, 1H), 8.47 (s, 2H), 8.13 (s, 1H), 7.85 (d, J = 4.8 Hz, 1H), 7.12 (d, J = 4.8 Hz, 1H), 3.86 (s, 4H), 3.06 (d, J = 4.8 Hz, 3H), 2.63 (t, J = 5.4 Hz, 4H), 1.87 - 1.60 (m, 4H). BB22: 7-(5-(5-([4,4'-bipiperidin]-1-yl)-1,3,4-thiadiazol-2-yl)-4-(methylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile [ka]

[0157] BB22 was synthesized following the same route as BB10, except that tert-butyl [4,4'-bipiperidine]-1-carboxylate was used as the amine in step 1. LCMS: C 26 H 29 N9S Theoretical value: 499.2, Measured value: m / z = 500.4 [M+H] + . BB23: 7-(4-(methylamino)-5-(5-(4-(piperazin-1-yl)piperidin-1-yl)-1,3,4-thiadiazol-2-yl)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile [ka]

[0158] BB23 was synthesized following the same route as BB10, except that tert-butyl 4-(piperidin-4-yl)piperazine-1-carboxylate was used as the amine in step 1. LCMS: C 25 H 28 N 10 S Theoretical value: 500.2, Measured value: m / z = 501.4 [M+H] + . BB24: 7-[4-(methylamino)-5-{5-[(1r,3r)-3-aminocyclobutyl]-1,3,4-thiadiazol-2-yl}pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile [ka]

[0159] Step 1: tert-Butyl N-[3-({[6-chloro-4-(methylamino)pyridin-3-yl]formohydrazide}carbonyl)cyclobutyl]carbamate. To a solution of 6-chloro-4-(methylamino)pyridine-3-carbohydrazide (3.0 g, 19.93 mmol, 1.0 equiv.) and trans-3-((tert-butoxycarbonyl)amino)cyclobutanecarboxylic acid (3.54 g, 16.48 mmol, 1.1 equiv.) in DMF (38 mL) was added DIPEA (7.81 mL, 44.86 mmol, 3.0 equiv.) and HATU (6.82 g, 17.94 mmol, 1.2 equiv.), and the mixture was stirred at 25° C. for 1 h. TLC (dichloromethane:methanol=10:1) showed the consumption of the starting material and the formation of a new spot. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with water, brine, dried over Na2SO4, and concentrated to give the crude product. The crude product was purified by chromatography eluting with DCM:MeOH (0-10%) to give 4.73 g (80% yield) of the desired product. ESI (+) [M+H] + =400.5; 1 H NMR (300 MHz, DMSO-d6) δ 10.32 (s, 1H), 9.78 (s, 1H), 8.34 (s, 1H), 8.10 (d, J = 5.1 Hz, 1H), 7.20 (d, J = 8.0 Hz, 1H), 6.67 (s, 1H), 4.13 (q, J = 7.9 Hz, 1H), 2.96 - 2.88 (m, 1H), 2.83 (d, J = 4.9 Hz, 3H), 2.40 - 2.28 (m, 2H), 2.20 - 2.08 (m, 2H), 1.37 (s, 9H).

[0160] Step 2: tert-Butyl N-[(1r,3r)-3-{5-[6-chloro-4-(methylamino)pyridin-3-yl]-1,3,4-thiadiazol-2-yl}cyclobutyl]carbamate. To a solution of tert-butyl N-[3-({[6-chloro-4-(methylamino)pyridin-3-yl]formohydrazide}carbonyl)cyclobutyl]carbamate (4.73 g, 1 mmol, 1.0 equiv) in toluene (94.0 mL, 0.13 M) was added Lawesson's reagent (5.28 g, 13.08 mmol, 1.1 equiv), and the mixture was stirred at 90 °C for 2 h. The reaction mixture was washed with NaHCO, extracted with DCM, concentrated, and purified by chromatography eluting with DCM:MeOH (0-10%) to give 3.9 g (50% yield) of the desired product in 60% purity. ESI(+)[M+H] + =298.5; 1 H NMR (300 MHz, DMSO-d6) δ 8.68 - 8.60 (m, 1H), 8.39 (s, 1H), 7.39 (d, J = 8.0 Hz, 1H), 6.83 (s, 1H), 4.36 - 4.16 (m, 1H), 2.99 (d, 3H), 2.59 - 2.51 (m, 4H), 1.38 (s, 9H).

[0161] Step 3: tert-Butyl N-[(1r,3r)-3-[5-(6-{3-cyanopyrrolo[1,2-b]pyridazin-7-yl}-4-(methylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl]cyclobutyl]carbamate. To a solution of tert-butyl N-[(1r,3r)-3-{5-[6-chloro-4-(methylamino)pyridin-3-yl]-1,3,4-thiadiazol-2-yl}cyclobutyl]carbamate (1.0 g, 1.51 mmol, 1.0 equiv.), {3-cyanopyrrolo[1,2-b]pyridazin-7-yl}boronic acid (0.496 g, 2.12 mmol, 1.4 equiv.), and Pd(dppf)Cl.CH.sub.2Cl.sub.2 (0.310 g, 0.379 mmol, 0.25 equiv.) in anhydrous dioxane (19 mL, 0.08 M) was added 2 M K.sub.2CO.sub.3 (1.51 mL, 3.03 mmol, 2.0 equiv.) in a pressure vessel. The solution was degassed with argon for 2-3 minutes, then heated to 120 °C in an oil bath, and stirred overnight. LCMS showed complete conversion of the starting material. The resulting solution was diluted with MeOH, washed through a Celite cake, and concentrated to dryness. The crude material was purified by chromatography eluting with DCM:MeOH (0-10%), then pPTLC DCM:MeOH 4%, to give 190 mg (25% yield) of the desired product. ESI (+) [M+H] + =503.8; 1 H NMR (300 MHz, DMSO-d6) δ 8.85 (d, J = 2.2 Hz, 1H), 8.75 (d, J = 2.3 Hz, 1H), 8.73 - 8.52 (m, 1H), 8.21 (s, 1H), 7.89 (d, J = 4.8 Hz, 1H), 7.40 (d, J = 8.0 Hz, 1H), 7.13 (d, J = 4.8 Hz, 1H), 4.35 - 4.23 (m, 1H), 4.00 - 3.87 (m, 1H), 3.10 (d, J = 4.9 Hz, 3H), 2.63 - 2.52 (m, 4H), 1.39 (s, 9H).

[0162] Step 4: 7-[4-(methylamino)-5-{5-[(1r,3r)-3-aminocyclobutyl]-1,3,4-thiadiazol-2-yl}pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile. tert-Butyl N-[(1r,3r)-3-[5-(6-{3-cyanopyrrolo[1,2-b]pyridazin-7-yl}-4-(methylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl]cyclobutyl]carbamate (0.17 g, 0.338 mmol, 1.0 equiv.) was dissolved in hexafluoro-2-propanol (1.1 ml, 30.0 equiv.) in a sealed reaction vessel and placed in a microwave at 150 °C for 2 hours. LCMS indicated complete deprotection of the starting material. The solvent was evaporated to dryness and the solid was triturated with Et2O to give 101 mg (70% yield) of the desired product. LCMS: ESI(+) [M+H] + =403.03;1H NMR (300 MHz, DMSO-d6) δ 8.83 (d, J = 2.3 Hz, 1H), 8.73 (d, J = 2.2 Hz, 1H), 8.67 - 8.56 (m, 2H), 8.18 (s, 1H), 7.87 (d, J = 4.8 Hz, 1H), 7.12 (d, J = 4.8 Hz, 1H), 3.89 (dq, J = 8.8, 4.3, 3.9 Hz, 1H), 3.64 (q, J = 7.4 Hz, 1H), 3.09 (d, J = 4.8 Hz, 3H), 2.59 - 2.52 (m, 2H), 2.34 - 2.18 (m, 2H). BB25: 7-[4-(isopropylamino)-5-{5-[4-(piperidin-4-ylmethyl)piperazin-1-yl]-1,3,4-thiadiazol-2-yl}pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile [ka]

[0163] BB4 (105 mg, 0.23 mmol) and tert-butyl 4-formylpiperidine-1-carboxylate (50 mg, 0.23 mmol) were combined in DCE (0.1 M), followed by the addition of TEA (5 equiv). After 5 min, STAB (124 mg, 2.5 equiv) was added in one portion. After stirring overnight, the reaction mixture was partitioned between DCM and water. The organic layer was separated, dried over magnesium sulfate, and concentrated. The crude material was subjected to 4 M dioxane for 3 h and then concentrated by rotary evaporation. Reverse-phase ISCO (C18 column, 0-100% acetonitrile in water) afforded a yellow solid (50 mg, 39%). LCMS: C 28 H 34 N 10 S Theoretical value: 542.3, Measured value: m / z = 543.5 [M+H] + . BB26: 7-(5-(5-((1r,4r)-4-(ethylamino)cyclohexyl)-1,3,4-thiadiazol-2-yl)-4-(methylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile [ka] BB26 was synthesized in a similar manner to BB18, replacing methyl iodide with ethyl iodide in step 1, to give the title compound. LCMS:C 24 H 26 N8S Theoretical value: 458.2, Measured value: m / z = 459.0 [M+H] + B. General Scheme for Preparing LHM Building Blocks CRBN-targeting LHMs can generally be prepared according to Scheme B1. [ka]

[0164] In Scheme B1, a functionalized thalidomide (e.g., at the 4- or 5-position of the phthalimide ring) is first linked to a linker precursor. The linker precursor (amino ester) contains "Linker A" (representing one or more linker segments, including L5), and two reactive end groups, an amine and a protected carboxylic acid in ester form. Step 1 describes the initial coupling step in more detail using an exemplary amino ester linker precursor.

[0165] Step 1: A mixture of 2-(2,6-dioxopiperidin-3-yl)-4-fluoro-2,3-dihydro-1H-isoindole-1,3-dione (0.26 mmol), amino ester (0.26 mmol), ethylbis(propan-2-yl)amine (0.52 mmol), and DMF (1 mL) was stirred overnight at 90° C. The mixture was cooled and purified by HPLC (5-95% MeCN in HO containing 0.1% TFA) to give the tert-butyl ester intermediate.

[0166] This tert-butyl ester intermediate is then hydrolyzed (see Step 2) to yield a CRBN-targeting LHM building block having a carboxylic acid-terminated "Linker A," which can be further reactively linked to another moiety.

[0167] Step 2: A mixture of tert-butyl 4-{[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl]amino}butanoate (0.10 mmol), CHCl (1 mL), and TFA (1 mL) was stirred at room temperature for 2 hours. The mixture was concentrated to give the carboxylic acid product.

[0168] Additional examples of building blocks for CRBN-targeting LHMs that can be prepared according to Scheme B1 are described below.

[0169] HCB1: 3-(2-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)ethoxy)propanoic acid. [ka]

[0170] Step 1 product: tert-butyl 3-[2-[[2-(2,6-dioxo-3-piperidyl)-1,3-dioxo-isoindolin-4-yl]amino]ethoxy]propanoate (1.8 g, 51.9%). LCMS; C 22 H 27 N3O7 theoretical value: 445, measured value: m / z = 468 [M + Na] + .

[0171] Step 2 product: 3-[2-[[2-(2,6-dioxo-3-piperidyl)-1,3-dioxo-isoindolin-4-yl]amino]ethoxy]propanoic acid (526 mg, 32%). LCMS; C 18 H 19 N3O7 theoretical value: 389, measured value: m / z = 390 [M+H] + .

[0172] HCB2: 3-(2-(2-(2-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)ethoxy)ethoxy)ethoxy)propanoic acid. [ka]

[0173] Step 1 product: tert-butyl 3-[2-[2-[2-[[2-(2,6-dioxo-3-piperidyl)-1,3-dioxoisoindolin-4-yl]amino]ethoxy]ethoxy]ethoxy]propanoate (1.6 g, 41%). LCMS; C 26 H 35 N3O9 theoretical value: 533, measured value: m / z = 534 [M+H] + .

[0174] Step 2 product: 3-[2-[2-[2-[[2-(2,6-dioxo-3-piperidyl)-1,3-dioxo-isoindolin-4-yl]amino]ethoxy]ethoxy]ethoxy]propanoic acid (1.2 g, 73.62%). LCMS; C 22 H 27 N3O9 theoretical value: 477, measured value: m / z = 478 [M+H] + . HCB3: 6-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)amino)hexanoic acid [ka] Step 1: tert-Butyl 6-{[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindol-5-yl]amino}hexanoate

[0175] To a mixture of 2-(2,6-dioxopiperidin-3-yl)-5-fluoroisoindole-1,3-dione (250 mg, 0.91 mmol), tert-butyl 6-aminohexanoate hydrochloride (203 mg, 0.91 mmol) in NMP (3 mL) was added N,N-diisopropylethylamine (0.6 mL) and heated to 85° C. overnight. The crude reaction mixture was purified by silica gel chromatography using EtOAc / hexanes (0-100%) to give tert-butyl 6-{[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindol-5-yl]amino}hexanoate (111 mg, 28%). LCMS: C 23 H 29 N3O6, theoretical value: 443.5, measured value: m / z = 444.4 [M+H] + . Step 2: 6-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)amino)hexanoic acid

[0176] To a solution of tert-butyl 6-{[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindol-5-yl]amino}hexanoate (111 mg, 0.25 mmol) in DCM was added TFA (0.5 mL). The reaction mixture was stirred at room temperature for 30 minutes, and then the reaction mixture was concentrated to give 6-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)amino)hexanoic acid (78 mg, 78%). 1 H NMR (500 MHz, DMSO-d6) δ 12.00 (s, 1H), 11.06 (s, 1H), 7.57 (d, J = 8.3 Hz, 1H), 7.11 (s, 1H), 6.95 (d, J = 2.1 Hz, 1H), 6.85 (dd, J = 8.4, 2.1 Hz, 1H), 5.04 (dd, J = 12.7, 5.4 Hz, 1H), 3.16 (q, J = 6.4 Hz, 2H), 2.23 (t, J = 7.4 Hz, 2H), 2.03 - 1.97 (m, 1H), 1.56 (dq, J = 14.8, 7.2 Hz, 4H), 1.39 (q, J = 7.9 Hz, 2H).LCMS:C 19 H 21 N3O6, theoretical value: 387.4, measured value: m / z = 388.4 [M+H] + . HCB4: (1s,3s)-3-(2-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)ethoxy)cyclobutane-1-carboxylic acid [ka] [ka]

[0177] Step-1: Synthesis of cis-tert-butyl-3-(prop-2-en-1-yloxy)cyclobutane-1-carboxylate: To a solution of cis-tert-butyl-3-hydroxycyclobutane-1-carboxylate (10.0 g, 58.06 mmol) in tetrahydrofuran (100 mL) was added dropwise t-BuOK (64 mL, 1 M in THF) at 0 °C under nitrogen and stirred for 10 minutes. 3-Bromoprop-1-ene (7.02 g, 58.03 mmol) was added dropwise to the above solution at 0 °C. The resulting mixture was stirred at room temperature for 16 hours. After the reaction was completed, the resulting solution was quenched by adding saturated aqueous NH4Cl solution. The aqueous phase was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography using 0-20% ethyl acetate in petroleum ether to give cis-tert-butyl-3-(prop-2-en-1-yloxy)cyclobutane-1-carboxylate (11.3 g, 92%) as a colorless oil. 1 H NMR (300 MHz, Chloroform-d) δ 6.10 - 5.85 (m, 1H), 5.33 - 5.10 (m, 2H), 3.95 - 3.75 (m, 3H), 2.60 - 2.36 (m, 3H), 2.29 - 2.07 (m, 2H), 1.44 (s, 9H).

[0178] Step-2: Synthesis of cis-tert-butyl-3-(2-oxoethoxy)cyclobutane-1-carboxylate: To a solution of cis-tert-butyl-3-(prop-2-en-1-yloxy)cyclobutane-1-carboxylate (1.0 g, 4.71 mmol) in dioxane (30 mL) and HO (15 mL), KOsO.2HO (86.28 mg, 0.24 mmol), 2,6-dimethylpyridine (1.01 g, 9.43 mmol), and NaIO (2.02 g, 9.42 mmol) were added. The resulting mixture was stirred at room temperature for 2 hours. After the reaction was completed, the mixture was diluted with water and extracted with ethyl acetate. The combined organic layer was washed with brine, dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The residue was purified by flash column chromatography using 0-50% ethyl acetate in petroleum ether to give cis-tert-butyl-3-(2-oxoethoxy)cyclobutane-1-carboxylate (505 mg, 50%) as a colorless oil. 1 H NMR (300 MHz, Chloroform-d) δ 9.72 (s, 1H), 6.97 (d, J = 7.8 Hz, 1H), 5.31 (s, 1H), 4.05 - 3.94 (m, 2H), 2.64 - 2.41 (m, 2H), 2.36 - 2.12 (m, 2H), 1.47 (s, 9H).

[0179] Step-3: Synthesis of cis-tert-butyl-3-[2-(benzylamino)ethoxy]cyclobutane-1-carboxylate: To a solution of cis-tert-butyl-3-(2-oxoethoxy)cyclobutane-1-carboxylate (2.0 g, 9.33 mmol) in methanol (20 mL) was added 1-phenylmethanamine (3.0 g, 28.00 mmol) and NaBH3CN (1.76 g, 28.00 mmol). The resulting solution was stirred at room temperature for 16 hours and then concentrated under vacuum. The residue was purified by flash column chromatography using 0-100% ethyl acetate in petroleum ether to give cis-tert-butyl-3-[2-(benzylamino)ethoxy]cyclobutane-1-carboxylate (1.1 g, 39%) as a colorless oil. MS (ESI) calculated (C 18 H 27 NO3) [M+H] + , 306.2; measured value 306.1.

[0180] Step-4: Synthesis of cis-tert-butyl-3-(2-aminoethoxy)cyclobutane-1-carboxylate: To a solution of cis-tert-butyl-3-[2-(benzylamino)ethoxy]cyclobutane-1-carboxylate (2.0 g, 6.55 mmol) in methanol (20 mL), Pd / C (10%, 0.5 g) was added. The resulting solution was stirred under hydrogen (40 atm) at room temperature for 72 hours. After the reaction was completed, the solid was filtered off, and the filtrate was concentrated in vacuo to give cis-tert-butyl-3-(2-aminoethoxy)cyclobutane-1-carboxylate (1.0 g, crude) as a colorless oil, which was used in the next step without further purification. MS (ESI) calculated (C 11 H 21 NO3) [M+H] + , 216.2; measured value 216.1.

[0181] Step-5: Synthesis of cis-tert-butyl-3-(2-[[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl]amino]ethoxy)cyclobutane-1-carboxylate: To a solution of cis-tert-butyl-3-(2-aminoethoxy)cyclobutane-1-carboxylate (1.0 g, 4.64 mmol) in N,N-dimethylformamide (10 mL), DIEA (6.0 g, 46.43 mmol) and 2-(2,6-dioxopiperidin-3-yl)-4-fluoro-2,3-dihydro-1H-isoindole-1,3-dione (6.72 g, 24.33 mmol) were added. The resulting solution was stirred at 90 ° C. for 4 hours. After the reaction was completed, the resulting solution was diluted with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, and concentrated in vacuo. The residue was purified by reverse-phase flash column chromatography using 0-100% acetonitrile in water to give cis-tert-butyl-3-(2-[[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl]amino]ethoxy)cyclobutane-1-carboxylate (250 mg, 11%) as a red solid. MS(ESI) calculated (C 24 H 29 N3O7)[M+H] + , 472.2; measured value 472.1.

[0182] Step 6: Synthesis of cis-3-(2-[[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl]amino]ethoxy)cyclobutane-1-carboxylic acid: To a solution of cis-tert-butyl-3-(2-[[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl]amino]ethoxy)cyclobutane-1-carboxylate (850 mg, 1.8 mmol) in dichloromethane (10 mL) was added trifluoroacetic acid (10 mL). The resulting solution was stirred at room temperature for 3 hours and then concentrated in vacuo. The residue was purified by reverse-phase flash column chromatography using 0-100% acetonitrile in water to give the crude product, which was purified using the following conditions [Column: Ultimate XB-NH2, 21.2 * Further purification by non-chiral preparative SFC using [250 mm; 5 μm; mobile phase A: CO 2 : 50, mobile phase B: MeOH—preparative: 50; flow rate: 40 mL / min; 220 nm] afforded cis-3-(2-[[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxo-2,3-dihydro-1H-isoindol-4-yl]amino]ethoxy)cyclobutane-1-carboxylic acid (359.1 mg, 37) as a yellow solid. MS(ESI) calculated (C 20 H 21 N3O7)[M+H] + , 416.4; measured value 416.2. 1 H NMR (400 MHz, DMSO-d6) δ 12.16 (s, 1H), 11.11 (s, 1H), 7.63 - 7.55 (m, 1H), 7.15 (d, J = 8.0 Hz, 1H), 7.05 (d, J = 8.0 Hz, 1H), 6.59 (t, J = 5.6 Hz, 1H), 5.12 - 5.03 (m, 1H), 3.96 - 3.84 (m, 1H), 3.59 - 3.40 (m, 4H), 2.98 - 2.82 (m, 1H), 2.64 - 2.52 (m, 3H), 2.48 - 2.37 (m, 2H), 2.08 - 1.91 (m, 3H).

[0183] Scheme B2 shows an alternative approach for preparing building blocks of CRBN-targeting LHMs. [ka]

[0184] Step 1: 2-(2,6-dioxopiperidin-3-yl)-5-fluoroisoindoline-1,3-dione. A mixture of 5-fluoro-1,3-dihydro-2-benzofuran-1,3-dione (5.0 g, 30.10 mmol), 3-aminopiperidine-2,6-dione hydrochloride (6.9 g, 42.14 mmol), and NaOAc (4.2 g, 51.17 mmol) in HOAc (50 mL) was stirred at 120° C. for 5 hours and then concentrated under vacuum. The residue was washed with water, and the solid was collected by filtration. The crude product was washed twice with water and twice with ethyl acetate and dried in an oven to give 2-(2,6-dioxopiperidin-3-yl)-5-fluoroisoindoline-1,3-dione (7.7 g, 92%) as a light brown solid. 1 H NMR (300 MHz, DMSO-d6) δ 11.16 (s, 1H), 8.03 - 8.00 (m, 1H), 7.87 - 7.85 (m, 1H), 7.75 - 7.70 (m, 1H), 5.19 - 5.15 (m, 1H), 2.94 - 2.86 (m, 1H), 2.63 - 2.48 (m, 2H), 2.12 - 2.06 (m, 1H).F NMR (300 MHz, DMSO-d6) δ -102.078.

[0185] Step 2: Amine substitution of aryl fluoride. To a solution of 2-(2,6-dioxopiperidin-3-yl)-5-fluoro-2,3-dihydro-1H-isoindole-1,3-dione (1.0 g, 3.62 mmol) in N-methylpyrrolidone (10 mL) was added amine (3.60 mmol) and DIEA (1.4 g, 10.83 mmol). The resulting solution was stirred at 80° C. for 16 hours. The reaction mixture was cooled to room temperature and purified by reverse-phase flash chromatography to give the corresponding final product.

[0186] Step 3: Oxidation of the alcohol to the aldehyde. To a mixture of the alcohol (1.06 mmol) in CHCl (10 mL) was added Dess-Martin periodinane (2.12 mmol). The mixture was stirred at room temperature for 1 hour. The mixture was purified by column chromatography to give the desired aldehyde.

[0187] Additional examples of building blocks for CRBN-targeting LHMs that can be prepared according to Scheme B2 are described below. HCB5: (3S)-1-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)pyrrolidine-3-carbaldehyde [ka]

[0188] Step 1: 2-(2,6-dioxopiperidin-3-yl)-5-fluoroisoindoline-1,3-dione. Same as Step 1 in Scheme B2.

[0189] Step 2: 2-(2,6-dioxopiperidin-3-yl)-5-((S)-3-(hydroxymethyl)pyrrolidin-1-yl)isoindoline-1,3-dione. 2-(2,6-Dioxopiperidin-3-yl)-5-fluoroisoindoline-1,3-dione was reacted with (S)-pyrrolidin-3-ylmethanol to give 2-(2,6-dioxopiperidin-3-yl)-5-((S)-3-(hydroxymethyl)pyrrolidin-1-yl)isoindoline-1,3-dione (643.1 mg, 33%) as a yellow solid. 1 H NMR (300 MHz, DMSO-d6) δ 11.08 (s, 1H), 7.64 (d, J = 8.4 Hz, 1H), 6.89 (d, J = 2.1 Hz, 1H), 6.80 (dd, J = 8.4, 2.1 Hz, 1H), 5.06 (dd, J = 12.9, 5.4 Hz, 1H), 4.78 (t, J = 5.4 Hz, 1H), 3.59 - 3.41 (m, 5H), 3.22 - 3.17 (m, 1H), 2.95 - 2.83 (m, 1H), 2.67 - 2.44 (m, 3H), 2.12 - 1.88 (m, 2H), 1.87 - 1.76 (m, 1H).MS(ESI) calculated value(C 18 H 19 N3O5)[M+H] + , 358.1; measured value 358.1.

[0190] Step 3: (3S)-1-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)pyrrolidine-3-carbaldehyde. To a mixture of 2-(2,6-dioxopiperidin-3-yl)-5-[(3S)-3-(hydroxymethyl)pyrrolidin-1-yl]isoindole-1,3-dione (258 mg, 0.72 mmol) in DCM (5 mL) was added 1,1-bis(acetyloxy)-3-oxo-1λ 5,2-Benzoiodaoxol-1-yl acetate (0.61 g, 1.44 mmol) was added. After 90 min, silica gel was added and the mixture was concentrated to dryness. The resulting powder was transferred to a loading cartridge, and the mixture was purified by flash chromatography on a 24 g column eluted with 0-100% ethyl acetate / hexanes to give (3S)-1-[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindol-5-yl]pyrrolidine-3-carbaldehyde (198 mg, 77%). LCMS C 18 H 17 N3O5 theoretical value: 355, measured value: m / z = 356 [M+H] + . HCB6: 3-{4-[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindol-5-yl]piperazin-1-yl}propanoic acid [ka]

[0191] Step 1: tert-Butyl 3-(4-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)piperazin-1-yl)propanoate. To tert-butyl 3-(piperazin-1-yl)propanoate (400.00 mg, 1.87 mmol) and 2-(2,6-dioxopiperidin-3-yl)-5-fluoroisoindole-1,3-dione (515.56 mg, 1.87 mmol) in NMP (10 mL) was added N,N-diisopropylethylamine (0.65 mL, 0.48 g, 3.73 mmol) and heated at 85-90° C. for 16 h. Partitioned between EtOAc / water (×2), then the organic layer was washed with brine, dried, and concentrated. Silica gel column purification using 10-100% EtOAc / hexanes gave 823 mg of the desired product. LCMS: C24H30N4O6, theoretical: 470.5, found: m / z = 471.8 [M+H] + .

[0192] Step 2: 3-{4-[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindol-5-yl]piperazin-1-yl}propanoic acid. tert-Butyl 3-{4-[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindol-5-yl]piperazin-1-yl}propanoate (820.00 mg, 1.74 mmol) was dissolved in trifluoroacetic acid (9.94 g, 87.14 mmol), and the TFA was evaporated after 1 hour. The product was lyophilized to dryness to give 3-{4-[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindol-5-yl]piperazin-1-yl}propanoic acid (722 mg, 100% yield). LCMS: C20H22N4O6, theoretical value: 414.4, observed value: m / z = 415.4 [M+H] + . HCB7: 2-(2-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)-2,7-diazaspiro[3.5]nonan-7-yl)acetic acid [ka]

[0193] Step 1: Benzyl 2-{2-[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindol-5-yl]-2,7-diazaspiro[3.5]nonan-7-yl}acetate. To a mixture of 2-(2,6-dioxopiperidin-3-yl)-5-fluoroisoindole-1,3-dione (70.00 mg, 0.25 mmol) and benzyl 2-{2,7-diazaspiro[3.5]nonan-7-yl}acetate (69.53 mg, 0.25 mmol) in NMP (2 mL) was added N,N-diisopropylethylamine (0.13 mL) and heated at 85° C. overnight. The crude mixture was purified by column chromatography eluting with EtOAc / hexanes (10-100%) to give benzyl 2-{2-[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindol-5-yl]-2,7-diazaspiro[3.5]nonan-7-yl}acetate (68 mg, 51%). LCMS C29 H 30 N4O6 theoretical value: 530, measured value: m / z = 532 [M+H] + .

[0194] Step 2: 2-(2-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)-2,7-diazaspiro[3.5]nonan-7-yl)acetic acid. To a solution of benzyl 2-{2-[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindol-5-yl]-2,7-diazaspiro[3.5]nonan-7-yl}acetate (68.00 mg, 0.13 mmol) in EtOH (5 mL) and DCM (2 mL) was added palladium on carbon (6 mg, 0.06 mmol). The reaction mixture was sparged with hydrogen and maintained under 1 atmosphere of hydrogen using a balloon and stirred at room temperature for 48 hours. The reaction mixture was filtered through a pad of Celite and concentrated to give benzyl 2-{2-[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindol-5-yl]-2,7-diazaspiro[3.5]nonan-7-yl}acetate (56 mg, 99%). LCMS C 22 H 24 N4O6 theoretical value: 440, measured value: m / z = 441 [M+H] + . HCB8: 2-(1-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)piperidin-4-yl)acetaldehyde [ka]

[0195] Step 1: 2-(2,6-dioxopiperidin-3-yl)-5-fluoroisoindoline-1,3-dione. Same as Step 1 in Scheme B2.

[0196] Step 2: 2-(2,6-dioxopiperidin-3-yl)-5-(4-(2-hydroxyethyl)piperidin-1-yl)isoindoline-1,3-dione. 2-(2,6-Dioxopiperidin-3-yl)-5-fluoroisoindoline-1,3-dione was reacted with 2-(piperidin-4-yl)ethan-1-ol to give 2-(2,6-dioxopiperidin-3-yl)-5-(4-(2-hydroxyethyl)piperidin-1-yl)isoindoline-1,3-dione (823 mg, 59%) as a yellow solid. 1 H NMR (300 MHz, DMSO-d6) δ11.09 (s, 1H), 7.65 (d, J = 8.4 Hz, 1H), 7.30 (d, J = 2.4 Hz, 1H), 7.23 (dd, J = 8.4, 2.4 Hz, 1H), 5.07 (dd, J = 12.6, 5.4 Hz, 1H), 4.40 (t, J = 5.1 Hz, 1H), 4.04 (d, J = 13.2 Hz, 2H), 3.64 - 3.40 (m, 2H), 3.09 - 2.79 (m, 3H), 2.70 - 2.51 (m, 2H), 2.07 - 1.94 (m, 1H), 1.77 - 1.66 (m, 3H), 1.41 - 1.34 (m, 2H), 1.24 - 1.12 (m, 2H).MS(ESI) calculated value (C 20 H 23 N3O5)[M+H] + , 386.2; measured value 386.1.

[0197] Step 3: 2-(1-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)piperidin-4-yl)acetaldehyde. According to Scheme B2, 2-(2,6-dioxopiperidin-3-yl)-5-(4-(2-hydroxyethyl)piperidin-1-yl)isoindoline-1,3-dione was oxidized to give the title compound. LCMS C 20 H 21 N3O5 theoretical value: 383, measured value: m / z = 384 [M+H] + . HCB9: 1-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)piperidine-4-carbaldehyde [ka]

[0198] Step 1: 2-(2,6-dioxopiperidin-3-yl)-5-fluoroisoindoline-1,3-dione. Same as Step 1 in Scheme B2.

[0199] Step 2: 2-(2,6-dioxopiperidin-3-yl)-5-(4-(hydroxymethyl)piperidin-1-yl)isoindoline-1,3-dione. 2-(2,6-Dioxopiperidin-3-yl)-5-fluoroisoindoline-1,3-dione was reacted with piperidin-4-ylmethanol to give 2-(2,6-dioxopiperidin-3-yl)-5-(4-(hydroxymethyl)piperidin-1-yl)isoindoline-1,3-dione (939 mg, 70%) as a yellow solid. 1 H NMR (300 MHz, DMSO-d6) δ 11.09 (s, 1H), 7.65 (d, J = 8.4 Hz, 1H), 7.30 (d, J = 2.4 Hz, 1H), 7.23 (dd, J = 8.4, 2.4 Hz, 1H), 5.07 (dd, J = 12.6, 5.4 Hz, 1H), 4.51 (t, J = 5.1 Hz, 1H), 4.07 (d, J = 13.2 Hz, 2H), 3.27 (t, J = 5.7 Hz, 2H), 2.99 - 2.80 (m, 3H), 2.62 - 2.55 (m, 2H), 2.17 - 1.95 (m, 1H), 1.76 - 1.67 (m, 3H), 1.24 - 1.12 (m, 2H).MS(ESI) calculated value (C 19 H 21 N3O5)[M+H] + , 372.1; measured value 372.2.

[0200] Step 3: 1-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)piperidine-4-carbaldehyde. According to Scheme B2, 2-(2,6-dioxopiperidin-3-yl)-5-(4-(hydroxymethyl)piperidin-1-yl)isoindoline-1,3-dione was oxidized to give 1-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)piperidine-4-carbaldehyde. LCMS C 19 H 19 N3O5 theoretical value: 369, measured value: m / z = 370 [M+H] + . HCB10: 1-[2-(2,6-dioxopiperidin-3-yl)-1-oxoisoquinolin-6-yl]piperidine-4-carbaldehyde [ka]

[0201] Step 1: Synthesis of 2-bromopentanedioic acid. To a solution of L-glutamic acid (100.0 g, 0.7 mol) and NaBr (244.7 g, 2.4 mol) in HBr (1 L, 40% in water) was added dropwise a solution of NaNO (84.4 g, 1.2 mol, in 200 mL of water) at 0 °C under a nitrogen atmosphere. The resulting solution was stirred at 0-5 °C for 2 h. The reaction was quenched by adding 30 mL of concentrated HSO at 0 °C and stirred for 10 min. The resulting mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous NaSO, and filtered. The filtrate was concentrated in vacuo to give 2-bromopentanedioic acid (51 g, crude) as a light brown oil, which was used in the next step without further purification.

[0202] Step 2: Synthesis of dimethyl 2-bromopentanedioate. To a solution of 2-bromopentanedioic acid (51.0 g, 241.69 mmol) in MeOH (500 mL) was added concentrated H2SO4 (10 mL, 187.60 mmol). The mixture was stirred at 80 °C for 3 hours and then concentrated in vacuo. The residue was diluted with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SO4, and filtered. The filtrate was concentrated in vacuo. The residue was purified by flash column chromatography using 0 to 30% ethyl acetate in petroleum ether to afford dimethyl 2-bromopentanedioate (36 g, 62%) as a pale yellow oil. 1H NMR (300 MHz, Chloroform-d) δ 4.38 (dd, J = 8.4, 5.7 Hz, 1H), 3.79 (s, 3H), 3.69 (s, 3H), 2.55 - 2.51 (m, 2H), 2.47 - 2.20 (m, 2H).

[0203] Step 3: Synthesis of tert-butyl 4-(hydroxymethyl)piperidine-1-carboxylate. To a mixture of piperidin-4-ylmethanol (5.0 g, 43.41 mmol) and EtN (5.3 g, 52.37 mmol) in THF (50 mL) was added dropwise a solution of BocO (10.4 g, 47.65 mmol in 10 mL of THF) at −5° C. The resulting mixture was warmed to room temperature and stirred for 16 hours. The solvent was removed in vacuo, and the residue was partitioned between ethyl acetate and water. The collected organic layer was washed with 5% aqueous HCl, water, and brine, dried over anhydrous NaSO, and filtered. The filtrate was concentrated in vacuo. The crude product was triturated with hexane to give tert-butyl 4-(hydroxymethyl)piperidine-1-carboxylate (7.7 g, 82%) as a white solid. MS(ESI) calculated value (C11H21NO3)[M+H] + , 216.2; measured value 216.0.

[0204] Step 4: Synthesis of tert-butyl 4-(benzyloxymethyl)piperidine-1-carboxylate. To a mixture of NaH (42.0 g, 1021.86 mmol, 60%) in THF (500 mL) was added dropwise a solution of tert-butyl 4-(hydroxymethyl)piperidine-1-carboxylate (100.0 g, 464.483 mmol, 500 mL of THF) at 0 °C and stirred at room temperature for 30 minutes under a nitrogen atmosphere. Next, benzyl bromide (174.8 g, 1021.88 mmol) was added dropwise to the above mixture at room temperature. The resulting solution was stirred at 80 °C for 2 hours under a nitrogen atmosphere. The reaction mixture was quenched by carefully adding saturated aqueous NH4Cl solution. The aqueous layer was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SO4, and filtered. The filtrate was concentrated in vacuo. The residue was purified by flash column chromatography using 0-10% ethyl acetate in petroleum ether to give tert-butyl 4-(benzyloxymethyl)piperidine-1-carboxylate (115.6 g, 81%) as a pale yellow oil. MS (ESI) calculated (C18H27NO3) [M+H] + , 306.2; measured value 306.0.

[0205] Step 5: Synthesis of 4-((benzyloxy)methyl)piperidine. A solution of tert-butyl 4-(benzyloxymethyl)piperidine-1-carboxylate (94.0 g, 307.2 mmol) in HCl (4 M in dioxane) (1000 mL) was stirred at room temperature for 2 hours. The solvent was removed in vacuo. The residue was partitioned between ethyl acetate and 10% aqueous potassium carbonate. The collected organic layer was dried over anhydrous NaSO and filtered. The filtrate was concentrated in vacuo to give 4-[(benzyloxy)methyl]piperidine (54.0 g, 85%) as a yellow oil. MS (ESI) calculated (C13H19NO) [M+H] + , 206.2; measured value 206.2.

[0206] Step 6: Synthesis of 6-(4-(benzyloxymethyl)piperidin-1-yl)isoquinolin-1(2H)-one. To a degassed solution of 6-bromo-2H-isoquinolin-1-one (4.0 g, 17.85 mmol) in t-amyl alcohol (50 mL) was added 4-[(benzyloxy)methyl]piperidine (4.4 g, 21.42 mmol), t-BuONa (5.2 g, 53.91 mmol), and RuPhos-PdCl-2nd G (1.39 g, 1.78 mmol). The mixture was stirred under a nitrogen atmosphere at 100° C. for 3 hours. The reaction mixture was quenched by adding saturated aqueous citric acid and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous NaSO, and filtered. The filtrate was concentrated in vacuo. The residue was purified by flash column chromatography using 0-10% methanol in dichloromethane to give 6-(4-(benzyloxymethyl)piperidin-1-yl)isoquinolin-1(2H)-one (5.5 g, 88%) as a brown solid. MS (ESI) calculated (C22H24N2O2) [M+H] + , 349.2; measured value 349.2.

[0207] Step 7: Synthesis of dimethyl 2-(6-(4-(benzyloxymethyl)piperidin-1-yl)-1-oxoisoquinolin-2(1H)-yl)pentanedioate. To a solution of 6-(4-(benzyloxymethyl)piperidin-1-yl)isoquinolin-1(2H)-one (6.2 g, 17.79 mmol) in DMF (60 mL) was added dimethyl 2-bromopentanedioate (5.0 g, 20.91 mmol) and CsCO (17.4 g, 53.40 mmol). The resulting mixture was stirred under a nitrogen atmosphere at 100° C. for 16 hours. The mixture was diluted with saturated aqueous citric acid solution and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous NaSO, and filtered. The filtrate was concentrated in vacuo to give dimethyl 2-(6-(4-(benzyloxymethyl)piperidin-1-yl)-1-oxoisoquinolin-2(1H)-yl)pentanedioate (6 g, crude) as a brown oil, which was used in the next step without further purification. MS (ESI) calculated (C29H34N2O6) [M+H] + , 507.2; measured value 507.2.

[0208] Step 8: Synthesis of 2-(6-(4-(benzyloxymethyl)piperidin-1-yl)-1-oxoisoquinolin-2(1H)-yl)pentanedioic acid: To a solution of 1,5-dimethyl 2-(6-[4-[(benzyloxy)methyl]piperidin-1-yl]-1-oxoisoquinolin-2-yl)pentanedioate (20.0 g, 39.48 mmol) in MeOH (80 mL), THF (80 mL), and HO (80 mL) was added LiOH (5.67 g, 236.87 mmol). The mixture was stirred at room temperature for 16 hours. The organic solvent was removed in vacuo, and the residue was diluted with water and extracted with ethyl acetate. The collected aqueous layer was acidified to pH 5-6 with citric acid and extracted with ethyl acetate. The combined organic layer was washed with brine, dried over anhydrous NaSO, and filtered. The filtrate was concentrated in vacuo to give 2-(6-(4-(benzyloxymethyl)piperidin-1-yl)-1-oxoisoquinolin-2(1H)-yl)pentanedioic acid (15 g, crude) as a brown oil, which was used in the next step without further purification. MS (ESI) calculated (C27H30N2O6) [M+H] + , 479.2; measured value 479.0.

[0209] Step 9: Synthesis of 3-(6-(4-(benzyloxymethyl)piperidin-1-yl)-1-oxoisoquinolin-2(1H)-yl)piperidine-2,6-dione. To a solution of 2-(6-(4-(benzyloxymethyl)piperidin-1-yl)-1-oxoisoquinolin-2(1H)-yl)pentanedioic acid (1.60 g, 3.34 mmol) in NMP (15 mL) was added urea (2.0 g, 33.30 mmol). Under a nitrogen atmosphere, the mixture was stirred at 180° C. for 4 hours. The resulting mixture was cooled to room temperature and diluted with water. The mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous NaSO, and filtered. The filtrate was concentrated in vacuo. The residue was purified by reverse-phase flash column chromatography using 5–65% acetonitrile in water to give 3-(6-(4-(benzyloxymethyl)piperidin-1-yl)-1-oxoisoquinolin-2(1H)-yl)piperidine-2,6-dione (350 mg, 22%) as an off-white solid. MS (ESI) calculated (C27H29N3O4) [M+H] + , 460.2; measured value 460.2.

[0210] Step 10: Synthesis of 3-(6-(4-(hydroxymethyl)piperidin-1-yl)-1-oxoisoquinolin-2(1H)-yl)piperidine-2,6-dione. To a solution of 3-(6-(4-(benzyloxymethyl)piperidin-1-yl)-1-oxoisoquinolin-2(1H)-yl)piperidine-2,6-dione (1.8 g, 3.91 mmol) in THF (60 mL) was added Pd(OH) / C (10%, 1.8 g) and cyclohexene (3.2 g, 38.96 mmol). The mixture was stirred at 80° C. under a nitrogen atmosphere for 24 hours. Upon completion of the reaction, the solid was filtered off, and the filtrate was concentrated in vacuo. The residue was purified by high-pressure flash column chromatography using the following conditions: [column, C18 silica gel; mobile phase, MeCN (0.1% NH4HCO3) in water, gradient from 15% to 40% in 30 min; detector, UV 254 nm] to give 3-(6-(4-(hydroxymethyl)piperidin-1-yl)-1-oxoisoquinolin-2(1H)-yl)piperidine-2,6-dione (800 mg, 55%) as an off-white solid. 1 H NMR (300 MHz, DMSO-d6) δ 10.72 (s, 1H), 7.94 (d, J = 9.0 Hz, 1H), 7.23 (d, J = 7.5 Hz, 1H), 7.14 (dd, J = 9.0, 2.4 Hz, 1H), 6.92 (d, J = 2.4 Hz, 1H), 6.44 (d, J = 7.5 Hz, 1H), 5.40 (s, 1H), 4.47 (t, J = 5.1 Hz, 1H), 3.97 - 3.94 (m, 2H), 3.27 - 3.24 (m, 2H), 2.85 - 2.78 (m, 3H), 2.58 - 2.52 (m, 2H), 1.98 - 1.94 (m, 1H), 1.81 - 1.67 (m, 2H), 1.65 - 1.59 (m, 1H), 1.26 - 1.12 (m, 2H).MS(ESI) calculated value (C20H23N3O4)[M+H] + , 370.2; measured value, 370.3.

[0211] Step 11: 1-[2-(2,6-dioxopiperidin-3-yl)-1-oxoisoquinolin-6-yl]piperidine-4-carbaldehyde. 3-{6-[4-(hydroxymethyl)piperidin-1-yl]-1-oxoisoquinolin-2-yl}piperidine-2,6-dione (150.00 mg, 0.41 mmol) was dissolved in CHCl (2 mL) and 1,1-bis(acetyloxy)-3-oxo-1λ 5 ,2-Benzoiodaoxol-1-yl acetate (172 mg, 0.41 mmol) was added in one portion at room temperature. After 5 h, the reaction mixture was diluted with NaHCO3 (2 mL of saturated aqueous solution), Na2S2O3 (saturated aqueous solution) was added, and the mixture was stirred for 30 min. The organic phase was removed. The aqueous layer was extracted (2 × 20 mL of CHCl2), and the combined organic phases were dried (Na2SO4), filtered, and concentrated. Purification by silica gel column chromatography (2-6% MeOH / CHCl2) gave 1-[2-(2,6-dioxopiperidin-3-yl)-1-oxoisoquinolin-6-yl]piperidine-4-carbaldehyde (120 mg, 80%). LCMS C 20 H 21 N3O4 theoretical value: 367.2, measured value: m / z = 368.4 [M+H] + . HCB11: rac-(R)-1-(4-(1-(2,6-dioxopiperidin-3-yl)-4-methyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-3-yl)phenyl)piperidine-4-carbaldehyde [ka]

[0212] Step 1: Synthesis of methyl 4-(4-(hydroxymethyl)piperidin-1-yl)benzoate. To a solution of methyl 4-fluorobenzoate (25.0 g, 162.190 mmol) in DMF (250 mL) was added piperidin-4-ylmethanol (18.6 g, 162.18 mmol) and K2CO3 (44.8 g, 324.38 mmol). The resulting solution was stirred at 120 °C for 16 h. Upon completion of the reaction, the reaction mixture was cooled to room temperature and quenched by adding water. The resulting mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SO4, and filtered. The filtrate was concentrated under vacuum. The residue was purified by silica gel column chromatography using 0-50% ethyl acetate in petroleum ether to give methyl 4-(4-(hydroxymethyl)piperidin-1-yl)benzoate (14 g, 34%) as a white solid. MS (ESI) calculated value (C 14 H 19 NO3) [M+H] + , 250.1; measured value 250.0.

[0213] Step 2: Synthesis of methyl 4-(4-((tert-butyldimethylsilyloxy)methyl)piperidin-1-yl)benzoate. To a solution of methyl 4-(4-(hydroxymethyl)piperidin-1-yl)benzoate (40.0 g, 160.44 mmol) in DMF (400 mL) was added imidazole (21.8 g, 320.88 mmol), DMAP (1.9 g, 16.04 mmol), and t-butyldimethylchlorosilane (29.0 g, 192.53 mmol). The resulting mixture was stirred at room temperature under a nitrogen atmosphere for 3 hours. The reaction mixture was quenched by adding water and extracted with ethyl acetate. The combined organic layers were washed with water and brine, dried over anhydrous NaSO, and filtered. The filtrate was concentrated in vacuo. The residue was purified by silica gel column chromatography using 0-20% ethyl acetate in petroleum ether to give methyl 4-(4-((tert-butyldimethylsilyloxy)methyl)piperidin-1-yl)benzoate (35.0 g, 60%) as a white solid. MS(ESI) calculated (C 20 H33 NO3Si)[M+H] + , 364.2; measured value 364.2.

[0214] Step 3: Synthesis of 4-(4-((tert-butyldimethylsilyloxy)methyl)piperidin-1-yl)benzohydrazide. To a solution of methyl 4-(4-((tert-butyldimethylsilyloxy)methyl)piperidin-1-yl)benzoate (35.0 g, 96.26 mmol) in EtOH (150 mL) was added hydrazine (150 mL, 80%). The mixture was stirred at 90° C. for 6 hours and then concentrated in vacuo. The crude residue was diluted with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous NaSO, and filtered. The filtrate was concentrated in vacuo to give 4-(4-((tert-butyldimethylsilyloxy)methyl)piperidin-1-yl)benzohydrazide (29.0 g, crude) as a white solid, which was used in the next step without further purification. MS (ESI) calculated (C 19 H 33 N3O2Si)[M+H] + , 364.2; measured value 364.0.

[0215] Step 4: Synthesis of 2-(4-(4-((tert-butyldimethylsilyloxy)methyl)piperidin-1-yl)benzoyl)-N-methylhydrazinecarboxamide. To a solution of 4-(4-((tert-butyldimethylsilyloxy)methyl)piperidin-1-yl)benzohydrazide (29.0 g, 79.76 mmol) in MeCN (300 mL) was added 2,5-dioxopyrrolidin-1-yl N-methylcarbamate (20.6 g, 119.64 mmol) and DIEA (30.9 g, 239.28 mmol). The mixture was stirred at room temperature under a nitrogen atmosphere for 16 hours. The reaction mixture was quenched by adding water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous Na2SO4, and filtered. The filtrate was concentrated in vacuo to give 2-(4-(4-((tert-butyldimethylsilyloxy)methyl)piperidin-1-yl)benzoyl)-N-methylhydrazinecarboxamide (38.0 g, crude) as an off-white solid, which was used in the next step without further purification. MS (ESI) calculated (C 21 H 36 N4O3Si)[M+H] + , 421.3; measured value 421.0.

[0216] Step 5: Synthesis of 5-(4-(4-((tert-butyldimethylsilyloxy)methyl)piperidin-1-yl)phenyl)-4-methyl-2H-1,2,4-triazol-3(4H)-one. To a solution of NaOH (7.2 g, 180.68 mmol) in water (300 mL) was added 2-(4-(4-((tert-butyldimethylsilyloxy)methyl)piperidin-1-yl)benzoyl)-N-methylhydrazinecarboxamide (38.0 g, 90.34 mmol). The mixture was stirred at 100° C. under a nitrogen atmosphere for 3 hours. After cooling to room temperature, the resulting mixture was extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous NaSO, and concentrated in vacuo. The residue was purified by silica gel column chromatography using 0-10% methanol in dichloromethane to give 5-(4-(4-((tert-butyldimethylsilyloxy)methyl)piperidin-1-yl)phenyl)-4-methyl-2H-1,2,4-triazol-3(4H)-one (12 g, 33%) as an off-white solid. MS(ESI) calculated (C 21 H 34 NOSi)[M+H] + , 403.2; measured value 403.2.

[0217] Step 6: Synthesis of 3-(3-(4-(4-((tert-butyldimethylsilyloxy)methyl)piperidin-1-yl)phenyl)-4-methyl-5-oxo-4,5-dihydro-1,2,4-triazol-1-yl)piperidine-2,6-dione. To a solution of 5-(4-(4-((tert-butyldimethylsilyloxy)methyl)piperidin-1-yl)phenyl)-4-methyl-2H-1,2,4-triazol-3(4H)-one (9.6 g, 23.84 mmol) in DMF (100 mL) was added NaH (60%, 2.6 g, 65.0 mmol) in small portions at 0° C. The mixture was stirred at room temperature under a nitrogen atmosphere for 30 minutes. To the above mixture was added 3-bromopiperidine-2,6-dione (7.7 g, 40.10 mmol) at 0° C. The resulting mixture was stirred at 40°C for 4 hours under a nitrogen atmosphere. The reaction mixture was carefully poured into saturated aqueous NH4Cl and then extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, and filtered. The filtrate was concentrated in vacuo. The residue was purified by flash column chromatography using 0-8% methanol in dichloromethane to give 3-(3-(4-(4-((tert-butyldimethylsilyloxy)methyl)piperidin-1-yl)phenyl)-4-methyl-5-oxo-4,5-dihydro-1,2,4-triazol-1-yl)piperidine-2,6-dione (8.2 g, 66%) as a brown oil. MS(ESI) calculated (C 26 H 39 NOSi)[M+H] + , 514.3; measured value 514.3.

[0218] Step 7: Synthesis of 3-(3-(4-(4-(hydroxymethyl)piperidin-1-yl)phenyl)-4-methyl-5-oxo-4,5-dihydro-1,2,4-triazol-1-yl)piperidine-2,6-dione. A mixture of 3-(3-(4-(4-((tert-butyldimethylsilyloxy)methyl)piperidin-1-yl)phenyl)-4-methyl-5-oxo-4,5-dihydro-1,2,4-triazol-1-yl)piperidine-2,6-dione (350 mg, 0.68 mmol) in HCl (4 M in 1,4-dioxane, 5 mL) was stirred at room temperature for 2 hours. The solvent was removed in vacuo. The crude residue was diluted with DMF and basified to pH 8-9 using triethylamine. The resulting mixture was purified by reverse-phase flash chromatography using the following conditions: [column, C18 silica gel; mobile phase, ACN (0.05% NH4HCO3) in water, gradient from 10% to 35% in 30 min; detector, UV 254 nm] to give 3-(3-(4-(4-(hydroxymethyl)piperidin-1-yl)phenyl)-4-methyl-5-oxo-4,5-dihydro-1,2,4-triazol-1-yl)piperidine-2,6-dione (90 mg, 22%) as a white solid. 1 H NMR (300 MHz, DMSO-d6 + D2O) δ 7.55 - 7.41 (m, 2H), 7.12 - 6.88 (m, 2H), 5.15 - 5.05 (m, 1H), 3.85 - 3.76 (m, 2H), 3.34 - 3.20 (m, 5H), 2.91 - 2.58 (m, 4H), 2.48 - 2.34 (m, 1H), 2.21 - 2.05 (m, 1H), 1.78 - 1.66 (m, 2H), 1.63 - 1.48 (m, 1H), 1.24 - 1.08 (m, 2H).MS(ESI) calculated value(C 20 H 25 N5O4)[M+H] + , 400.2; measured value 400.1.

[0219] Step 8: rac-(R)-1-(4-(1-(2,6-dioxopiperidin-3-yl)-4-methyl-5-oxo-4,5-dihydro-1H-1,2,4-triazol-3-yl)phenyl)piperidine-4-carbaldehyde. To a solution of 3-(3-(4-(4-(hydroxymethyl)piperidin-1-yl)phenyl)-4-methyl-5-oxo-4,5-dihydro-1,2,4-triazol-1-yl)piperidine-2,6-dione (0.30 g, 0.75 mmol) in DCM (5 mL) was added Dess-Martin periodinane (0.38 g, 0.90 mmol). The reaction mixture was stirred at room temperature for 2 hours, filtered through a pad of Celite, concentrated onto silica gel, and then purified by column chromatography (0-100% EtOAc / hexanes) to provide the title compound. LCMS C 20 H 23 N5O4 Theoretical value: 397.2, Measured value: m / z = 398.4 [M+H] + Minute, 416.4[M+H2O] + Major. HCB12: 3-(2-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)amino)ethoxy)propanoic acid [ka]

[0220] Prepared in a similar manner to HCB1, substituting 2-(2,6-dioxopiperidin-3-yl)-4-fluoroisoindoline-1,3-dione with 2-(2,6-dioxopiperidin-3-yl)-5-fluoroisoindoline-1,3-dione to give the title compound. LCMS C 18 H 19 N3O7 theoretical value: 389.1, measured value: m / z = 387.8 [MH] - HCB13: 1-(1-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)piperidin-4-yl)azetidine-3-carboxylic acid [ka]

[0221] Step 1: Benzyl 4-{3-[(tert-butoxy)carbonyl]azetidin-1-yl}piperidine-1-carboxylate. To a solution of tert-butyl azetidine-3-carboxylate (4.5 g, 28.62 mmol, 1.0 equiv.) and 1-(benzyloxycarbonyl)-4-piperidinone (7.35 g, 31.49 mmol, 1.10 equiv.) in DCE (136 mL, 0.2 M) was added acetic acid (2.46 mL, 42.94 mmol, 1.5 equiv.), and the reaction was stirred at room temperature for 1 hour. Then, NaBH(OAc) (9.71 g, 45.8 mmol, 1.6 equiv.) was added, and the reaction was stirred at room temperature overnight. The reaction mixture was quenched with aqueous NaHCO, extracted with DCM (3x), washed with brine, dried over NaSO, and concentrated to dryness. The colorless oil was purified by flash column chromatography eluting with DCM:MeOH (0-10%) to give 9.39 g (88% yield) of the desired product as a white solid. ESI [M+H] + =375.6

[0222] Step 2: tert-Butyl 1-(piperidin-4-yl)azetidine-3-carboxylate. A solution of benzyl 4-{3-[(tert-butoxy)carbonyl]azetidin-1-yl}piperidine-1-carboxylate (9.39 g, 25.07 mmol, 1.0 equiv.) in MeOH (250 mL, 0.1 M) was degassed and backfilled with argon three times. Pd(OH) (0.7 g, 5.0 mmol, 0.2 equiv.) was then added, and the mixture was again degassed and backfilled with argon three times. The reaction mixture (RM) was then degassed, charged with a H balloon, and stirred overnight at room temperature. Cleavage of Cbz was confirmed by UPLC. The reaction mixture was filtered through a Celite pad, and the filtrate was concentrated to give 5.81 g (96% yield) of the desired product.

[0223] Step 3: tert-butyl 1-{1-[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl]piperidin-4-yl}azetidine-3-carboxylate. To a solution of 2-(2,6-dioxopiperidin-3-yl)-5-fluoro-2,3-dihydro-1H-isoindole-1,3-dione (6.05 g, 21.9 mmol, 1.0 equiv.) in DMSO (43.8 mL, 0.5 M) was added tert-butyl 1-(piperidin-4-yl)azetidine-3-carboxylate (5.79 g, 24.09 mmol, 1.1 equiv.) and DIPEA (7.63 mL, 43.8 mmol, 2.0 equiv.). The reaction mixture was then transferred to a preheated bath at 90°C and stirred overnight under an Ar atmosphere. UPLC showed the formation of the desired product. The reaction mixture (RM) was quenched with water, extracted with DCM (x3), and the organic phase was washed with ice-cold water. The crude material was purified by FC eluting with DCM:acetone (0-10%) to give 6.95 g (64% yield) of the product as a yellow solid. ESI [M+H] + =497.4.

[0224] Step 4: 1-{1-[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl]piperidin-4-yl}azetidine-3-carboxylate hydrochloride. To a solution of tert-butyl 1-{1-[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl]piperidin-4-yl}azetidine-3-carboxylate (4.95 g, 9.97 mmol, 1.0 equiv.) in anhydrous DCM (100 mL, 0.1 M) was added 2 M HCl in EtO (50 mL, 99.69 mmol, 10.0 equiv.). The reaction mixture was then stirred at room temperature for 2 hours, and UPLC showed that starting material (SM) remained. An additional portion of HCl in EtO (50 ml, 99.69 mmol, 10.0 equiv.) was added and the reaction mixture was stirred for an additional 3 h. UPLC indicated 10% starting material. The precipitate was filtered and redissolved in DCM, then 2 M HCl in EtO (50 ml, 99.69 mmol, 10.0 equiv.) was added and the reaction mixture was sonicated for 45 min. The precipitated solid was filtered off, washed with EtO, and dried under vacuum to give 4.83 g (quantitative yield) of the desired product as the HCl salt. LCMS (254 nm): RT = 2.83 min, 94.5%, ESI [M+H] + =441.07; 1 H NMR (300 MHz, D2O) δ 7.68 (d, J = 8.5 Hz, 1H), 7.37 (s, 1H), 7.22 (dd, J = 8.6, 2.3 Hz, 1H), 5.14 (dd, J = 12.8, 5.6 Hz, 1H), 4.49 - 4.28 (m, 4H), 4.08 (d, J = 13.6 Hz, 2H), 3.80 (t, J = 9.0 Hz, 1H), 3.69 - 3.56 (m, 1H), 3.03 (t, J = 12.8 Hz, 2H), 2.92 - 2.73 (m, 2H), 2.61 (qd, J = 12.8, 5.6 Hz, 1H), 2.24 - 2.09 (m, 2H), 1.59 - 1.42 (m, 2H). HCB14: 2-(4-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)piperazin-1-yl)acetic acid [ka]

[0225] Step 1: tert-Butyl 2-{4-[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl]piperazin-1-yl}acetate. To a solution of tert-butyl piperazin-1-yl acetate dihydrochloride (4.46 g, 0.0163 mmol, 1.1 equiv.) in DMSO (29.7 mL, 0.5 M) was added DIPEA (3.93 mL, 0.0297 mmol, 2 equiv.) and 2-(2,6-dioxopiperidin-3-yl)-5-fluoroisoindoline-1,3-dione (4.1 g, 0.0148 mmol, 1 equiv.). The reaction mixture was heated at 90° C. for 40 hours under argon. The reaction mixture was cooled to room temperature, and 5 mL of water was added dropwise. A bright yellow precipitate formed, which was filtered off and washed twice on the filter with water. The filtrate was extracted twice with DCM. The combined DCM layers were concentrated in vacuo and combined with the precipitate. The crude was purified by flash column chromatography to give tert-butyl 2-{4-[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl]piperazin-1-yl}acetate (5.49 g, 81% yield) as a yellow solid. ESI [M+H] + =457.7; 1H NMR (300 MHz, Chloroform-d) δ 8.07 (s, 1H), 7.72 (d, J = 8.5 Hz, 1H), 7.31 (d, J = 2.3 Hz, 1H), 7.08 (dd, J = 8.6, 2.4 Hz, 1H), 4.96 (dd, J = 12.2, 5.2 Hz, 1H), 3.55 - 3.45 (m, 4H), 3.21 (s, 2H), 2.98 - 2.81 (m, 2H), 2.81 - 2.72 (m, 5H), 2.24 - 2.09 (m, 1H), 1.50 (s, 9H).

[0226] Step 2: Trifluoroacetate salt of 2-{4-[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl]piperazin-1-yl}acetic acid. To a solution of tert-butyl 2-{4-[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxo-2,3-dihydro-1H-isoindol-5-yl]piperazin-1-yl}acetate (5.49 g, 12.03 mmol, 1 equiv.) in DCM (100 mL, 0.12 M) was added TFA (50.6 mL, 661 mmol, 55 equiv.). The reaction mixture was stirred at room temperature for 16 hours and then concentrated under reduced pressure. The resulting light yellow sticky solid was sonicated with 200 mL of anhydrous diethyl ether and further stirred for 1 hour. The resulting precipitate was filtered, washed twice with anhydrous EtO, and dried under reduced pressure to give a light yellow solid (6.55 g, quantitative). LCMS (254 nm): RT=2.69 min, 98.59%, ESI [M+H] + =401.14; 1H NMR (400 MHz, DMSO-d6) δ 11.11 (s, 1H), 10.87 (br. s, 1H), 7.77 (d, J = 8.4 Hz, 1H), 7.48 (d, J = 2.3 Hz, 1H), 7.34 (dd, J = 8.6, 2.3 Hz, 1H), 6.27 (br. s, 2H), 5.10 (dd, J = 12.9, 5.4 Hz, 1H), 4.22 (s, 2H), 4.11 (br. s, 2H), 3.45 (br. s, 6H), 3.38 (dd, J = 139.7, 7.0 Hz, 8H), 2.90 (ddd, J = 17.4, 14.1, 5.5 Hz, 1H), 2.65 - 2.52 (m, 2H), 2.10 - 1.97 (m, 1H). HCB15: 6-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)hexanoic acid [ka]

[0227] Prepared in a similar manner to HCB3, substituting 2-(2,6-dioxopiperidin-3-yl)-5-fluoroisoindoline-1,3-dione with 2-(2,6-dioxopiperidin-3-yl)-4-fluoroisoindoline-1,3-dione to give the title compound. LCMS C 19 H 21 N3O6 theoretical value: 387.1, measured value: m / z = 385.9 [MH] - HCB16: 8-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)amino)octanoic acid [ka]

[0228] Prepared in a similar manner to HCB3, substituting tert-butyl 6-aminohexanoate hydrochloride for tert-butyl 8-aminooctanoate to give the title compound. LCMS C 21 H 25 N3O6 theoretical value: 415.2, measured value: m / z = 414.2 [MH] - HCB17: 2-(4-(2-(1-methyl-2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)piperazin-1-yl)acetic acid [ka]

[0229] The title compound was synthesized in a manner similar to HCB14, replacing 2-(2,6-dioxopiperidin-3-yl)-5-fluoroisoindoline-1,3-dione with 5-fluoro-2-(1-methyl-2,6-dioxopiperidin-3-yl)isoindoline-1,3-dione. LCMS C 20 H 22 N4O6 theoretical value: 414.2, measured value: m / z = 415.4 [M+H] + HCB18: N-(2,6-dioxopiperidin-3-yl)-5-(4-formylpiperidin-1-yl)pyridine-2-carboxamide [ka]

[0230] Step 1: Methyl 5-{4-[(benzyloxy)methyl]piperidin-1-yl}pyridine-2-carboxylate. Methyl 5-bromopyridine-2-carboxylate (1.0 g, 4.63 mmol, 1.0 equiv), 4-[(benzyloxy)methyl]piperidine (950 mg, 4.63 mmol, 1.0 equiv), rac-BINAP (288 mg, 463 μmol, 0.1 equiv), Pd(dba) (432 mg, 463 μmol, 0.1 equiv), and CsCO (4.52 g, 13.9 mmol, 3.0 equiv) were suspended in toluene (30 mL), and the mixture was heated to 100° C. for 12 h. The reaction mixture was cooled to room temperature, diluted with EtOAc (100 mL), filtered and purified (SiO2, eluting with 10→100% EtOAc / hexanes, 70%) to give methyl 5-{4-[(benzyloxy)methyl]piperidin-1-yl}pyridine-2-carboxylate (1.1 g, 67%). LCMS: C 20 H 24 N2O3 theoretical value: 340, measured value: m / z = 341 [M+H] + .

[0231] Step 2: 5-{4-[(benzyloxy)methyl]piperidin-1-yl}pyridine-2-carboxylic acid. Methyl 5-{4-[(benzyloxy)methyl]piperidin-1-yl}pyridine-2-carboxylate (510 mg, 1.50 mmol, 1.0 equiv) was suspended in MeOH / HO (1:4) and NaOH (90 mg, 2.25 mmol, 1.5 equiv) was added in one portion at room temperature. After 16 h, HCl (1 M, aq.) was added to bring the solution to pH=5. The solid was collected by filtration to give 5-{4-[(benzyloxy)methyl]piperidin-1-yl}pyridine-2-carboxylic acid (800 mg, 83%). LCMS: C 19 H 22 N2O3 theoretical value: 326, measured value: m / z = 327 [M+H] + .

[0232] Step 3: 5-{4-[(benzyloxy)methyl]piperidin-1-yl}-N-(2,6-dioxopiperidin-3-yl)pyridine-2-carboxamide. 5-{4-[(benzyloxy)methyl]piperidin-1-yl}pyridine-2-carboxylic acid (510 mg, 1.56 mmol, 1.0 equiv.) was dissolved in DMF (1 mL) and HATU (594 mg, 1.56 mmol, 1.0 equiv.) was added at room temperature. After 5 minutes, 3-aminopiperidine-2,6-dione hydrochloride (257 mg, 1.56 mmol, 1.0 equiv.) and DIPEA (1.09 mL, 6.25 mmol, 4.0 equiv.) were added. The mixture was stirred for 16 hours and partitioned between EtOAc and HO (20 mL each). The organic phase was washed (2 x 5 mL H2O, 1 x 5 mL brine), dried (Na2SO4), filtered, and concentrated. Purification (SiO2, 0->4% MeOH / CH2Cl2) afforded 5-{4-[(benzyloxy)methyl]piperidin-1-yl}-N-(2,6-dioxopiperidin-3-yl)pyridine-2-carboxamide (625 mg, 92%) as a white solid. LCMS: C 24 H 28 N4O4 theoretical value: 436, measured value: m / z = 437 [M+H] + .

[0233] Step 4: N-(2,6-Dioxopiperidin-3-yl)-5-[4-(hydroxymethyl)piperidin-1-yl]pyridine-2-carboxamide. Under a H atmosphere (balloon), 5-{4-[(benzyloxy)methyl]piperidin-1-yl}-N-(2,6-dioxopiperidin-3-yl)pyridine-2-carboxamide (500 mg, 1.15 mmol, 1.0 equiv.), acetic acid (196 μL, 3.44 mmol, 3.0 equiv.), Pd(OH) (50 mg), and Pd / C (50 mg) were suspended in EtOH (100 mL). The mixture was heated to 40° C. for 18 h, then cooled, filtered, and concentrated. Purification (SiO 2 , 0→8% MeOH / CH 2 Cl 2 ) afforded N-(2,6-dioxopiperidin-3-yl)-5-[4-(hydroxymethyl)piperidin-1-yl]pyridine-2-carboxamide (233 mg, 58%) as a white solid. 1H NMR (500 MHz, DMSO-d6) δ 10.84 (s, 1H), 8.69 (d, J = 8.3 Hz, 1H), 8.30 (d, J = 3.0 Hz, 1H), 7.83 (d, J = 8.8 Hz, 1H), 7.40 (dd, J = 9.0, 3.0 Hz, 1H), 4.74 (dq, J = 13.3, 6.4, 5.8 Hz, 1H), 3.95 (d, J = 12.7 Hz, 2H), 3.28 (d, J = 6.1 Hz, 2H), 2.88 - 2.73 (m, 3H), 2.53 (s, 2H), 2.23 - 2.11 (m, 1H), 2.01 (d, J = 13.1 Hz, 1H), 1.78 - 1.71 (m, 2H), 1.61 (s, 1H), 1.21 (h, J = 11.0, 10.6 Hz, 2H).LCMS:C 17 H 22 N4O4 theoretical value: 346, measured value: m / z = 347 [M+H] + .

[0234] Step 5: N-(2,6-dioxopiperidin-3-yl)-5-(4-formylpiperidin-1-yl)pyridine-2-carboxamide. A mixture of N-(2,6-dioxopiperidin-3-yl)-5-[4-(hydroxymethyl)piperidin-1-yl]pyridine-2-carboxamide (200 mg, 580 μmol, 1.0 equiv.) and EtN (321 μL, 2.31 mmol, 4.0 equiv.) was dissolved in DMSO (500 μL) and CHCl (500 μL). The reaction mixture was cooled to 0° C. and the resulting mixture was stirred for 1 hour at RT. 3·Pyridine (184 mg, 1.15 equiv., 2.0 equiv., solution in 300 μL DMSO) was added dropwise. The reaction mixture was warmed to room temperature and stirred for 30 min, after which NaHCO (5 mL, saturated aqueous solution) was added. After 1 min, the suspension was diluted with CHCl (10 mL) and the aqueous phase was extracted (3×10 mL CHCl). The combined organics were washed (2×5 mL H0, 1×5 mL brine), dried (NaSO), filtered, and concentrated. Purification (SiO, eluting with 0→10% MeOH / CHCl, 5%) afforded N-(2,6-dioxopiperidin-3-yl)-5-(4-formylpiperidin-1-yl)pyridine-2-carboxamide as a white foam (190 mg, 95%). LCMS: C 17 H 20 N4O4 theoretical value: 344, measured value: m / z = 345 [M+H] + . HCB19: N-(2,6-dioxopiperidin-3-yl)-4-formylbenzamide [ka]

[0235] 4-Formylbenzoic acid (500 mg, 3.33 mmol) and HATU were combined in DMF, then DIPEA (4 eq, 13.3 mmol) was added and stirred for 5 min. 3-Aminopiperidine-2,6-dione hydrochloride was then added and the reaction was stirred for 18 h before being purified directly by reverse phase chromatography (C18 column, 0-100% acetonitrile in water) to give the desired product (0.6 g, 69% yield).

[0236] LCMS:C 13 H 12 N2O4 theoretical value: 260.1, measured value: m / z = 261.2 [M+H] + . HCB20: (3R)-1-(1-(2,6-dioxopiperidin-3-yl)-3-methyl-2-oxo-2,3-dihydro-1H-benzo[d]imidazol-5-yl)pyrrolidine-3-carbaldehyde [ka]

[0237] Step 1: tert-Butyl (3R)-3-[[tert-butyl(diphenyl)silyl]oxymethyl]pyrrolidine-1-carboxylate. To a mixture of tert-butyl (3R)-3-(hydroxymethyl)pyrrolidine-1-carboxylate (25.0 g, 124 mmol) and imidazole (10.1 g, 149 mmol) in DCM (500 mL) was added TBDPSCl (32.3 mL, 124 mmol) at 0° C. under nitrogen. The mixture was stirred at 23° C. for 16 hours and diluted with water (300 mL). The organic phase was washed with water (100 mL), brine (3×100 mL), dried (NaSO), filtered, and concentrated to give the title compound as an oil (54.0 g, 99%). m / z: ES + [M-C6H5-tBu+H] + =306.2, LCMS(A05);t R =2.47 minutes. ; 1 H NMR (500 MHz, CDCl3) δ 7.67 - 7.60 (m, 4H), 7.46 - 7.34 (m, 6H), 3.64 - 3.55 (m, 2H), 3.45 - 3.37 (m, 1H), 3.37 - 3.22 (m, 1H), 3.17 - 3.07 (m, 1H), 2.42 (m, 1H), 1.97 - 1.86 (m, 1H), 1.74 - 1.62 (m, 1H), 1.60 (s, 1H), 1.46 (s, 9H), 1.08 - 1.02 (m, 9H);

[0238] Step 2: tert-Butyl-diphenyl-[[(3R)-pyrrolidin-3-yl]methoxy]silane 2,2,2-trifluoroacetic acid. To a mixture of tert-butyl (3R)-3-[[tert-butyl(diphenyl)silyl]oxymethyl]pyrrolidine-1-carboxylate (54.0 g, 123 mmol) in DCM (200 mL) was added TFA (50 mL) at 23° C. under nitrogen. The mixture was stirred at 23° C. for 1.5 hours and concentrated. The residue was diluted with PhMe (150 mL) and concentrated (this process was repeated twice) to give the title compound as an oil (55.7 g, quantitative). m / z: ES + [M+H-TFA] + =340.3, LCMS(A05);t R =2.32 minutes. 1 H NMR (500 MHz, CDCl3) δ 8.82 (s, 2H), 7.65 - 7.57 (m, 4H), 7.52 - 7.40 (m, 6H), 3.65 (d, J = 6.4 Hz, 2H), 3.35 - 3.27 (m, 1H), 3.24 - 3.10 (m, 2H), 3.01 - 2.91 (m, 1H), 2.58 - 2.52 (m, 1H), 2.04 - 1.93 (m, 1H), 1.74 - 1.63 (m, 1H), 1.01 (s, 9H);

[0239] Step 3: Dimethyl 2-bromopentanedioate. To a mixture of (2S)-2-aminopentanedioic acid (30 g, 204 mmol), NaBr (73.2 g, 711 mol), and HBr (50 mL, 48% in water) in water (100 mL) was added a solution of NaNO (25.5 g, 370 mmol) in water (50 mL) under nitrogen at 0 °C (internal temperature maintained below 10 °C). The mixture was stirred at 23 °C for 6 h, and HSO (25.0 mL) was added at 23 °C. The mixture was extracted with EtO (4 × 70.0 mL), and the combined organic phases were washed with brine (2 × 50.0 mL), dried (NaSO), filtered, and concentrated. To a mixture of the residue in MeOH (80.0 mL) under nitrogen at 23 °C, HSO (10.0 mL) was added. The mixture was refluxed for 16 hours, cooled to 23°C, and concentrated. The residue was diluted with EtO (100 mL) and water (100 mL). The aqueous phase was extracted with EtO (4 x 50.0 mL). The combined organic layers were washed with water (60.0 mL), NaHCO (2 x 60.0 mL), brine (2 x 50.0 mL), dried (NaSO), filtered, and concentrated to give the title compound as an oil (19 g, 39%). 1 H NMR (400 MHz, CDCl3) δ 4.34 (dd, J = 8.5, 5.8 Hz, 1H), 3.75 (s, 3H), 3.65 (s, 3H), 2.52 - 2.45 (m, 2H), 2.40 - 2.30 (m, 1H), 2.26 (m, 1H).

[0240] Step 4: 5-Bromo-N-methyl-2-nitro-aniline. To a mixture of 4-bromo-2-fluoro-1-nitro-benzene (50.0 g, 227 mmol) in EtOH (455 mL) was added methylamine (56.6 mL, 455 mmol, 33 wt % in EtOH) at 23° C. under nitrogen. The mixture was stirred at 23° C. for 30 minutes, filtered, and washed with cold EtOH (200 mL) to give the title compound as a solid (48.2 g, 92%). m / z (ES + ) [M+H] + =231.0, LCMS(A05);t R =2.51 minutes;.1 H NMR (400 MHz, DMSO-d6) δ 8.23 ​​(d, J = 4.3 Hz, 1H), 7.98 (d, J = 9.1 Hz, 1H), 7.17 (d, J = 2.0 Hz, 1H), 6.82 (dd, J = 9.1, 2.1 Hz, 1H), 2.95 (d, J = 5.0 Hz, 3H)

[0241] Step 5: [(3R)-1-[3-(methylamino)-4-nitrophenyl]pyrrolidin-3-yl]methanol. To a mixture of 5-bromo-N-methyl-2-nitroaniline (25 g, 108 mmol), tert-butyl-diphenyl-[[(3R)-pyrrolidin-3-yl]methoxy]silane 2,2,2-trifluoroacetic acid (60.0 g, 119 mmol, 90% purity), and CsCO (106 g, 325 mmol) in PhMe (600 mL) was added RuPhos-Pd-G (2.71 g, 3.25 mmol) under nitrogen at 23 °C. The mixture was degassed by bubbling nitrogen through at 23 °C for 15 minutes, stirred at 100 °C for 19 hours, cooled to 23 °C, filtered, and concentrated. The product was purified by silica gel chromatography (2 x 330 g cartridges in series) using hexanes and EtOAc (0-50%) to give the title compound as a solid (41.0 g, 77%). m / z: ES + [M+H] + =490.4; 1H NMR (400 MHz, DMSO-d6) δ 8.36 (d, J = 4.9 Hz, 1H), 7.91 (d, J = 9.6 Hz, 1H), 7.64 - 7.57 (m, 4H), 7.50 - 7.37 (m, 6H), 6.07 (dd, J = 9.6, 2.5 Hz, 1H), 5.50 (d, J = 2.4 Hz, 1H), 3.68 (d, J = 6.6 Hz, 2H), 3.54 - 3.46 (m, 1H), 3.46 - 3.37 (m, 2H), 3.27 - 3.21 (m, 1H), 2.90 (d, J = 5.0 Hz, 3H), 2.64 - 2.55 (m, 1H), 2.16 - 2.04 (m, 1H), 1.90 - 1.79 (m, 1H), 1.01 (s, 9H)

[0242] Step 6: 4-[(3R)-3-Ethylpyrrolidin-1-yl]-N2-methyl-benzene-1,2-diamine. A solution of [(3R)-1-[3-(methylamino)-4-nitro-phenyl]pyrrolidin-3-yl]methanol (20.0 g, 40.8 mmol) in THF (100 mL) and EtOH (100 mL) was added to 10% Pd / C (4.4 g, 4.1 mmol, 50% wet) at 23 °C under nitrogen. The mixture was refluxed, and hydrazine hydrate (16 mL, 163 mmol) was added (over 30 minutes). The mixture was refluxed for 2 hours, cooled to 23 °C, filtered (Celite), washed with EtOAc (200 mL) and EtOH (200 mL), and concentrated to give the title compound as an oil (18.0 g, 96%). m / z ESI + [M-Ph-tBu+H] + =328.16; 1H NMR (400 MHz, DMSO-d6) δ 7.65 - 7.59 (m, 4H), 7.48 - 7.38 (m, 6H), 6.45 - 6.40 (m, 1H), 5.71 (d, J = 2.5 Hz, 1H), 5.66 (dd, J = 8.1, 2.5 Hz, 1H), 4.50 (d, J = 4.9 Hz, 1H), 3.65 (d, J = 6.8 Hz, 2H), 3.33 (br. s, 2H), 3.21 (dd, J = 9.1, 7.6 Hz, 1H), 3.14 - 3.07 (m, 2H), 2.97 (dd, J = 9.2, 5.9 Hz, 1H), 2.68 (d, J = 4.2 Hz, 3H), 2.56 - 2.51 (m, 1H), 2.05 - 1.95 (m, 1H), 1.76 - 1.67 (m, 1H), 1.01 (s, 9H);

[0243] Step 7: 5-[(3R)-3-Ethylpyrrolidin-1-yl]-3-methyl-1H-benzimidazol-2-one. To a mixture of ISN-4-[(3R)-3-ethylpyrrolidin-1-yl]-N2-methyl-benzene-1,2-diamine (38.0 g, 82.7 mmol) and DIPEA (115 mL, 661 mmol) in DCM (300 mL) was added a mixture of triphosgene (8.09 g, 27.3 mmol) in DCM (30 mL) at 0 °C under nitrogen. The mixture was stirred at 0 °C for 30 minutes and diluted with water (300 mL). The aqueous phase was extracted with DCM (2 × 100 mL), and the combined organic phase was washed with brine (50.0 mL), dried (MgSO), filtered, and concentrated. The product was purified by silica gel chromatography (2 x 330 g cartridges) using DCM and MeOH (0-10%) to give the title compound as a solid (21 g, 52%). m / z: ES + [M+H] + =486.4.

[0244] Step 8: Dimethyl 2-[5-[(3R)-3-ethylpyrrolidin-1-yl]-3-methyl-2-oxo-benzimidazol-1-yl]pentanedioate. To a mixture of 5-[(3R)-3-ethylpyrrolidin-1-yl]-3-methyl-1H-benzimidazol-2-one (10.0 g, 20.6 mmol) and CsCO (20.3 g, 62.3 mmol) in DMF (100 mL) was added dimethyl 2-bromopentanedioate (10.9 g, 30.9 mmol, 68% purity) at 23 °C under nitrogen. The mixture was stirred at 100 °C for 18 hours, cooled to 23 °C, and diluted with EtOAc (200 mL) and water (100 mL). The aqueous phase was extracted with EtOAc (2 x 100 mL), and the combined organic phases were washed with brine (2 x 50 mL), dried (MgSO), filtered, and concentrated. The product was purified by silica gel chromatography (220 g cartridge) using hexanes and EtOAc (0-50%) to give the title compound as a solid (9.00 g, 68%). m / z: ES + [M+H] + =644.4, LCMS(A05);t R =2.33 minutes.

[0245] Step 9: 2-[5-[(3R)-3-Ethylpyrrolidin-1-yl]-3-methyl-2-oxo-benzimidazol-1-yl]pentanedioic acid. To a mixture of dimethyl 2-[5-[(3R)-3-ethylpyrrolidin-1-yl]-3-methyl-2-oxo-benzimidazol-1-yl]pentanedioate (9.00 g, 14.0 mmol) in a mixture of THF and water (200 mL, 1:1 v / v) was added aqueous NaOH (5 M, 14.0 mL, 70.0 mmol) under nitrogen at 23 °C. The mixture was stirred at 23 °C for 1 hour and diluted with EtOAc (100 mL) and aqueous HCl (1 M, 80.0 mL). The aqueous phase was extracted with EtOAc (3×50.0 mL) and the combined organic phases were washed with brine (2×50.0 mL), dried (Na 2 SO 4 ), filtered and concentrated to give the title compound as a solid (8.6 g, quantitative). 1H NMR (500 MHz, DMSO-d6) δ 7.67 - 7.58 (m, 4H), 7.51 - 7.36 (m, 6H), 6.93 - 6.81 (m, 1H), 6.41 - 6.30 (m, 1H), 6.27 - 6.17 (m, 1H), 4.95 (dd, J = 10.8, 5.0 Hz, 1H), 3.69 (d, J = 6.6 Hz, 2H), 3.38 - 3.31 (m, 1H), 3.29 (s, 3H), 3.27 - 3.19 (m, 2H), 3.12 - 3.03 (m, 1H), 2.65 - 2.55 (m, 1H), 2.41 - 2.21 (m, 2H), 2.21 - 2.02 (m, 3H), 1.86 - 1.79 (m, 1H), 1.02 (s, 9H).

[0246] Step 10: 3-[5-[(3R)-3-Ethylpyrrolidin-1-yl]-3-methyl-2-oxo-benzimidazol-1-yl]piperidine-2,6-dione. To a mixture of 2-[5-[(3R)-3-ethylpyrrolidin-1-yl]-3-methyl-2-oxo-benzimidazol-1-yl]pentanedioic acid (5.0 g, 8.12 mmol), trifluoroacetamide (1.01 g, 8.93 mmol), and DIPEA (5.66 mL, 32.5 mmol) in DMF (50.0 mL) was added HATU (6.792 g, 17.9 mmol) under nitrogen at 23 ° C. The mixture was stirred at 23 ° C. for 18 hours and concentrated. The product was purified by silica gel chromatography (120 g cartridge) using DCM and MeOH (0-5%) to give the title compound as a solid (3.30 g, 68%). 1H NMR (500 MHz, DMSO-d6) δ 11.04 (s, 1H), 7.65 - 7.60 (m, 4H), 7.50 - 7.39 (m, 6H), 6.93 - 6.87 (m, 1H), 6.35 (d, J = 2.1 Hz, 1H), 6.20 (dd, J = 8.6, 2.2 Hz, 1H), 5.26 (dd, J = 12.8, 5.4 Hz, 1H), 3.69 (d, J = 6.6 Hz, 2H), 3.29 (s, 3H), 3.26 - 3.20 (m, 2H), 3.08 - 3.02 (m, 1H), 2.93 - 2.85 (m, 1H), 2.70 (s, 2H), 2.67 - 2.55 (m, 2H), 2.13 - 2.04 (m, 1H), 1.98 - 1.95 (m, 1H), 1.86 - 1.76 (m, 1H), 1.02 (s, 9H).

[0247] Step 11: 3-[5-[(3R)-3-(hydroxymethyl)pyrrolidin-1-yl]-3-methyl-2-oxo-benzimidazol-1-yl]piperidine-2,6-dione. To a mixture of 3-[5-[(3R)-3-ethylpyrrolidin-1-yl]-3-methyl-2-oxo-benzimidazol-1-yl]piperidine-2,6-dione (3.20 g, 5.36 mmol) in THF (20 mL) was added TBAF (8.00 mL, 8.00 mmol, 1 M in THF) at 23 °C under nitrogen. The mixture was stirred at 23 °C for 3 hours and concentrated. The product was purified by silica gel chromatography (220 g cartridge) using DCM and MeOH (0-12%) to give the title compound as a solid (1.30 g, 67%). m / z: ES + [M] + =358.2; 1H NMR (400 MHz, DMSO-d6) δ 11.03 (s, 1H), 6.89 (d, J = 8.5 Hz, 1H), 6.37 (d, J = 2.2 Hz, 1H), 6.21 (dd, J = 8.6, 2.2 Hz, 1H), 5.25 (dd, J = 12.9, 5.4 Hz, 1H), 4.69 (t, J = 5.2 Hz, 1H), 3.48 - 3.36 (m, 2H), 3.37 - 3.32 (m, 1H), 3.29 (s, 3H), 3.27 - 3.15 (m, 2H), 3.05 - 2.97 (m, 1H), 2.95 - 2.83 (m, 1H), 2.73 - 2.55 (m, 2H), 2.48 - 2.37 (m, 1H), 2.08 - 1.92 (m, 2H), 1.79 - 1.68 (m, 1H);

[0248] Step 12: (3R)-1-(1-(2,6-Dioxopiperidin-3-yl)-3-methyl-2-oxo-2,3-dihydro-1H-benzo[d]imidazol-5-yl)pyrrolidine-3-carbaldehyde. To a mixture of (3RS)-3-{5-[(3R)-3-(hydroxymethyl)pyrrolidin-1-yl]-3-methyl-2-oxo-1,3-benzodiazol-1-yl}piperidine-2,6-dione (33.50 mg, 0.09 mmol) in DMSO (1.00 mL) was added triethylamine (0.26 mL, 0.19 g, 1.87 mmol), followed by sulfur trioxide pyridine complex (148.77 mg, 0.93 mmol). After 25 minutes, water was added, and the mixture was extracted twice with DCM. The combined organic layers were concentrated to give the title compound without further purification. m / z: ES + [M] +=357.2. VHL-targeting LHM building blocks can generally be prepared according to Scheme B3, in which the LHM is first linked to a linker precursor comprising "Linker A" (representing one or more linker segments) and two reactive terminal groups. One of the reactive groups is a carboxylic acid or its reactive equivalent; the other reactive group, X, can be, for example, a carboxylic acid, hydroxyl, or aldehyde group. The resulting LHM building block has a reactive moiety (X), which can be further linked to another moiety. HCB21: N-(2,6-dioxopiperidin-3-yl)-4-(4-formylpiperidin-1-yl)-N-methylbenzamide [ka]

[0249] Step 1: 3-[benzyl(methyl)amino]piperidine-2,6-dione. A mixture of 3-bromopiperidine-2,6-dione (6.00 g, 31.2 mmol), N-methyl-1-phenyl-methanamine (10.0 g, 82.5 mmol) in DMF (30.0 mL) was stirred at 23 °C for 16 hours. The mixture was concentrated. The residue was diluted with toluene (100 mL) and DCM (20.0 mL). The solid was filtered off. The filtrate was further diluted with water (200 mL), ether (100 mL), and EtOAc (200 mL). The organic phase was separated, and the aqueous phase was extracted with EtOAc (3 × 100 mL). The combined organic phase was washed with brine (3 × 50.0 mL), dried (NaSO), filtered, and concentrated. The residue was suspended in hexane / ether (10:1 by volume; 200 mL) and stirred for 10 minutes. The solid was collected by filtration and dried under high vacuum to give the title compound (5.65 g, 78%) as an off-white solid. 1H NMR (500 MHz, DMSO-d6) δ 10.63 (s, 1H), 7.36 - 7.29 (m, 4H), 7.27 - 7.21 (m, 1H), 3.78 (s, 2H), 3.61 (dd, J = 12.1, 4.7 Hz, 1H), 2.66 - 2.57 (m, 1H), 2.51 (s, 1H), 2.25 (s, 3H), 2.15 - 2.05 (m, 1H), 1.98 - 1.90 (m, 1H).

[0250] Step 2: 3-(Methylamino)piperidine-2,6-dione. To 10% Pd / C (1.58 g, 1.49 mmol) in a Parr shaker vessel under nitrogen was added a solution of 3-[benzyl(methyl)amino]piperidine-2,6-dione (5.65 g, 24.3 mmol) in EtOAc (60.0 mL). The mixture was purged with hydrogen and stirred at 50 psi and 23° C. for 18 hours. The mixture was filtered through Celite and washed with EtOAc (100 mL) and DCM (100 mL). The filtrate was concentrated to give the title compound as a light blue solid (3.10 g, 90%). 1 H NMR (400 MHz, DMSO-d6) δ 10.63 (s, 1H), 3.16 (dd, J = 10.3, 4.8 Hz, 1H), 2.52 - 2.41 (m, 2H), 2.27 (s, 3H), 2.26 - 2.22 (m, 1H), 2.02 - 1.93 (m, 1H), 1.71 - 1.57 (m, 1H).m / z(ES + ), [M+H] + 143.1

[0251] Step 3: Benzyl 4-(1,3-dioxolan-2-yl)piperidine-1-carboxylate. A solution of benzyl 4-formylpiperidine-1-carboxylate (25.0 g, 101 mmol), PTSA (515 mg, 2.71 mmol), and ethylene glycol (35.0 mL, 142 mmol) in toluene (120 mL) was refluxed for 7 hours using a Dean-Stark apparatus. After cooling to 23 °C, the mixture was concentrated. The residue was diluted with saturated NaHCO (100 mL) and EtOAc (200 mL). The organic phase was separated, washed with saturated NaHCO (2 × 50.0 mL), brine (2 × 100 mL), dried (NaSO), filtered, and concentrated to give the title compound as a pale yellow oil (29.5 g, 100%). 1 H NMR (400 MHz, CDCl3) δ 7.36 - 7.24 (m, 5H), 5.09 (s, 2H), 4.61 (d, J = 4.6 Hz, 1H), 4.30 - 4.08 (m, 2H), 3.94 - 3.86 (m, 2H), 3.86 - 3.78 (m, 2H), 2.83 - 2.63 (m, 2H), 1.77 - 1.64 (m, 3H), 1.40 - 1.21 (m, 2H).

[0252] Step 4: 4-(1,3-Dioxolan-2-yl)piperidine. To 10% Pd / C (7.20 g, 6.76 mmol) under nitrogen was added a solution of benzyl 4-(1,3-dioxolan-2-yl)piperidine-1-carboxylate (29.5 g, 422 mmol) in EtOH (120 mL). The suspension was purged with hydrogen and stirred at 23 °C for 4 h. The mixture was filtered through Celite and washed with DCM (200 mL). The filtrate was concentrated to give the title compound (15.1 g, 95%) as a colorless oil. 1H NMR (500 MHz, CDCl3) δ 4.60 (dd, J = 5.1, 2.3 Hz, 1H), 3.96 - 3.89 (m, 2H), 3.84 (dd, J = 4.2, 2.2 Hz, 2H), 3.08 (d, J = 2.0 Hz, 2H), 2.58 (tt, J = 12.3, 2.3 Hz, 2H), 1.70 (s, 2H), 1.68 - 1.61 (m, 1H), 1.34 - 1.24 (m, 2H), 1.21 (d, J = 3.3 Hz, 1H).

[0253] Step 5: Methyl 4-[4-(1,3-dioxolan-2-yl)-1-piperidyl]benzoate. A mixture of 4-(1,3-dioxolan-2-yl)piperidine (8.00 g, 50.9 mmol), methyl 5-fluoropyridine-2-carboxylate (7.85 g, 50.9 mmol), and K2CO3 (7.04 g, 50.9 mmol) in anhydrous DMSO (20.0 mL) was heated at 80 °C for 4 hours. After cooling to 23 °C, water (200 mL) was added. The solid was collected by filtration and dried under high vacuum to give the title compound as an off-white solid (13.8 g, 93%). m / z (ES + ), [M+H] + 292.2

[0254] Step 6: 4-[4-(1,3-dioxolan-2-yl)-1-piperidyl]benzoic acid. To a mixture of methyl 4-[4-(1,3-dioxolan-2-yl)-1-piperidyl]benzoate (10.0 g, 34.3 mmol) in a water / THF mixture (1:1 v / v, 200 mL) was added aqueous NaOH (5 M, 35.0 mL, 175 mmol). The solution was stirred at 23 °C for 2 h. The reaction mixture was diluted with EtOAc (100 mL) and the pH was adjusted to 4 by adding aqueous HCl (1 M). The organic phase was separated, and the aqueous phase was extracted with EtOAc (4 × 100 mL). The combined organic phases were washed with brine (100 mL), dried (NaSO), filtered, and concentrated to give the title compound as a light brown solid (7.10 g, 75%). m / z (ES +), [M+H] + 278.2

[0255] Step 7: 4-[4-(1,3-Dioxolan-2-yl)-1-piperidyl]-N-(2,6-dioxo-3-piperidyl)-N-methyl-benzamide. To a mixture of 4-[4-(1,3-dioxolan-2-yl)-1-piperidyl]benzoic acid (2.50 g, 9.01 mmol), HATU (6.86 g, 18.0 mmol), and 3-(methylamino)piperidine-2,6-dione (1.54 g, 10.8 mmol) in anhydrous DMF (20.0 mL) was added DIPEA (3.58 mL, 20.6 mmol) at 23 °C. The mixture was stirred at 23 °C for 2 hours and diluted with water (200 mL). The aqueous phase was extracted with a mixture of iPrOH / CHCl (1 / 9 v / v, 4 × 100 mL). The combined organic phase was washed with brine (100 mL), dried (NaSO), filtered, and concentrated. The residue was suspended in EtO (200 mL) and sonicated for 5 min. The solid was collected by filtration and dried under high vacuum to give the title compound as a colorless solid (1.70 g, 45%). m / z (ES + ), [M+H] + 402.3

[0256] Step 8: N-(2,6-Dioxo-3-piperidyl)-4-(4-formyl-1-piperidyl)-N-methyl-benzamide. To a mixture of 4-[4-(1,3-dioxolan-2-yl)-1-piperidyl]-N-(2,6-dioxo-3-piperidyl)-N-methyl-benzamide (1.60 g, 3.99 mmol) in THF (16.0 mL) and water (60.0 mL) was added aqueous HCl (3 M, 10.0 mL, 30 mmol) at 23 °C. The solution was heated at 55 °C for 5 h. After cooling to 0 °C, a solution of NaHCO (1.20 g, 13.9 mmol) in water (100 mL) was slowly added. The aqueous phase was extracted with a mixture of iPrOH / CHCl (1:9 v / v, 8 × 100 mL). The combined organic phase was washed with brine (100 mL), dried (NaSO), filtered, and concentrated. The residue was suspended in EtO (200 mL) and sonicated for 5 min. The solid was collected by filtration and dried under high vacuum to give the title compound as a colorless solid (1.10 g, 77%). 1 H NMR (500 MHz, DMSO-d6) δ 10.86 (s, 1H), 9.64 (s, 1H), 7.39 - 7.21 (m, 2H), 7.00 - 6.92 (m, 2H), 5.14 - 4.52 (m, 1H), 3.72 (d, J = 12.8 Hz, 2H), 3.04 - 2.86 (m, 4H), 2.87 - 2.63 (m, 2H), 2.61 - 2.51 (m, 2H), 2.44 - 2.30 (m, 1H), 2.03 - 1.84 (m, 3H), 1.66 - 1.46 (m, 2H).m / z(ES + ), [M+H] + 358.2. [ka]

[0257] Additional examples of VHL-targeting LHM building blocks that can be prepared according to Scheme B3 are described below. HVB1: 5-(((S)-1-((2S,4R)-4-hydroxy-2-((4-(4-methylthiazol-5-yl)benzyl)carbamoyl)pyrrolidin-1-yl)-3,3-dimethyl-1-oxobutan-2-yl)amino)-5-oxopentanoic acid [ka]

[0258] To a solution of glutaric acid (135 mg, 1.0 mmol) in THF (10 mL) and methanol (5 mL) was added HATU (0.39 g, 1.0 mmol) and N,N-diisopropylethylamine (0.33 mL, 1.9 mmol). The reaction mixture was stirred for 5 minutes, and then (2S,4R)-1-[(2S)-2-amino-3,3-dimethylbutanoyl]-4-hydroxy-N-{[4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}pyrrolidine-2-carboxamide (0.40 g, 0.93 mmol) was added. The reaction mixture was stirred for 16 hours, then quenched with 4N dioxane (0.25 mL). The crude mixture was concentrated onto silica gel and purified by reverse-phase chromatography. LCMS C 27 H 36 N4O6S Theoretical value: 544, Measured value: m / z = 567.5 [M+Na] + .

[0259] 1H NMR (500 MHz, DMSO-d6) δ 12.01 (s, 1H), 9.00 (s, 1H), 8.58 (d, J = 6.4 Hz, 1H), 7.91 (d, J = 9.3 Hz, 1H), 7.43 (p, J = 7.8, 6.7 Hz, 4H), 5.14 (d, J = 3.7 Hz, 1H), 4.55 (d, J = 9.2 Hz, 1H), 4.53 - 4.43 (m, 2H), 4.37 (s, 1H), 4.23 (dd, J = 16.0, 5.2 Hz, 1H), 3.78 - 3.52 (m, 2H), 2.46 (s, 3H), 2.28 (dt, J = 15.7, 7.7 Hz, 1H), 2.25 - 2.15 (m, 3H), 2.05 (t, J = 10.6 Hz, 1H), 1.98 - 1.83 (m, 1H), 1.72 (h, J = 6.4 Hz, 2H), 0.95 (s, 9H). HVB2: (1r,4r)-4-{[(2S)-1-[(2S,4R)-4-hydroxy-2-({[4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}carbamoyl)pyrrolidin-1-yl]-3,3-dimethyl-1-oxobutan-2-yl]carbamoyl}cyclohexane-1-carboxylic acid [ka]

[0259] [(Dimethylamino)({[1,2,3]triazolo[4,5-b]pyridin-3-yloxy})methylidene]dimethylazanium; To a solution of hexafluoro-lambda 5-phosphanide (0.34 g, 0.89 mmol) and (1r,4r)-cyclohexane-1,4-dicarboxylic acid (154 mg, 0.89 mmol) stirred in THF:DCM (1:2 ratio) and N,N-diisopropylethylamine (0.26 g, 2.0 mmol), (2S,4R)-1-[(2S)-2-amino-3,3-dimethylbutanoyl]-4-hydroxy-N-{[4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}pyrrolidine-2-carboxamide (350 mg, 0.81 mmol) was added and stirred for 16 hours. The reaction was then quenched with excess 4N HCl in dioxane and then concentrated onto silica gel. Reverse-phase column chromatography (0-100% acetonitrile in water) afforded (1r,4r)-4-{[(2S)-1-[(2S,4R)-4-hydroxy-2-({[4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}carbamoyl)pyrrolidin-1-yl]-3,3-dimethyl-1-oxobutan-2-yl]carbamoyl}cyclohexane-1-carboxylic acid (0.17 g, 36%). LCMS: C 30 H 40 N4O6S Theoretical value: 584.73, Measured value: m / z = 607.6 [M+Na] + . HVB3: (2S,4R)-1-[(2S)-3,3-dimethyl-2-{[(1r,4r)-4-formylcyclohexyl]formamido}butanoyl]-4-hydroxy-N-{[4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}pyrrolidine-2-carboxamide [ka]

[0260] Step 1: (2S,4R)-1-[(2S)-3,3-dimethyl-2-{[(1r,4r)-4-(hydroxymethyl)cyclohexyl]formamido}butanoyl]-4-hydroxy-N-{[4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}pyrrolidine-2-carboxamide. To a solution of [(dimethylamino)({[1,2,3]triazolo[4,5-b]pyridin-3-yloxy})methylidene]dimethylazanium;hexafluoro-lambda 5-phosphanide (0.34 g, 0.89 mmol) and (1r,4r)-4-(hydroxymethyl)cyclohexane-1-carboxylic acid (141 mg, 0.89 mmol) stirred in THF:DCM (1:2 ratio) and N,N-diisopropylethylamine (0.26 g, 2.0 mmol), (2S,4R)-1-[(2S)-2-amino-3,3-dimethylbutanoyl]-4-hydroxy-N-{[4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}pyrrolidine-2-carboxamide (350 mg, 0.81 mmol) was added and stirred for 16 hours. The reaction was then quenched with two drops of 4N HCl in dioxane and then concentrated onto silica gel. Reverse phase chromatography (0-100% acetonitrile in water) afforded (2S,4R)-1-[(2S)-3,3-dimethyl-2-{[(1r,4r)-4-(hydroxymethyl)cyclohexyl]formamido}butanoyl]-4-hydroxy-N-{[4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}pyrrolidine-2-carboxamide (0.33 g, 71%). LCMS: C 30 H 42 N4O5S Theoretical value: 570.8, Measured value: m / z = 571.6 [M+H] + .

[0261] Step 2: (2S,4R)-1-[(2S)-3,3-dimethyl-2-{[(1r,4r)-4-formylcyclohexyl]formamido}butanoyl]-4-hydroxy-N-{[4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}pyrrolidine-2-carboxamide. (2S,4R)-1-[(2S)-3,3-Dimethyl-2-{[(1r,4r)-4-(hydroxymethyl)cyclohexyl]formamido}butanoyl]-4-hydroxy-N-{[4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}pyrrolidine-2-carboxamide (330 mg, 0.58 mmol) was dissolved in DCM (0.1 M) and then 1,1-bis(acetyloxy)-3-oxo-1lambda 5,2-benzoiodoxol-1-yl acetate (0.3 g, 0.7 mmol) was added. The reaction was stirred for 2 hours, then filtered through Celite and concentrated onto silica gel. Chromatography (0-10% methanol in DCM) afforded (2S,4R)-1-[(2S)-3,3-dimethyl-2-{[(1r,4r)-4-formylcyclohexyl]formamido}butanoyl]-4-hydroxy-N-{[4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}pyrrolidine-2-carboxamide (0.2 g, 61%) as a white solid. LCMS: C 30 H 40 N4O5S Theoretical value: 568.7, Measured value: m / z = 569.6 [M+H] + . Scheme B4 shows an alternative approach to generate VHL-targeting LHM building blocks via different attachment points to the LHM: [ka]

[0262] Scheme B4 begins with coupling of a linker precursor to a VHL-targeting LHM, i.e., (2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxy-N-{[2-hydroxy-4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}pyrrolidine-2-carboxamide. The VHL-targeting LHM is prepared according to the following steps: [ka]

[0263] Step 1: 2-Hydroxy-4-(4-methyl-1,3-thiazol-5-yl)benzonitrile. A solution of 4-bromo-2-hydroxybenzonitrile (25 g, 126.25 mmol), 4-methylthiazole (25.035 g, 252.5 mmol, 2.0 equiv.), and anhydrous KOAc (24.78 g, 252.5 mmol) in DMF (210.42 mL, 0.6 M) was heated in an ultrasonic bath under argon barbotate for 10 min. Pd(OAc) (0.567 g, 2.52 mmol) was then added. The resulting mixture was stirred under argon at 110° C. for 5 hours, with three additional portions of Pd(OAc) (0.283 g, 1.26 mmol) added every hour (total amount of Pd(OAc) (1.417 g, 6.31 mmol)). The reaction mixture was cooled to room temperature, filtered through Celite, diluted with water, and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (DCM / MeOH) to give 2-hydroxy-4-(4-methyl-1,3-thiazol-5-yl)benzonitrile (17.64 g, 64.6%) as a yellow solid. LCMS: C 11 H8N2OS Theoretical value: 216.3, Measured value: m / z = 217.49 [M+H] + ; 1H NMR (300 MHz, DMSO-d6) δ 11.36 (s, 1H), 9.08 (s, 1H), 7.71 (d, J = 8.1 Hz, 1H), 7.14 (d, J = 1.6 Hz, 1H), 7.08 (dd, J = 8.0, 1.7 Hz, 1H), 2.50 (s, 3H).

[0264] Step 2: 2-(Aminomethyl)-5-(4-methyl-1,3-thiazol-5-yl)phenol. To a solution of LAH (1 M in THF) (203.9 mL, 203.92 mmol) was slowly added a solution of 2-hydroxy-4-(4-methyl-1,3-thiazol-5-yl)benzonitrile (17.64 g, 81.57 mmol) in THF (203.92 mL, 0.4 M) under argon at −10° C. After the addition was complete, the reaction mixture was allowed to slowly warm to room temperature for 5 h. NaSO 4· The reaction was quenched by the addition of 10H2O and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (DCM / MeOH) to give 2-(aminomethyl)-5-(4-methyl-1,3-thiazol-5-yl)phenol (9.18 g, 52%) as an amber oil. LCMS: C 11 H 12 N2OS theoretical value: 220.3, measured value: m / z = 221.5 [M+H] + ; 1 H NMR (300 MHz, DMSO-d6) δ 8.96 (s, 1H), 7.23 - 7.15 (m, 1H), 6.87 - 6.81 (m, 2H), 3.88 (s, 2H), 2.45 (s, 3H).

[0265] Step 3: Methyl (2S,4R)-1-[(2S)-2-{[(tert-butoxy)carbonyl]amino}-3,3-dimethylbutanoyl]-4-hydroxypyrrolidine-2-carboxylate. To a solution of methyl (2S)-2-{[(tert-butoxy)carbonyl]amino}-3,3-dimethylbutanoate (41.0 g, 0.177 mol) and DIPEA (46.3 mL, 0.266 mol) in anhydrous THF (1770 mL, 0.1 M) was added HATU (70.8 g, 0.186 mol) as a solid in small portions at 10° C., forming the activated ester within 30 min. In a separate reaction vessel, a solution of (2S,4R)-4-hydroxypyrrolidine-2-carboxylate hydrochloride (48.0 g, 1.266 mol) and DIPEA (46.3 mL, 0.266 mol, 1.5 equiv.) was prepared and cooled to -45 °C under an inert atmosphere. The solution of activated ester was added dropwise over 0.5 h at -45 to 40 °C, and the reaction mixture was allowed to warm slowly to room temperature overnight. Water (ca. 500 mL) was added in one portion to quench the reaction, and the volatiles were concentrated in vacuo. The oily residue was extracted with EtOAc (3 × 400 mL), washed with saturated aqueous NaHCO (250 mL), 10% aqueous KHSO (250 mL), brine (300 mL), dried over MgSO, filtered, and solvent evaporated to give the crude product, which was purified by FC. The corresponding fractions were concentrated to give methyl (2S,4R)-1-[(2S)-2-{[(tert-butoxy)carbonyl]amino}-3,3-dimethylbutanoyl]-4-hydroxypyrrolidine-2-carboxylate as a pale yellow oil (64 g, 99%). LCMS: C 17 H 30 N2O6 theoretical value: 358.44, measured value: m / z = 359.3 [M+H] + ; 1H NMR (300 MHz, DMSO-d6) δ 6.54 (d, J = 9.3 Hz, 1H), 5.23 (d, J = 3.8 Hz, 1H), 4.42 - 4.29 (m, 2H), 4.16 (d, J = 9.4 Hz, 1H), 3.71 - 3.61 (m, 2H), 2.11 (dd, J = 12.2, 9.2 Hz, 1H), 1.95 - 1.85 (m, 1H), 1.38 (s, 10H), 0.94 (s, 9H).

[0266] Step 4: (2S,4R)-1-[(2S)-2-{[(tert-butoxy)carbonyl]amino}-3,3-dimethylbutanoyl]-4-hydroxypyrrolidine-2-carboxylic acid. To a solution of methyl (2S,4R)-1-[(2S)-2-{[(tert-butoxy)carbonyl]amino}-3,3-dimethylbutanoyl]-4-hydroxypyrrolidine-2-carboxylate (63.54 g, 0.177 mol) in THF (220 mL, 0.8 M) was immediately added LiOH·HO (14.88 g, 0.355 mol) as an aqueous solution (86 mL, 0.2 M) at room temperature. The reaction mixture was stirred at room temperature for 3 hours and monitored by TLC / UPLC. Upon completion of the reaction, 10% aqueous KHSO was added until the pH reached approximately 3. The THF was concentrated by rotary evaporation, and the residue was extracted with EtOAc (3 x 400 mL). The combined organic fractions were washed with 10% aqueous KHSO (200 mL), brine (300 mL), dried over MgSO, filtered, and evaporated to dryness. The viscous, pale yellow oily residue was sonicated with anhydrous THF (300 ml) to give an off-white precipitate, which was filtered and dried in vacuo at 50 °C to give 69.6 g of (2S,4R)-1-[(2S)-2-{[(tert-butoxy)carbonyl]amino}-3,3-dimethylbutanoyl]-4-hydroxypyrrolidine-2-carboxylic acid (69.6 g, containing approximately 15 wt% THF). LCMS: C 16 H 28 N2O6 theoretical value: 344.4, measured value: m / z = 345.2 [M+H] + ; 1H NMR (300 MHz, DMSO-d6) δ 12.43 (s, 1H), 6.49 (d, J = 9.4 Hz, 1H), 5.18 (d, J = 3.7 Hz, 1H), 4.33 (bs, 1H), 4.26 (t, J = 8.4 Hz, 1H), 4.16 (d, J = 9.4 Hz, 1H), 3.69-3.52 (m, 2H),2.18 - 2.02 (m, 1H), 1.89 (ddd, J = 13.2, 9.1, 4.6 Hz, 1H), 1.38 (s, 9H), 0.94 (s, 9H).

[0267] Step 5: tert-butyl N-[(2S)-1-[(2S,4R)-4-hydroxy-2-({[2-hydroxy-4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}carbamoyl)pyrrolidin-1-yl]-3,3-dimethyl-1-oxobutan-2-yl]carbamate. To a solution of (2S,4R)-1-[(2S)-2-{[(tert-butoxy)carbonyl]amino}-3,3-dimethylbutanoyl]-4-hydroxypyrrolidine-2-carboxylic acid (14.352 g, 41.67 mmol) in DMF (138.9 mL, 0.3 M) cooled in an ice-water bath under argon, DIPEA (10.89 mL, 62.51 mmol) and HATU (16.644 g, 43.76 mmol) were added. The resulting mixture was allowed to warm to room temperature for 0.5 hours and then added dropwise to a solution of 2-(aminomethyl)-5-(4-methyl-1,3-thiazol-5-yl)phenol (9.180 g, 41.67 mmol) and DIPEA (7.26 mL, 42.67 mmol) in DMF (83.34 mL, 0.5 M) at −40° C. under argon. After the addition, the reaction mixture was placed in a cooling bath and allowed to warm to room temperature slowly for 5 hours. The reaction was quenched by adding 5 mL of water and concentrated under reduced pressure. The residue was purified by silica gel flash chromatography (DCM / MeOH) to give (2S,4R)-1-[(2S)-2-{[(tert-butoxy)carbonyl]amino}-3,3-dimethylbutanoyl]-4-hydroxypyrrolidine-2-carboxylic acid (13.36 g, 58.64%) as a yellow solid. LCMS: C 27 H 38 N4O6S Theoretical value: 546.7, Measured value: m / z = 547.9 [M+H] +After purification by flash chromatography, the doubly acylated by-product, 2-({[(2S,4R)-1-[(2S)-2-{[(tert-butoxy)carbonyl]amino}-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}methyl)-5-(4-methyl-1,3-thiazol-5-yl)phenyl(2S)-1-(2-{[(tert-butoxy)carbonyl]amino}-3,3-dimethylbutanoyl)pyrrolidine-2-carboxylate, was also obtained. The acyl group can be cleaved according to step 5a. 1 H NMR (300 MHz, Chloroform-d) δ 9.28 (br s, 1H), 8.70 (s, 1H), 8.11 (t, J = 6.6 Hz, 1H), 7.13 (d, J = 7.8 Hz, 1H), 6.98 (d, J = 1.8 Hz, 1H), 6.88 (dd, J = 7.7, 1.8 Hz, 1H), 5.19 (d, J = 8.9 Hz, 1H), 4.77 (t, J = 7.9 Hz, 1H), 4.51 (dd, J = 15.0, 6.9 Hz, 2H), 4.12 (td, J = 20.4, 8.4 Hz, 3H), 3.57 (dd, J = 11.4, 3.6 Hz, 1H), 2.85 (br s, 2H), 2.53 (m, 4H), 2.11 (dd, J = 13.5, 8.1 Hz, 1H), 1.56 - 1.43 (m, 2H), 1.41 (s, 9H), 0.84 (s, 9H).

[0268] Step 5a: tert-butyl N-[(2S)-1-[(2S,4R)-4-hydroxy-2-({[2-hydroxy-4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}carbamoyl)pyrrolidin-1-yl]-3,3-dimethyl-1-oxobutan-2-yl]carbamate. To a solution of 2-({[(2S,4R)-1-[(2S)-2-{[(tert-butoxy)carbonyl]amino}-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}methyl)-5-(4-methyl-1,3-thiazol-5-yl)phenyl(2S)-1-(2-{[(tert-butoxy)carbonyl]amino}-3,3-dimethylbutanoyl)pyrrolidine-2-carboxylate (3 g, 3.5 mmol) in MeOH (70 mL, 0.05 M) was added KCO (0.484 g, 3.5 mmol). The reaction mixture was stirred at room temperature for 12 hours. The reaction mixture was concentrated, and the residue was diluted with water, neutralized with KHSO, extracted with DCM (x3), and the resulting organic layer was dried over NaSO and concentrated under reduced pressure. The resulting residue was purified by silica gel flash chromatography (5% DCM / MeOH) to afford tert-butyl N-[(2S)-1-[(2S,4R)-4-hydroxy-2-({[2-hydroxy-4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}carbamoyl)pyrrolidin-1-yl]-3,3-dimethyl-1-oxobutan-2-yl]carbamate (2.14 g, 99%) as a yellow solid. LCMS: C 27 H 38 N4O6S Theoretical value: 546.7, Measured value: m / z = 547.2 [M+H] + ; 1H NMR (300 MHz, Chloroform-d) δ 9.29 (s, 1H), 8.80 (s, 1H), 8.19 (s, 1H), 7.14 (d, J = 7.8 Hz, 1H), 6.98 (d, J = 1.8 Hz, 1H), 6.87 (dd, J = 7.7, 1.8 Hz, 1H), 5.14 (d, J = 8.9 Hz, 1H), 4.81 (t, J = 7.9 Hz, 1H), 4.56 (q, J = 7.8 Hz, 2H), 4.12 (td, J = 13.6, 12.6, 4.7 Hz, 3H), 3.56 (dd, J = 11.4, 3.5 Hz, 1H), 2.56 (s, 4H), 2.19 - 2.05 (m, 1H), 0.83 (s, 10H).

[0269] Step 6: (2S,4R)-1-[(2S)-2-amino-3,3-dimethylbutanoyl]-4-hydroxy-N-{[2-hydroxy-4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}pyrrolidine-2-carboxamide. To a solution of tert-butyl N-[(2S)-1-[(2S,4R)-4-hydroxy-2-({[2-hydroxy-4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}carbamoyl)pyrrolidin-1-yl]-3,3-dimethyl-1-oxobutan-2-yl]carbamate (2.14 g) (5.27 g, 9.64 mmol) in DCM (48.2 mL, 0.2 M) cooled in an ice-water bath was added 2 M HCl in EtO (38.56 mL, 77.12 mmol). The reaction mixture was stirred at room temperature for 2 hours. The solid was triturated in an ultrasonic bath, filtered off, washed on the filter with DCM and dried under vacuum to give (2S,4R)-1-[(2S)-2-amino-3,3-dimethylbutanoyl]-4-hydroxy-N-{[2-hydroxy-4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}pyrrolidine-2-carboxamide (5.05 g, 99%) as a white solid. LCMS: C 22 H 30 N4O4S Theoretical value: 446.6, Measured value: m / z = 447.7 [M+H] + ;1 H NMR (300 MHz, D2O) δ 9.50 (d, J = 1.0 Hz, 1H), 7.30 (d, J = 7.8 Hz, 1H), 7.04 - 6.89 (m, 2H), 4.58 (dd, J = 9.9, 7.6 Hz, 1H), 4.52 (s, 1H), 4.44 - 4.23 (m, 2H), 4.08 (s, 1H), 3.80 (d, J = 11.9 Hz, 1H), 3.68 (dd, J = 11.9, 3.4 Hz, 1H), 3.46 (q, J = 7.1 Hz, 1H), 2.45 (s, 3H), 2.28 (dd, J = 13.9, 7.7 Hz, 1H), 2.01 (ddd, J = 14.0, 9.9, 4.2 Hz, 1H), 1.08 (t, J = 7.1 Hz, 2H), 0.98 (s, 9H).

[0270] Step 7: (2S,4R)-1-[(2S)-2-[(1-Fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxy-N-{[2-hydroxy-4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}pyrrolidine-2-carboxamide. To a solution of 1-fluorocyclopropane-1-carboxylic acid (1.337 g, 12.85 mmol) in DMF (128 mL, 0.1 M) cooled in an ice-water bath was added HATU (5.129 g, 13.49 mmol) and DIPEA (3.36 mL, 19.27 mmol). The resulting mixture was allowed to warm to room temperature for 0.5 hours, and then added dropwise to a solution of (2S,4R)-1-[(2S)-2-amino-3,3-dimethylbutanoyl]-4-hydroxy-N-{[2-hydroxy-4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}pyrrolidine-2-carboxamide (5.05 g, quantitative yield) (6.674 g, 12.85 mmol) and DIPEA (7.83 mL, 44.97 mmol) in DMF (42 mL, 0.3 M) at −40° C. After the addition, the reaction mixture was placed in a cooling bath and allowed to warm slowly to room temperature over 16 hours. The reaction mixture was then diluted with water and extracted with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (DCM / MeOH) to give (2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxy-N-{[2-hydroxy-4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}pyrrolidine-2-carboxamide (5.05 g, 74%) as a yellow solid. LCMS: C 26 H 33 N4O5SF Theoretical value: 532.6, Measured value: m / z = 533.8 [M+H] + ; 1H NMR (300 MHz, Chloroform-d) δ 9.29 (s, 1H), 8.70 (s, 1H), 8.09 (dd, J = 7.5, 5.5 Hz, 1H), 7.13 (d, J = 7.8 Hz, 1H), 7.01 (dd, J = 8.5, 3.7 Hz, 1H), 6.98 (d, J = 1.8 Hz, 1H), 6.88 (dd, J = 7.7, 1.8 Hz, 1H), 4.73 (t, J = 7.9 Hz, 1H), 4.53 (br s, 1H), 4.51 - 4.40 (m, 2H), 4.18 (dd, J = 14.6, 5.4 Hz, 1H), 3.99 (d, J = 11.3 Hz, 1H), 3.63 (dd, J = 11.2, 3.7 Hz, 1H), 2.53 (s, 3H), 2.47 (ddd, J = 12.9, 7.9, 4.6 Hz, 1H), 2.15 - 2.01 (m, 1H), 1.36 - 1.22 (m, 4H), 0.91 (s, 9H).

[0271] Additional examples of VHL-targeting LHM building blocks that can be prepared according to Scheme B4 are described below. HVB4: 6-(2-(((2S,4R)-1-((S)-2-(1-fluorocyclopropane-1-carboxamido)-3,3-dimethylbutanoyl)-4-hydroxypyrrolidine-2-carboxamido)methyl)-5-(4-methylthiazol-5-yl)phenoxy)hexanoic acid [ka]

[0272] Step 1: tert-butyl 6-[2-({[(2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}methyl)-5-(4-methyl-1,3-thiazol-5-yl)phenoxy]hexanoate. To a solution of (2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxy-N-{[2-hydroxy-4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}pyrrolidine-2-carboxamide (1.29 g, 2.42 mmol, 1.0 equiv.) in anhydrous DMF (16 mL, 0.15 M) was added CsCO (1.184 g, 3.63 mmol, 1.5 equiv.) and tert-butyl 6-bromohexanoate (CAS 65868-63-5, 0.85 g, 3.4 mmol, 1.4 equiv.). The reaction mixture was purged with argon, sealed, and stirred at 25 °C for 16 h. The solid was filtered, washed with EtOAc (5 mL), and discarded. The resulting filtrate was diluted with water (60 mL) and extracted with ethyl acetate (3 x 20 mL). The combined organic layers were washed with brine (20 mL), dried over Na2SO4, filtered, and concentrated under reduced pressure to give the crude product, which was purified by flash chromatography (hexane / ethyl acetate) to give 1.38 g of the desired product as a white solid (81.1% yield). ESI (+) [M+H] + =703.8

[0273] Step 2: 6-[2-({[(2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}methyl)-5-(4-methyl-1,3-thiazol-5-yl)phenoxy]hexanoic acid. To a solution of tert-butyl 6-[2-({[(2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}methyl)-5-(4-methyl-1,3-thiazol-5-yl)phenoxy]hexanoate (1.38 g, 1.96 mmol, 1.0 equiv) in anhydrous DCM (147.3 mL, 0.4 M) was added HCl in diethyl ether (2 M, 30 mL). The reaction mixture was stirred at room temperature overnight. The solvent was evaporated under reduced pressure to give a residue that was dissolved in THF (10 mL), triturated with aqueous ammonia (3 M, 5 mL) for 10 min, and concentrated again. The resulting crude material was purified by reverse-phase flash chromatography to afford 6-(2-(((2S,4R)-1-((S)-2-(1-fluorocyclopropane-1-carboxamido)-3,3-dimethylbutanoyl)-4-hydroxypyrrolidine-2-carboxamido)methyl)-5-(4-methylthiazol-5-yl)phenoxy)hexanoic acid (614 mg, 48%) as an off-white amorphous solid. LCMS 254 nm, RT=2.59 min, 95.62% purity, ESI(+)=647.13 [M+H] + ; 1H NMR (300 MHz, Methanol-d4) δ 8.86 (s, 1H), 7.50 (dd, J = 19.7, 9.1 Hz, 2H), 7.07 - 6.92 (m, 2H), 4.80 - 4.66 (m, 1H), 4.63 (t, J = 8.3 Hz, 1H), 4.50 (d, J = 3.2 Hz, 1H), 4.42 (d, J = 9.6 Hz, 1H), 4.07 (t, J = 6.2 Hz, 2H), 3.91 - 3.62 (m, 2H), 2.48 (s, 3H), 2.34 (t, J = 7.2 Hz, 2H), 2.27 - 2.02 (m, 2H), 1.87 (p, J = 6.6 Hz, 2H), 1.65 (dp, J = 33.1, 8.5, 7.8 Hz, 4H), 1.47 - 1.18 (m, 5H), 1.03 (s, 10H). HVB5: 8-(2-(((2S,4R)-1-((S)-2-(1-fluorocyclopropane-1-carboxamido)-3,3-dimethylbutanoyl)-4-hydroxypyrrolidine-2-carboxamido)methyl)-5-(4-methylthiazol-5-yl)phenoxy)octanoic acid

[0274] HVB5 was prepared following the same method as HVB4, except hexanoic acid was replaced with octanoic acid to give the title compound. LCMS: C 34 H 47 FN4O7S Theoretical value: 674.3, Measured value: m / z = 672.7 [MH] - HVB6: 10-(2-(((2S,4R)-1-((S)-2-(1-fluorocyclopropane-1-carboxamido)-3,3-dimethylbutanoyl)-4-hydroxypyrrolidine-2-carboxamido)methyl)-5-(4-methylthiazol-5-yl)phenoxy)decanoic acid [ka]

[0275] Step 1: tert-Butyl 10-bromodecanoate. To a solution of 10-bromodecanoic acid (CAS: 50530-12-6, 10.0 g, 39.8 mmol, 1.0 equiv.) in anhydrous dichloromethane (0.25 M) under nitrogen at 0 °C was added tert-butyl alcohol (18.9 mL, 199 mmol, 5.0 equiv.) followed by DMAP (0.96 g, 4.0 mmol, 0.1 equiv.). After 5 min, dicyclohexylcarbodiimide (9.04 g, 44 mmol, 1.1 equiv.) was added to the solution at 0 °C. The reaction mixture was allowed to warm to room temperature and stirred for 20 h. The volatiles were concentrated, and the crude material was then loaded directly onto silica (5-10% EtOAc in hexanes). The desired product was isolated (9.0 g), contaminated with DCC ( 1 by H NMR analysis). Further purification was carried out by FC (eluent: 10-50% DCM in hexane) to give 5.8 g of tert-butyl 10-bromodecanoate (47% yield) as a colorless oil. 1 H NMR (300 MHz, Chloroform-d) δ 3.42 (t, J = 6.9 Hz, 2H), 2.22 (t, J = 7.5 Hz, 2H), 1.87 (p, J = 6.9 Hz, 2H), 1.68 - 1.51 (m, 2H), 1.46 (s, 9H), 1.45 - 1.37 (m, 2H), 1.31 (s, 8H).

[0276] Step 2: tert-Butyl 10-[2-({[(2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}methyl)-5-(4-methyl-1,3-thiazol-5-yl)phenoxy]decanoate. To a solution of (2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxy-N-{[2-hydroxy-4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}pyrrolidine-2-carboxamide (0.8 g, 1.5 mmol, 1.0 equiv.) in anhydrous DMF (15 mL, 0.1 M) was added CsCO (0.734 g, 2.25 mmol, 1.5 equiv.) and tert-butyl 10-bromodecanoate (0.646 g, 2.10 mmol, 1.4 equiv.). The reaction mixture was purged with argon, sealed, and stirred at 25 °C for 16 h. The solid was filtered, washed with EtOAc (5 mL), and discarded. The resulting filtrate was diluted with water (60 mL) and extracted with ethyl acetate (3 x 20 mL). The combined organic layers were washed with brine (20 mL), dried over Na2SO4, filtered, and concentrated under reduced pressure to give the crude product, which was purified by flash chromatography (hexane / ethyl acetate) to give 0.99 g of the desired product as a white solid (87.1% yield). ESI(+)[M+H] + =782.4; 1H NMR (300 MHz, Chloroform-d) δ 8.70 (s, 1H), 7.34 (d, J = 7.7 Hz, 1H), 7.25 (t, J = 5.9 Hz, 1H), 7.05 (dd, J = 8.7, 3.6 Hz, 1H), 6.96 (dd, J = 7.6, 1.6 Hz, 1H), 6.89 (d, J = 1.6 Hz, 1H), 4.76 (t, J = 7.7 Hz, 1H), 4.61 - 4.49 (m, 3H), 4.44 (dd, J = 14.8, 5.4 Hz, 1H), 4.09 - 3.97 (m, 3H), 3.64 (dd, J = 11.3, 3.9 Hz, 1H), 2.65 - 2.56 (m, 1H), 2.55 (s, 3H), 2.22 (t, J = 7.5 Hz, 2H), 2.15 (d, J = 2.6 Hz, 1H), 1.87 (p, J = 6.6 Hz, 2H), 1.59 (t, J = 7.1 Hz, 2H), 1.52 (m, 2H), 1.46 (s, 9H), 1.43 - 1.32 (m, 10H), 0.96 (s, 9H).

[0277] Step 3: 10-[2-({[(2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}methyl)-5-(4-methyl-1,3-thiazol-5-yl)phenoxy]decanoic acid. To a solution of tert-butyl 10-[2-({[(2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}methyl)-5-(4-methyl-1,3-thiazol-5-yl)phenoxy]decanoate (0.993 g, 1.31 mmol, 1.0 equiv) in anhydrous DCM (6.5 mL, 0.2 M) was added TFA (2.00 mL, 26.17 mmol, 20 equiv). The reaction was stirred at 25° C. for 3 hours. The reaction was evaporated in vacuo and the resulting oil was treated with aqueous ammonia (20%, 5 mL). After stirring for 1 hour, an oil formed. The supernatant was decanted. The oil was dried in vacuo and purified using reverse-phase flash chromatography (20% to 60% acetonitrile / 0.1% formic acid in water) to give 0.703 g of the title compound (76.5% yield) as a white solid. LCMS (254 nm): RT = 3.037 min, 100.00% purity, ESI [M+H] + =703.18; 1H NMR (300 MHz, DMSO-d6) δ 12.00 (s, 1H), 8.99 (s, 1H), 8.51 (t, J = 5.9 Hz, 1H), 7.41 (d, J = 7.8 Hz, 1H), 7.31 (dd, J = 9.3, 2.9 Hz, 1H), 7.01 (d, J = 1.7 Hz, 1H), 6.96 (dd, J = 7.7, 1.6 Hz, 1H), 5.19 (s, 1H), 4.66 - 4.57 (m, 1H), 4.53 (t, J = 8.2 Hz, 1H), 4.36 (s, 1H), 4.25 (qd, J = 16.7, 5.9 Hz, 2H), 4.05 (t, J = 6.3 Hz, 2H), 3.73 - 3.56 (m, 2H), 2.47 (s, 3H), 2.19 (t, J = 7.3 Hz, 2H), 2.15 - 2.09 (m, 1H), 1.93 (ddd, J = 13.0, 8.9, 4.5 Hz, 1H), 1.76 (p, J = 6.4 Hz, 2H), 1.57 - 1.38 (m, 6H), 1.38 - 1.15 (m, 12H), 0.97 (s, 9H). HVB7: 3-{2-[2-({[(2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3-methylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}methyl)-5-(4-methyl-1,3-thiazol-5-yl)phenoxy]ethoxy}propanoic acid [ka]

[0278] Step 1: tert-Butyl 3-(2-bromoethoxy)propanoate. A solution of tert-butyl 3-(2-hydroxyethoxy)propanoate (3.0 g, 15.7 mmol, 1 equiv.) and carbon tetrabromide (3.9 g, 11.87 mmol, 1.5 equiv.) in dichloromethane (15 mL, 0.5 mL) was prepared in a 50 mL flask and cooled to 0 °C. With vigorous stirring, triphenylphosphine (3.1 g, 11.87 mmol, 1.5 equiv.) was added portionwise via powder funnel over 30 min. Upon addition of the phosphine, the colorless solution turned light brown and was stirred at room temperature for an additional 2 h. The mixture was concentrated and quickly added to stirred hexanes (50 mL). The white precipitate was filtered, the remaining solution was concentrated and the resulting residue was purified by FC (eluting with DCM / MeOH - 9 / 1) to give 4.1 g of the desired product (DP) as a white solid (yield 62.8%).

[0279] Step 2: tert-butyl 3-{2-[2-({[(2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}methyl)-5-(4-methyl-1,3-thiazol-5-yl)phenoxy]ethoxy}propanoate. To a solution of (2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxy-N-{[2-hydroxy-4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}pyrrolidine-2-carboxamide (1.5 g, 2.82 mmol, 1.0 equiv.) in DMF (18.77 mL, 0.15 M) was added CsCO (1.376 g, 4.22 mmol, 1.5 equiv.) and tert-butyl 3-(2-bromoethoxy)propanoate (2.18 g, 3.94 mmol, 1.4 equiv.). The resulting mixture was stirred at room temperature overnight. The reaction mixture was diluted with water and extracted with EtOAc (3 times), the organic layer was dried over Na2SO4 and concentrated, and the residue was purified by FC eluting with DCM / MeOH-9 / 1 to give 1.8 g of the desired product as a pale yellow oil (quantitative yield). UPLC (12 min, 254 nm): RT = 6.25 min, 100% purity, ESI [M+H + ] + =705.55

[0280] Step 3: 3-{2-[2-({[(2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3-methylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}methyl)-5-(4-methyl-1,3-thiazol-5-yl)phenoxy]ethoxy}propanoic acid. To a solution of tert-butyl 3-{2-[2-({[(2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}methyl)-5-(4-methyl-1,3-thiazol-5-yl)phenoxy]ethoxy}propanoate (1.8 g, 2.64 mmol, 1 equiv) in DCM (17.6 mL, 0.15 M) was added TFA (13.2 mL, 0.2 M) dropwise at 0° C. The reaction mixture was stirred at room temperature for 1 hour. The reaction mixture was concentrated, and the residue was diluted with 50 mL of aqueous NH4OH (to pH=11) and placed in an ultrasonic bath for 0.5 hour, followed by simple stirring for 1 hour. The resulting slurry was concentrated and purified twice by RF: first, eluted with ACN / H2O, yielding 0.3 g of the desired product; second, eluted with ACN / H2O (0.1% formic acid), yielding 1 g of the desired product. After neutralization with NH4OH, the product was obtained in the form of an ammonium salt, which was dissociated with formic acid during the second purification. All amounts combined gave 1.3 g of the desired product (76% yield). LCMS (254 nm): RT = 2.29 min: 99% purity, ESI [M+H] + =649.10; 1H NMR (300 MHz, Chloroform-d) δ 8.70 (s, 1H), 7.37 (d, J = 7.8 Hz, 2H), 7.09 - 7.03 (m, 1H), 6.99 (dd, J = 7.7, 1.6 Hz, 1H), 6.91 (d, J = 1.6 Hz, 1H), 4.76 (t, J = 8.1 Hz, 1H), 4.64 - 4.51 (m, 3H), 4.41 (dd, J = 14.3, 5.2 Hz, 1H), 4.20 (t, J = 4.2 Hz, 2H), 4.03 (d, J = 11.3 Hz, 1H), 3.89 (td, J = 8.6, 7.8, 4.4 Hz, 4H), 3.77 (dd, J = 11.3, 3.7 Hz, 1H), 2.66 (ddd, J = 19.7, 14.9, 5.1 Hz, 2H), 2.54 (s, 3H), 2.33 - 2.14 (m, 2H), 1.41 - 1.23 (m, 4H), 1.03 (s, 9H).

[0281] HVB8: 1-(2-(((2S,4R)-1-((S)-2-(1-fluorocyclopropane-1-carboxamido)-3,3-dimethylbutanoyl)-4-hydroxypyrrolidine-2-carboxamido)methyl)-5-(4-methylthiazol-5-yl)phenoxy)-3,6,9,12,15-pentaoxaoctadecanoic acid

[0282] HVB8 was prepared in a manner similar to HVB7 by replacing tert-butyl 3-{2-[2-(2-bromoethoxy)ethoxy]ethoxy}propanoate with tert-butyl 3-(2-hydroxyethoxy)propanoate in step 1 to afford the title compound as a white solid. LCMS (254 nm): RT = 2.27 min, 96.35% purity, ESI [M+H] + =736.88.

[0284] 1H NMR (300 MHz, DMSO-d6) δ 8.98 (s, 1H), 8.51 (t, J = 6.0 Hz, 1H), 7.41 (d, J = 7.8 Hz, 1H), 7.31 (dd, J = 9.2, 2.9 Hz, 1H), 7.04 (d, J = 1.7 Hz, 1H), 6.97 (dd, J = 7.7, 1.6 Hz, 1H), 5.19 (s, 1H), 4.60 (d, J = 9.1 Hz, 1H), 4.51 (t, J = 8.2 Hz, 1H), 4.35 (s, 1H), 4.28 (d, J = 6.1Hz, 1H), 4.25 - 4.14 (m, 3H), 3.79 (dd, J = 5.8, 3.4 Hz, 2H), 3.66 - 3.46 (m, 12H), 2.46 (s, 3H), 2.42 (t, J = 6.3 Hz, 2H), 2.10 (dd, J = 13.0, 8.0 Hz, 1H), 1.92 (ddd, J = 13.1, 9.0, 4.4 Hz, 1H), 1.49 - 1.28 (m, 2H), 1.21 (tq, J = 8.4, 4.6, 3.8 Hz, 2H), 0.96 (s, 9H).

[0283] HVB9: tert-butyl 1-(2-(((2S,4R)-1-((S)-2-(1-fluorocyclopropane-1-carboxamido)-3,3-dimethylbutanoyl)-4-hydroxypyrrolidine-2-carboxamido)methyl)-5-(4-methylthiazol-5-yl)phenoxy)-3,6,9,12,15-pentaoxaoctadecanoate

[0284] HVB9 was prepared in a manner similar to HVB7 by replacing tert-butyl 1-bromo-3,6,9,12,15-pentaoxaoctadecanoate with tert-butyl 3-(2-hydroxyethoxy)propanoate in step 1 to give the title compound as a white solid. LCMS (254 nm): RT = 2.27 min, 99.8% purity, ESI (+) [M+H] + =825.21

[0287] 1 H NMR (300 MHz, DMSO-d6) δ 8.98 (s, 1H), 8.50 (t, J = 6.0 Hz, 1H), 7.41 (d, J = 7.8 Hz, 1H), 7.29 (dd, J = 9.4, 2.9 Hz, 1H), 7.04 (d, J = 1.7 Hz, 1H), 6.96 (dd, J = 7.8, 1.6 Hz, 1H), 4.60 (d, J = 9.2 Hz, 1H), 4.51 (t, J = 8.2 Hz, 1H), 4.35 (s, 1H), 4.28 (d, J = 6.0 Hz, 1H), 4.24 - 4.11 (m, 3H), 3.79 (dd, J = 5.5, 3.7 Hz, 2H), 3.67 - 3.42 (m, 22H), 2.46 (s, 3H), 2.42 (t, J = 6.4 Hz, 2H), 2.13 - 2.03 (m, 1H), 1.96 - 1.86 (m, 1H),1.46 - 1.27 (m, 2H), 1.23 (dq, J = 8.6, 4.1 Hz, 2H), 0.96 (s, 9H). HVB10: 3-{[(2S)-1-[(2S,4R)-4-hydroxy-2-{[(1S)-1-[4-(4-methyl-1,3-thiazol-5-yl)phenyl]ethyl]carbamoyl}pyrrolidin-1-yl]-3,3-dimethyl-1-oxobutan-2-yl]carbamoyl}propanoic acid [ka]

[0285] To a solution of [(dimethylamino)({[1,2,3]triazolo[4,5-b]pyridin-3-yloxy})methylidene]dimethylazanium;hexafluoro-lambda 5-phosphanide (1.41 g, 3.71 mmol) and succinic acid (398 mg, 3.37 mmol) stirred in THF:DCM (1:2 ratio) was added (2S,4R)-1-[(2S)-2-amino-3,3-dimethylbutanoyl]-4-hydroxy-N-{[4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}pyrrolidine-2-carboxamide (1.5 g, 3.37 mmol). N,N-Diisopropylethylamine (0.72 mL, 8.43 mmol) was added and the reaction was stirred for 16 hours. The reaction was then quenched with excess 4N HCl in dioxane and then concentrated onto silica gel. Reverse phase column chromatography (0-100% acetonitrile in water) afforded the title compound. LCMS: C 27 H 36 N4O6S Theoretical value: 544.24, Measured value: m / z = 545.6 [M+H] + . HVB11: 3-[3-[[(1S)-1-[(2S,4R)-4-hydroxy-2-[[(1S)-1-[4-(4-methylthiazol-5-yl)phenyl]ethyl]carbamoyl]pyrrolidine-1-carbonyl]-2,2-dimethyl-propyl]amino]-3-oxo-propoxy]propanoic acid [ka]

[0286] To a solution of 3-(2-carboxyethoxy)propanoic acid (1.5 g, 9.4 mmol) and HATU (2.6 g, 6.9 mmol) in DCM (30 mL), DIPEA (5.3 mL, 31 mmol) was slowly added, and the solution was stirred at room temperature for 5 minutes. To this mixture, (2S,4R)-1-[(2S)-2-amino-3,3-dimethyl-butanoyl]-4-hydroxy-N-[(1S)-1-[4-(4-methylthiazol-5-yl)phenyl]ethyl]pyrrolidine-2-carboxamide; hydrochloride salt 2 (3.0 g, 6.2 mmol) was added, and the reaction mixture was stirred for 30 minutes. The mixture was diluted with 1 M NaOH (5.0 mL) and stirred for 5 minutes. Next, the mixture was acidified to pH 5 using 5% citric acid. The layers were separated and the aqueous layer was extracted with EtOAc (7 x 50 mL) and DCM (3 x 50 mL). The combined organic layers were dried (sodium sulfate), filtered, and concentrated under reduced pressure. The material was purified by reverse phase chromatography on C18 using a 10-30% gradient of MeCN and water (containing 0.1% ammonium formate / formic acid) to give the title compound as a solid (1.28 g, 35%). MS (ESI) [M+H] + =589.3.

[0290] 1 H NMR (500 MHz, DMSO) δ 8.99 (s, 1H), 8.39 (d, J = 7.8 Hz, 1H), 7.87 (d, J = 9.3 Hz, 1H), 7.47 - 7.41 (m, 2H), 7.39 (s, 2H), 4.92 (p, J = 7.0 Hz, 1H), 4.53 (d, J = 9.4 Hz, 1H), 4.44 (t, J = 8.0 Hz, 1H), 4.28 (s, 1H), 3.65 - 3.49 (m, 6H), 2.46 (s, 3H), 2.37 (t, J = 6.7 Hz, 2H), 2.39 - 2.31 (m, 1H), 2.05 - 1.99 (m, 1H), 1.80 (ddd, J = 12.9, 8.4, 4.7 Hz, 1H), 1.37 (t, J = 8.2 Hz, 3H), 0.94 (s, 9H). HVB12: 4-[2-({[(2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}methyl)-5-(4-methyl-1,3-thiazol-5-yl)phenoxy]butanoic acid [ka]

[0287] Step 1: Ethyl 4-[2-({[(2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}methyl)-5-(4-methyl-1,3-thiazol-5-yl)phenoxy]butanoate. (2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxy-N-{[2-hydroxy-4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}pyrrolidine-2-carboxamide (50.00 mg, 0.09 mmol) and potassium carbonate (20.73 mg, 0.15 mmol) were combined and suspended in N,N-dimethylformamide (2.00 mL). Ethyl 4-bromobutanoate (0.02 mL, 21.97 mg, 0.11 mmol) was added and stirred at room temperature for 3 days. Quenched with water and extracted with ethyl acetate. Washed twice more with water, then once with brine. Dried over sodium sulfate, filtered, and concentrated. The reaction was carried on crude to the next step. 1H NMR (500 MHz, Chloroform-d) δ 7.35 (d, J = 7.7 Hz, 1H), 6.99 (dd, J = 7.7, 1.6 Hz, 2H), 4.78 (t, J = 7.7 Hz, 2H), 4.63 - 4.47 (m, 3H), 4.47 - 4.38 (m, 1H), 4.10 (d, J = 5.7 Hz, 7H), 4.07 (s, 4H), 3.69 - 3.58 (m, 1H), 3.50 (t, J = 6.5 Hz, 5H), 2.20 (p, J = 6.8 Hz, 7H), 2.12 (s, 2H), 1.59 (s, 4H), 1.29 (t, J = 7.2 Hz, 13H), 0.96 (s, 8H).

[0288] Step 2: 4-[2-({[(2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}methyl)-5-(4-methyl-1,3-thiazol-5-yl)phenoxy]butanoic acid. Ethyl 4-[2-({[(2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}methyl)-5-(4-methyl-1,3-thiazol-5-yl)phenoxy]butanoate (50.00 mg, 0.08 mmol) was dissolved in tetrahydrofuran (2.00 mL) and water (0.50 mL), and lithium hydroxide hydrate (32.44 mg, 0.77 mmol) was added. The mixture was stirred at room temperature for 2 days. The mixture was quenched with saturated ammonium chloride and extracted with ethyl acetate. The mixture was washed with brine and then dried over sodium sulfate. Filtration and concentration to a white solid gave 4-[2-({[(2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}methyl)-5-(4-methyl-1,3-thiazol-5-yl)phenoxy]butanoic acid (0.0400 g, 83.6%). ESI calculated 618.25; found 641.7 (M+Na+ ) HVB13: 6-{[(2S)-1-[(2S,4R)-4-hydroxy-2-{[(1S)-1-[4-(4-methyl-1,3-thiazol-5-yl)phenyl]ethyl]carbamoyl}pyrrolidin-1-yl]-3,3-dimethyl-1-oxobutan-2-yl]carbamoyl}hexanoic acid [ka]

[0289] To a solution of (2S,4R)-1-[(2S)-2-amino-3,3-dimethyl-butanoyl]-4-hydroxy-N-[(1S)-1-[4-(4-methylthiazol-5-yl)phenyl]ethyl]pyrrolidine-2-carboxamide hydrochloride salt 2 (1.75 g, 3.64 mmol), heptanedioic acid (874 mg, 5.46 mmol), and HATU (1.94 g, 5.09 mmol) in DCM (70.0 mL) was added DIPEA (3.11 mL, 18.2 mmol) at 0 °C, and the reaction mixture was stirred for 2 h. The mixture was diluted with 1 M NaOH (50 mL) and stirred for 1 h. The layers were separated, and the organic layer was extracted with 1 M NaOH (2 × 30 mL). The combined aqueous layer was acidified to pH 5-6 and extracted with EtOAc (5 × 50 mL). The combined organic layers were dried (sodium sulfate), filtered, and concentrated under reduced pressure. This material was further purified by reverse phase chromatography on C18 using a 10-60% gradient of MeCN and water (containing 0.1% ammonium formate / formic acid) to afford the title compound as a solid (0.924 g, 43%). LCMS: C 30 H 42 N4O6S Theoretical value: 586.75, Measured value: m / z = 587.3 [M+H] + .

[0294] 1H NMR (500 MHz, DMSO) δ 8.99 (s, 1H), 8.37 (d, J = 7.8 Hz, 1H), 7.79 (d, J = 9.3 Hz, 1H), 7.46 - 7.41 (m, 2H), 7.40 - 7.36 (m, 2H), 4.92 (p, J = 7.0 Hz, 1H), 4.52 (d, J = 9.4 Hz, 1H), 4.43 (t, J = 8.1 Hz, 1H), 4.30 - 4.26 (m, 1H), 3.65 - 3.57 (m, 2H), 3.46 - 3.33 (m, 1H), 2.46 (s, 3H), 2.28 - 2.20 (m, 1H), 2.18 (t, J = 7.4 Hz, 2H), 2.15 - 2.06 (m, 1H), 2.04 - 1.97 (m, 1H), 1.80 (ddd, J = 12.9, 8.5, 4.7 Hz, 1H), 1.54 - 1.42 (m, 4H), 1.38 (d, J = 7.0 Hz, 3H), 1.28 - 1.20 (m, 2H), 0.94 (s, 9H). HVB14: (3S)-3-{[(2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}-3-[4-(4-methyl-1,3-thiazol-5-yl)phenyl]propanoic acid [ka]

[0290] Step 1: Methyl (3S)-3-amino-3-(4-bromophenyl)propanoate hydrochloride. To a solution of (3S)-3-(4-bromophenyl)-3-{[(tert-butoxy)carbonyl]amino}propanoic acid (8 g, 1.453 mmol, 1.0 equiv.) in MeOH (140 mL, 0.3 M) was slowly added 3 M HCl in MeOH (200 mL, 0.15 M) cooled to 0 °C. The mixture was stirred at room temperature for 16 h. The MeOH was then removed by evaporation in vacuo, and the resulting residue was triturated with EtO to give the desired product, methyl (3S)-3-amino-3-(4-bromophenyl)propanoate hydrochloride (90% yield), as a foam-like white solid: ESI(+)[M+H] + =257.9 and 259.9 (Br pattern); 1H NMR (300 MHz, DMSO-d6): 8.91 (d, J = 5.5 Hz, 3H), 7.62 (d, J = 8.5 Hz, 2H), 7.54 (d, J = 8.6 Hz, 2H), 4.57 (q, J = 5.5, 4.9 Hz, 1H), 3.54 (s, 3H), 3.25 (dd, J = 16.4, 5.6 Hz, 1H), 3.03 (dd, J = 16.3Hz, 9.0Hz, 1H). Step 2: Methyl (3S)-3-(4-bromophenyl)-3-{[(2S,4R)-1-[(2R)-2-{[(tert-butoxy)carbonyl]amino}-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}propanoate

[0291] 1. To a mixture of (2S,4R)-1-[(2R)-2-{[(tert-butoxy)carbonyl]amino}-3,3-dimethylbutanoyl]-4-hydroxypyrrolidine-2-carboxylic acid (11.925 g, 34.628 mmol, 1.20 equiv.) and DIPEA (7.5 mL, 1.5 equiv.) in DMF (0.17 M) was added HATU (11.52 g, 30.298 mmol, 1.05 equiv.) dissolved in DMF (0.15 M) slowly at 0° C. The reaction was stirred at room temperature for 30 min.

[0292] 2. To a solution of methyl (3S)-3-amino-3-(4-bromophenyl)propanoate hydrochloride (8.5 g, 28.85 mmol, 1.0 equiv) in DMF (55 mL, 0.6 M) was added DIPEA (20.11 mL, 4 equiv) at −40° C., and the mixture was stirred at −40° C. for 5 minutes.

[0293] 3. Reactant 1 was slowly added to Reactant 2 at -40° C. The mixture was stirred at room temperature for 16 hours.

[0294] The reaction mixture was diluted with water and then extracted with DCM. The organic layer was washed with brine and dried under Na2SO4. The resulting crude was purified by flash chromatography eluting with DCM / MeOH-9 / 1 to give the product, methyl (3S)-3-(4-bromophenyl)-3-{[(2S,4R)-1-[(2R)-2-{[(tert-butoxy)carbonyl]amino}-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}propanoate (71% yield) as a pale yellow solid. ESI(+) [M+H] + =585.85.

[0300] 1 H NMR (300 MHz, DMSO-d6) δ 8.50 (d, J = 8.1 Hz, 1H), 7.52 - 7.46 (m, 2H), 7.30 - 7.21 (m, 2H), 6.45 (d, J = 9.2 Hz, 1H), 5.17 - 5.07 (m, 2H), 4.36 (t, J = 8.0 Hz, 1H), 4.25 (s, 1H), 4.12 (d, J = 9.3 Hz, 1H), 3.62-3.49 (m, 5H), 2.83 - 2.76 (m, 1H), 1.99-1.92 (m, 1H), 1.73-1.64 (m, 1H), 1.38 (s, 9H), 0.92 (s, 9H).

[0295] Step 3: methyl (3S)-3-{[(2S,4R)-1-[(2R)-2-{[(tert-butoxy)carbonyl]amino}-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}-3-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]propanoate. Bis(pinacolato)diboron (8.689 g, 34.21 mmol, 2 equiv.), potassium acetate (5.037 g, 51.32 mmol, 3 equiv.), methyl(3S)-3-(4-bromophenyl)-3-{[(2S,4R)-1-[(2R)-2-{[(tert-butoxy)carbonyl]amino}-3,3-dimethylbutanoyl]-4-hydroxypyrrolidine-2- [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) complex with dichloromethane (1.39 g, 1.71 mmol, 0.1 equiv.) was added to a mixture of 1,1'-bis(diphenylphosphino)ferrocene and dichloropalladium(II) (1.39 g, 1.71 mmol, 0.1 equiv.) stirred with argon for a while, then stirred further with argon and placed in a preheated oil bath at 95°C for 16 h. The reaction mixture was concentrated, then redissolved in DCM and purified by flash chromatography twice eluting with DCM / MeOH 98 / 2 to give the product. Further flash purification eluting with hexane / EtOAc-0 =>80% afforded 8 g of the desired product, methyl (3S)-3-{[(2S,4R)-1-[(2R)-2-{[(tert-butoxy)carbonyl]amino}-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}-3-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]propanoate (71% yield) as a light brown foam. ESI(+) [M+H] + =632.0; 1H NMR (300 MHz, DMSO-d6) δ 8.49 (d, J = 8.1 Hz, 1H), 7.65 - 7.57 (m, 2H), 7.30 (d, J = 8.0 Hz, 2H), 6.44 (d, J = 9.2 Hz, 1H), 5.22 - 5.05 (m, 2H), 4.43 - 4.34 (m, 1H), 4.25 (s, 1H), 4.13 (d, J = 9.4 Hz, 1H), 3.55 (s, 5H), 2.88 - 2.70 (m, 1H), 1.98 - 1.90 (m, 1H), 1.68 (ddd, J = 12.8, 8.2, 4.7 Hz, 1H), 1.38 (s, 9H), 1.28 (s, 12H), 0.93 (s, 9H).

[0296] Step 4: methyl (3S)-3-{[(2S,4R)-1-[(2R)-2-{[(tert-butoxy)carbonyl]amino}-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}-3-[4-(4-methyl-1,3-thiazol-5-yl)phenyl]propanoate. 5-Bromo-4-methylthiazole (3.383 g, 19.0 mmol, 1.5 equiv.), [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (complex with dichloromethane) (1.034 g, 1.266 mmol, 0.1 equiv.), potassium carbonate (5.02 g, 36.35 mmol, 2.87 equiv.), methyl(3S)-3-{[(2S,4R) The reaction mixture of -1-[(2R)-2-{[(tert-butoxy)carbonyl]amino}-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}-3-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]propanoate (8.0 g, 12.667 mmol, 1.0 equiv.) was stirred under argon for a while and then placed in a preheated oil bath at 100° C. and stirred for 16 hours. The reaction mixture was then filtered through a Celite pad, and the filtrate was concentrated and purified by flash chromatography eluting with DCM / MeOH (MeOH 10-30%) to afford 4.2 g of the desired product, methyl (3S)-3-{[(2S,4R)-1-[(2R)-2-{[(tert-butoxy)carbonyl]amino}-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}-3-[4-(4-methyl-1,3-thiazol-5-yl)phenyl]propanoate (51% yield) as a light brown solid. ESI(+) [M+H] + =589.3; 1H NMR (300 MHz, DMSO-d6) δ 8.99 (s, 1H), 8.55 (d, J = 7.9 Hz, 1H), 7.49 - 7.34 (m, 4H), 6.45 (d, J = 9.2 Hz, 1H), 5.15-5.08(m, 2H), 4.40 (t, J = 8.1 Hz, 1H), 4.27 (s, 1H), 4.14 (d, J = 9.3 Hz, 1H), 3.62 - 3.54 (m, 2H), 2.75 - 2.58 (m, 2H), 2.45 (s, 3H), 2.00 (d, J = 3.7Hz, 1H), 1.75 (s, 1H), 1.39 (s, 9H), 0.93 (s, 9H).

[0297] Step 5: Methyl (3S)-3-{[(2S,4R)-1-[(2R)-2-amino-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}-3-[4-(4-methyl-1,3-thiazol-5-yl)phenyl]propanoate hydrochloride. To a solution of methyl (3S)-3-{[(2S,4R)-1-[(2R)-2-{[(tert-butoxy)carbonyl]amino}-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}-3-[4-(4-methyl-1,3-thiazol-5-yl)phenyl]propanoate (4.9 g, 8.1 mmol, 1.0 equiv) in MeOH (68 mL, 0.3 M) was slowly added chilled 3 M HCl in MeOH (43.5 mL, 0.15 M) at 0° C. The mixture was stirred at room temperature for 16 hours. The MeOH was then removed by evaporation in vacuo, and the resulting residue was triturated with EtO to give the desired product, methyl (3S)-3-{[(2S,4R)-1-[(2R)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}-3-[4-(4-methyl-1,3-thiazol-5-yl)phenyl]propanoate hydrochloride (70% yield), as a foam-like white solid. ESI(+) [M+H] + =503.3; 1H NMR (300 MHz, DMSO-d6) δ 9.06 (s, 1H), 8.74 (d, J = 8.1 Hz, 1H), 8.10 (s, 4H), 7.43 (q, J = 8.4 Hz, 4H), 5.19 (d, J = 7.6 Hz, 1H), 4.51 (d, J = 8.4 Hz, 1H), 4.30 (s, 1H), 3.89 (d, J = 5.3 Hz, 1H), 3.73 (d, J = 11.0 Hz, 1H), 3.61 - 3.47 (m, 5H), 2.87-2.82 (m, 2H), 2.46 (s, 3H), 2.13 - 2.00 (m, 1H), 1.77-1.66 (m Hz, 1H), 1.02 (s, 9H). Step 6: Methyl (3S)-3-{[(2S,4R)-1-[(2R)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}-3-[4-(4-methyl-1,3-thiazol-5-yl)phenyl]propanoate

[0298] 1. To a mixture of 1-fluorocyclopropanecarboxylic acid (0.983 g, 9.45 mmol, 1.04 equiv) and DIPEA (2.4 mL, 1.5 equiv) in DMF (0.17 M) was added HATU (3.6 g, 9.5 mmol, 1.04 equiv) dissolved in DMF (0.15 M) slowly at 0° C. The reaction was stirred at room temperature for 30 min.

[0299] 2. To a solution of methyl (3S)-3-{[(2S,4R)-1-[(2R)-2-amino-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}-3-[4-(4-methyl-1,3-thiazol-5-yl)phenyl]propanoate (4.9 g, 9.2 mmol, 1.0 equivalent) in DMF (55 mL, 0.16 M) was added DIPEA (8.4 mL, 5 equivalents) at −40° C. and stirred at −40° C. for 5 minutes.

[0300] 3. Reactant 1 was slowly added to Reactant 2 at -40° C. The mixture was stirred at room temperature for 16 hours.

[0301] The reaction mixture was diluted with water and then extracted with DCM. The organic layer was washed with brine and dried under Na2SO4. The resulting crude was purified by flash chromatography eluting with DCM / MeOH-9 / 1 to give the product (3S)-3-{[(2S,4R)-1-[(2R)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}-3-[4-(4-methyl-1,3-thiazol-5-yl)phenyl]propanoic acid (47% yield) as a pale yellow solid. ESI(+) [M+H] + =589.35

[0308] 1 H NMR (300 MHz, DMSO-d6) δ 8.99 (s, 1H), 8.59 (d, J = 8.1 Hz, 1H), 7.44 (t, J = 7.5 Hz, 4H), 7.28 (dd, J = 9.2, 2.9 Hz, 1H), 5.25 - 5.11 (m, 2H), 4.57 (d, J = 9.2 Hz, 1H), 4.43 (t, J = 8.3 Hz, 1H), 4.27 (s, 1H), 3.63-3.52 (m, 5H), 2.86-2.81 (m, 1H), 2.46 (s, 3H), 2.08-2.00 (m, 1H), 1.79-1.68 (m, 1H), 1.42 - 1.29 (m, 2H), 1.24 - 1.18 (m, 2H), 0.96 (d, J = 6.4 Hz, 9H).

[0302] Step 7: (3S)-3-{[(2S,4R)-1-[(2R)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}-3-[4-(4-methyl-1,3-thiazol-5-yl)phenyl]propanoic acid. (3S)-3-{[(2S,4R)-1-[(2R)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}-3-[4-(4-methyl-1,3-thiazol-5-yl)phenyl]propanoic acid (2.8 g, 4.756 mmol, 1.0 equiv.) and lithium hydroxide monohydrate (0.409 g, 9.518 mmol, 2 equiv.) were dissolved in a mixture of tetrahydrofuran (2.8 ml, 1.7 M) and water (10.12 ml, 0.47 M) and stirred at room temperature for 2 hours. The THF was then removed under vacuum, and the resulting aqueous residue was neutralized to pH 4 with KHSO4, and the solid that formed was filtered to give the product (3S)-3-{[(2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}-3-[4-(4-methyl-1,3-thiazol-5-yl)phenyl]propanoic acid (86% yield) as a white-off solid. LCMS (254 nm): RT = 2.787 min, 93.13% purity. ESI(+) [M+H] + =575.24. 1H NMR (300 MHz, DMSO-d6) δ 8.99 (s, 1H), 8.55 (d, J = 7.6 Hz, 1H), 7.47 - 7.37 (m, 4H), 7.28 (dd, J = 9.2, 3.0 Hz, 1H), 5.17-5.09 (m, 2H), 4.57 (d, J = 9.2 Hz, 1H), 4.43 (t, J = 8.3 Hz, 1H), 4.27 (s, 1H), 3.59 (dd, J = 12.0, 8.3 Hz, 2H), 2.86 - 2.62 (m, 2H), 2.46 (s, 3H), 2.04 (t, J = 10.6 Hz, 1H), 1.73 (ddd, J = 13.1, 8.9, 4.5 Hz, 1H), 1.36 (ddd, J = 18.2, 5.7, 3.1 Hz, 2H), 1.25 - 1.16 (m, 2H), 0.96 (s, 9H). HVB15: 2-[2-({[(2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}methyl)-5-(4-methyl-1,3-thiazol-5-yl)phenoxy]acetic acid [ka]

[0303] Prepared similarly to HVB4, except that tert-butyl bromoacetate was used instead of tert-butyl 6-bromohexanoate. LCMS: C 28 H 35 FN4O7S Theoretical value: 590.22, Measured value: m / z = 591.3 [M+H] + . HVB16: (S)-3-((2S,4R)-1-((R)-2-(1-fluorocyclopropane-1-carboxamido)-3,3-dimethylbutanoyl)-4-hydroxypyrrolidine-2-carboxamido)-3-phenylpropanoic acid [ka]

[0304] Step 1: Methyl (3S)-3-{[(2S,4R)-1-[(2R)-2-amino-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}-3-(4-bromophenyl)propanoate hydrochloride. To a solution of methyl (3S)-3-(4-bromophenyl)-3-{[(2S,4R)-1-[(2R)-2-{[(tert-butoxy)carbonyl]amino}-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}propanoate (1.5 g, 2.566 mmol, 1.0 equiv) in MeOH (21 mL, 0.3 M) was slowly added a 3 M HCl solution in methanol (160 mL, 0.15 M) cooled to 0 °C. The mixture was stirred at room temperature for 64 hours (over the weekend). The MeOH was then removed and the resulting residue was triturated with EtO to give the product, methyl (3S)-3-{[(2S,4R)-1-[(2S)-2-amino-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}-3-(4-bromophenyl)propanoate hydrochloride (1.32 g, 2.534 mmol, 94%) as a pile yellow solid. ESI(-)[MH] - =482; 1 H NMR (300 MHz, DMSO-d6) 8.72 (d, J = 8.0 Hz, 1H), 8.10 (s, 3H), 7.53 - 7.48 (m, 2H), 7.30 - 7.23 (m, 2H), 5.11 (d, J = 7.7 Hz, 1H), 4.47 (t, J = 8.4 Hz, 1H), 4.28 (s, 1H), 3.88 (d, J = 5.1 Hz, 2H), 3.71 (d, J = 11.0 Hz, 1H), 3.48 (dd, J = 11.0, 3.8 Hz, 1H), 3.17 (s, 3H), 2.88 - 2.71 (m, 2H), 2.10 - 1.99 (m, 1H), 1.66 (s, 1H), 1.02 (s, 9H). Step 2: Methyl (3S)-3-(4-bromophenyl)-3-{[(2S,4R)-1-[(2R)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}propanoate

[0305] 1. To 1-fluorocyclopropanecarboxylic acid (0.274 g, 2.63 mmol, 1.04 equiv) in 5 mL of DMF (0.5 M) was added DIPEA (0.663 mL, 1.5 equiv) at 0° C. Then, HATU (1 g, 2.635 mmol, 1.04 equiv) was dissolved in 5 mL of DMF and added slowly to the above mixture at 0° C. The reaction was stirred at room temperature for 30 min.

[0306] 2. To a solution of methyl (3S)-3-{[(2S,4R)-1-[(2S)-2-amino-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamide}-3-(4-bromophenyl)propanoate hydrochloride (1.320 g, 2.534 mmol, 1.0 equivalent) in DMF (5 mL, 0.5 M) was added DIPEA (2.2 mL, 5 equivalents) at −40° C. and stirred at −40° C. for 5 minutes.

[0307] 3. Reactant 1 was slowly added to Reactant 2 at -40° C. The mixture was stirred at room temperature for 1 hour.

[0308] The reaction mixture was then diluted with water and extracted with DCM. The organic layer was washed with brine and dried under Na2SO4 to give the crude product, which was purified by FC eluting with DCM / MeOH-9 / 1 to give the desired product, methyl (3S)-3-(4-bromophenyl)-3-{[(2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}propanoate (1.117 g, 1.958 mmol, 73%). ESI(+) [M+H] + =570.2

[0316] 1 H NMR (300 MHz, DMSO-d6) δ 8.57 (d, J = 8.0 Hz, 1H), 7.55 - 7.46 (m, 2H), 7.31 - 7.23 (m, 3H), 5.17 - 5.09 (m, 2H), 4.57 (d, J = 9.1 Hz, 1H), 4.40 (t, J = 8.3 Hz, 1H), 4.25 (s, 1H), 3.56 (s, 4H), 3.20 - 3.03 (m, 1H), 2.84 - 2.70 (m, 2H), 2.05 - 1.92 (m, 1H), 1.69 (td, J = 8.6, 4.4 Hz, 1H), 1.36 (dd, J = 18.5, 3.5 Hz, 1H), 0.95 (d, J = 7.0 Hz, 9H).

[0309] Step 3: Methyl (3S)-3-{[(2S,4R)-1-[(2R)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}-3-phenylpropanoate. Methyl (3S)-3-{[(2S,4R)-1-[(2R)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}-3-phenylpropanoate) (0.834 g, 1.46 mmol, 1 equiv.) dissolved in i-PrOH (0.5 M) was degassed and charged with Pd(OAc) (0.4 equiv.) and stirred overnight under H (1 atm, balloon). The conversion was monitored by LCMS, NMR, and TLC. After complete consumption of the starting material, the reaction mixture was filtered through a Celite pad and concentrated under reduced pressure to give the desired product, methyl (3S)-3-{[(2S,4R)-1-[(2R)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}-3-phenylpropanoate (0.6 g, 1.22 mmol, 87% yield). ESI(-)[MH] - =490.30;ESI(+)[M+H] + =492.25;1 H NMR (300 MHz, DMSO-d6) δ 8.53 (d, J = 8.2 Hz, 1H), 7.35 - 7.20 (m, 6H), 5.23 - 5.08 (m, 2H), 4.61 - 4.53 (d, J = 9.35 Hz, 1H), 4.42 (t, J = 8.2 Hz, 1H), 4.26 (s, 1H), 3.60 (m, 3.62-3.53 Hz, 5H), 2.88 - 2.70 (m, 2H), 2.05 - 1.96 (m, 1H), 1.74-1.65 (m, 1H), 1.42 - 1.31 (m, 2H), 1.25 - 1.17 (m, 3H), 0.96 (s, 9H).

[0310] Step 4: (S)-3-((2S,4R)-1-(R)-2-(1-fluorocyclopropane-1-carboxamido)-3,3-dimethylbutanoyl)-4-hydroxypyrrolidine-2-carboxamido)-3-phenylpropanoic acid. Methyl (3S)-3-{[(2S,4R)-1-[(2R)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}-3-phenylpropanoate (0.6 g, 1.22 mmol, 1 equivalent) dissolved in a mixture of THF / HO-5 / 1 (0.5 M) was added lithium hydroxide monohydrate (0.042 g, 2.44 mmol, 2 equivalents) and stirred at room temperature for 16 hours. The reaction was monitored by TLC and LCMS. The THF was evaporated and the remaining aqueous layer was neutralized with NaHSO4 (2 equiv.), the mixture was concentrated and the resulting dry residue was triturated with DCM to give the desired product, methyl (3S)-3-{[(2S,4R)-1-[(2R)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxypyrrolidin-2-yl]formamido}-3-phenylpropanoate (0.350 g, 0.732 mmol, 81% yield): LCMS: 254 nm, RT = 2.09 min, 87.76%, ESI (-) [MH] - =475.98; 1H NMR (300 MHz, DMSO-d6) δ 12.24 (s, 1H), 8.46 (d, J = 8.1 Hz, 1H), 7.33 - 7.20 (m, 6H), 5.16 - 5.03 (m, 2H), 4.57 (d, J = 9.1 Hz, 1H), 4.42 (t, J = 8.3 Hz, 1H), 4.25 (s, 1H), 3.64 - 3.49 (m, 2H), 2.77 (dd, J = 15.7, 6.6 Hz, 1H), 2.64 (dd, J = 15.6, 8.2 Hz, 1H), 2.06 - 1.95 (m, 1H), 1.70 (ddd, J = 12.8, 8.7, 4.4 Hz, 1H), 1.42 - 1.31 (m, 2H), 1.24 - 1.17 (m, 3H), 0.96 (s, 9H). HVB17 (2S,4S)-1-((S)-2-amino-3,3-dimethylbutanoyl)-4-hydroxy-N-(4-(4-methylthiazol-5-yl)benzyl)pyrrolidine-2-carboxamide [ka]

[0311] Step 1: Synthesis of tert-butyl N-[(4-bromophenyl)methyl]carbamate. To a solution of (4-bromophenyl)methanamine (22.8 g, 122.55 mmol, 15.51 mL, 1 equiv.) and TEA (18.60 g, 183.82 mmol, 25.59 mL, 1.5 equiv.) in DCM (150 mL) was added tert-butoxycarbonyl tert-butyl carbonate (29.42 g, 134.80 mmol, 30.97 mL, 1.1 equiv.). The mixture was stirred at 25 °C for 2 hours. TLC (petroleum ether / ethyl acetate = 10:1) showed that the substance (4-bromophenyl)methanamine had been consumed, and a major new spot was detected. The mixture was poured into water (150 mL), the organic layer was separated, washed with aqueous 1 N HCl (150 mL) and brine (100 mL), then the organic layer was dried over anhydrous NaSO, filtered, and the filtrate was concentrated. The residue was purified by trituration in petroleum ether (120 mL), collected by filtration, and the filter cake was dried under vacuum to give tert-butyl N-[(4-bromophenyl)methyl]carbamate (26.3 g, 91.91 mmol, 75% yield) as a white solid.

[0312] Step 2: Synthesis of tert-butyl N-[[4-(4-methylthiazol-5-yl)phenyl]methyl]carbamate. To a stirred solution of tert-butyl N-[(4-bromophenyl)methyl]carbamate (26.3 g, 91.91 mmol, 1 equiv.) in DMA (150 mL) under an atmosphere of N was added 4-methylthiazole (18.23 g, 183.81 mmol, 16.72 mL, 2 equiv.), KOAc (18.04 g, 183.81 mmol, 2 equiv.), and Pd(OAc) (1.03 g, 4.60 mmol, 0.05 equiv.). The resulting mixture was stirred at 120 °C for 16 h. LCMS showed that a major peak with the desired MS was detected. TLC (petroleum ether / ethyl acetate=5:1) showed that the material, tert-butyl N-[(4-bromophenyl)methyl]carbamate, had been consumed and a major new spot was detected. The mixture was poured into water (200 mL) and the aqueous mixture was diluted with ethyl acetate (150 mL).* The mixture was extracted with 2), and the combined organic layers were washed with brine (100 mL), dried over anhydrous NaSO, and concentrated. The residue was triturated with petroleum ether:ethyl acetate = 10:1 (80 mL) to give tert-butyl N-[[4-(4-methylthiazol-5-yl)phenyl]methyl]carbamate (16.8 g, 55.19 mmol, 60.05% yield) as a yellow solid. MS [M+H] + =305.0. 1 H NMR (400MHz, CDCl3) δ 8.70 (s, 1H), 7.46 - 7.41 (m, 2H), 7.40 - 7.34 (m, 2H), 4.98 - 4.87 (m, 1H), 4.39 (d, J = 5.9 Hz, 2H), 2.55 (s, 3H), 1.50 (s, 9H).

[0313] Step 3: Synthesis of [4-(4-methylthiazol-5-yl)phenyl]methanamine. A mixture of tert-butyl N-[[4-(4-methylthiazol-5-yl)phenyl]methyl]carbamate (16.8 g, 55.19 mmol, 1 eq) in HCl / dioxane (4 M, 50 mL, 3.62 eq) was stirred at 25 °C for 1 hour. LCMS showed that a major peak with the desired mass was detected. Evaporation of the solvent gave [4-(4-methylthiazol-5-yl)phenyl]methanamine (13.3 g, crude, HCl) as a yellow solid, which was used directly in the next step without any purification. MS [M+H] + =205.1.

[0314] Step 4: Synthesis of tert-butyl (2S,4S)-4-hydroxy-2-[[4-(4-methylthiazol-5-yl)phenyl]methylcarbamoyl]pyrrolidine-1-carboxylate. To a mixture of (2S,4S)-1-tert-butoxycarbonyl-4-hydroxy-pyrrolidine-2-carboxylic acid (12.77 g, 55.24 mmol, 1.0 equiv) and DIPEA (14.28 g, 110.49 mmol, 19.24 mL, 2 equiv) in DMF (120 mL) was added HATU (23.11 g, 60.77 mmol, 1.1 equiv). The mixture was stirred at 25° C. for 30 minutes, then [4-(4-methylthiazol-5-yl)phenyl]methanamine (13.3 g, 55.24 mmol, 1 equiv., HCl) was added and the resulting mixture was stirred at 25° C. for 1.5 hours. LCMS showed that the material [4-(4-methylthiazol-5-yl)phenyl]methanamine was consumed and the desired mass was detected. The mixture was poured into water (100 mL) and the resulting aqueous solution was dissolved in ethyl acetate (100 mL). * The combined organic layer was dried over anhydrous NaSO and concentrated. The residue was purified by chromatography (silica gel, eluting with DCM:MeOH = 100:1, 50:1) to give tert-butyl (2S,4S)-4-hydroxy-2-[[4-(4-methylthiazol-5-yl)phenyl]methylcarbamoyl]pyrrolidine-1-carboxylate (17 g, 38.19 mmol, 69.13% yield, 93.8% purity) as a pale yellow oil. MS [M+H] + =418.3.

[0315] Step 5: Synthesis of (2S,4S)-4-hydroxy-N-[[4-(4-methylthiazol-5-yl)phenyl]methyl]pyrrolidine-2-carboxamide. A mixture of tert-butyl (2S,4S)-4-hydroxy-2-[[4-(4-methylthiazol-5-yl)phenyl]methylcarbamoyl]pyrrolidine-1-carboxylate (5 g, 11.23 mmol, 1 equivalent) in HCl / dioxane (4 M, 50 mL, 17.80 equivalents) was stirred at 25° C. for 1 hour. LCMS showed that the substance tert-butyl (2S,4S)-4-hydroxy-2-[[4-(4-methylthiazol-5-yl)phenyl]methylcarbamoyl]pyrrolidine-1-carboxylate was consumed, and a major peak having the desired mass was detected. Evaporation of the solvent gave (2S,4S)-4-hydroxy-N-[[4-(4-methylthiazol-5-yl)phenyl]methyl]pyrrolidine-2-carboxamide (4 g, crude, HCl) as a pale yellow solid, which was used directly in the next step without any purification. MS (M+H) + =318.1.

[0316] Step 6: Synthesis of tert-butyl N-[(1S)-1-[(2S,4S)-4-hydroxy-2-[[4-(4-methylthiazol-5-yl)phenyl]methylcarbamoyl]pyrrolidine-1-carbonyl]-2,2-dimethyl-propyl]carbamate. To a solution of (2S,4S)-4-hydroxy-N-[[4-(4-methylthiazol-5-yl)phenyl]methyl]pyrrolidine-2-carboxamide (4 g, 11.30 mmol, 1 equiv, HCl) and (2S)-2-(tert-butoxycarbonylamino)-3,3-dimethyl-butanoic acid (2.61 g, 11.30 mmol, 1 equiv) in DMF (30 mL) was added HATU (4.73 g, 12.43 mmol, 1.1 equiv) and DIPEA (2.92 g, 22.61 mmol, 3.94 mL, 2 equiv) at 0° C., and the mixture was then stirred at 25° C. for 2 h. LCMS showed that the material (2S,4S)-4-hydroxy-N-[[4-(4-methylthiazol-5-yl)phenyl]methyl]pyrrolidine-2-carboxamide had been consumed and a major peak with the desired mass was detected. The mixture was poured into water (100 mL) and the resulting water was diluted with ethyl acetate (100 mL). * The resulting mixture was extracted with 2). The combined organic layers were dried over anhydrous Na2SO4 and concentrated. The residue was purified by reverse flash MPLC (FA) to give tert-butyl-N-[(1S)-1-[(2S,4S)-4-hydroxy-2-[[4-(4-methylthiazol-5-yl)phenyl]methylcarbamoyl]pyrrolidine-1-carbonyl]-2,2-dimethyl-propyl]carbamate (1.65 g, 3.01 mmol, 26.60% yield, 96.7% purity) as a pale yellow gum. MS [M+H] + =531.2.

[0317] Step 7: Synthesis of (2S,4S)-1-[(2S)-2-amino-3,3-dimethyl-butanoyl]-4-hydroxy-N-[[4-(4-methylthiazol-5-yl)phenyl]methyl]pyrrolidine-2-carboxamide. To a solution of tert-butyl N-[(1S)-1-[(2S,4S)-4-hydroxy-2-[[4-(4-methylthiazol-5-yl)phenyl]methylcarbamoyl]pyrrolidine-1-carbonyl]-2,2-dimethyl-propyl]carbamate (3.35 g, 6.31 mmol, 1 equiv.) in dioxane (10 mL) was added HCl / dioxane (4 M, 20 mL, 12.67 equiv.). The mixture was stirred at 25° C. for 1 hour. LCMS showed that a major peak with the desired mass was detected. The solvent was evaporated. The residue was triturated in petroleum ether / ethyl acetate (10:1, 80 mL) and collected by filtration to give (2S,4S)-1-[(2S)-2-amino-3,3-dimethyl-butanoyl]-4-hydroxy-N-[[4-(4-methylthiazol-5-yl)phenyl]methyl]pyrrolidine-2-carboxamide (2.77 g, 5.63 mmol, 89.20% yield, 94.8% purity, HCl) as a white powder. MS [M+H] + =431.3. 1 H NMR (400MHz, CD3OD) δ 9.78 (s, 1H), 7.63 - 7.48 (m, 4H), 4.65 - 4.59 (m, 1H), 4.57 - 4.54 (m, 1H), 4.06 (s, 1H), 4.00 - 3.94 (m, 1H), 3.67 - 3.63 (m, 1H), 3.62 (s, 2H), 2.60 (s, 3H), 2.57 - 2.49 (m, 1H), 1.99 (d, J = 13.4 Hz, 1H), 1.15 (s, 9H). HVB18: (2S,4R)-1-[(2S)-2-amino-3,3-dimethylbutanoyl]-N-[(1S)-1-(4-bromophenyl)ethyl]-4-hydroxypyrrolidine-2-carboxamide [ka]

[0318] The same protocol was followed as for the synthesis of (2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxy-N-{[2-hydroxy-4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}pyrrolidine-2-carboxamide (Scheme B4), except that (S)-1-(4-bromophenyl)ethan-1-amine was used instead of 2-(aminomethyl)-5-(4-methyl-1,3-thiazol-5-yl)phenol. LCMS: C 19 H 28 BrN3O3 theoretical value: 425.13, measured value: m / z = 426.67 [M+H] + . HVB19: (2S,4R)-1-[(2S)-2-amino-3,3-dimethylbutanoyl]-4-hydroxy-N-[(1S)-1-phenylethyl]pyrrolidine-2-carboxamide [ka]

[0319] The title compound was obtained by following the same protocol as for the synthesis of (2S,4R)-1-[(2S)-2-[(1-fluorocyclopropyl)formamido]-3,3-dimethylbutanoyl]-4-hydroxy-N-{[2-hydroxy-4-(4-methyl-1,3-thiazol-5-yl)phenyl]methyl}pyrrolidine-2-carboxamide (Scheme B4), except that (S)-1-phenylethan-1-amine was used instead of 2-(aminomethyl)-5-(4-methyl-1,3-thiazol-5-yl)phenol. LCMS: C 19 H 29 N3O3 theoretical value: 347.22, measured value: m / z = 348.13 [M+H] + . HVB20: (3R)-3-((2R,4S)-4-hydroxy-1-(3-methyl-2-(3-methylisoxazol-5-yl)butanoyl)pyrrolidine-2-carboxamido)-3-(4-(4-methylthiazol-5-yl)phenyl)propanoic acid [ka]

[0320] Step 1: Methyl (3S)-3-amino-3-(4-bromophenyl)propanoate. To a solution of (3S)-3-(4-bromophenyl)-3-{[(tert-butoxy)carbonyl]amino}propanoic acid (8.0 g, 0.023 mmol, 1.0 equiv.) in methanol (100 mL, 0.01 M) was slowly added a cooled solution of HCl (3 M in MeOH, 160 mL, 0.01 M) at 0 °C. The mixture was stirred at room temperature for 16 h. The crude reaction was concentrated in vacuo at 30 °C, and then a 3 M solution of HCl in EtO (40 mL) was added followed by concentration in vacuo to afford methyl (3S)-3-amino-3-(4-bromophenyl)propanoate as a foamy white solid. The product was isolated as the HCl salt and carried on to the next step without further purification (5.71 g, 95% yield). ESI(+)[M+H] + =258.00; 1 H NMR (300 MHz, Methanol-d4), δ: 7.63 (d, J = 8.2 Hz, 2H), 7.40 (d, J = 8.2 Hz, 2H), 4.73 (t, J = 7.1 Hz, 1H), 3.70 (s, 3H), 3.19 - 2.97 (m, 2H).

[0321] Step 2: tert-Butyl (2S,4R)-2-{[(1S)-1-(4-bromophenyl)-3-methoxy-3-oxopropyl]carbamoyl}-4-hydroxypyrrolidine-1-carboxylate. To a solution of (2S,4R)-1-[(tert-butoxy)carbonyl]-4-hydroxypyrrolidine-2-carboxylic acid (5.71 g, 24.7 mmol, 1.15 equiv.) in DMF (45 mL, 0.5 M) was added DIPEA (6 mL, 1.5 equiv.) at 0 °C. Next, to the previous solution was slowly added a solution of HATU (8.53 g, 22.5 mmol, 1.04 equiv.) in DMF (45 mL, 0.5 M) at 0 °C. The reaction mixture was stirred at room temperature for 0.5 h and then slowly added at -30 °C to a cooled DMF (35 mL, 0.6 M) solution of methyl (3S)-3-amino-3-(4-bromophenyl)propanoate (6.7 g, 21.5 mmol, 1 equiv.) pretreated with DIPEA (20 mL, 5 equiv.). The mixture was stirred at -30 °C and allowed to slowly warm to room temperature over 2 h (monitored by TLC, UPLC, and NMR). The crude reaction mixture was then poured onto crushed ice and extracted with DCM (6 × 500 mL). The organic layer was dried over Na SO , concentrated in vacuo, and purified by flash column chromatography (eluent DCM / MeOH 9:1) to give the desired compound as a foamy white solid (10.54 g, quantitative yield). ESI (+) [M+H] + =471.10; 1 H NMR (300 MHz, DMSO-d6) Methanol-d4) δ 7.47 (t, J = 7.9 Hz, 2H), 7.36 - 7.20 (m, 2H), 5.32 (t, J = 7.4 Hz, 1H), 4.29 (dd, J = 15.4, 6.9 Hz, 2H), 3.62 (s, 3H), 3.60 - 3.40 (m, 1H), 3.03 - 2.73 (m, 2H), 2.34 - 2.08 (m, 1H), 2.03 - 1.76 (m, 1H), 1.47 (s, 3H), 1.40 - 1.29 (s, 6H). No Boc protons observed.

[0322] Step 3: Methyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1,3-thiazole. A mixture of 5-bromo-4-methyl-1,3-thiazole (7.5 g, 42.1 mmol, 1 equiv.), KOAc (12.4 g, 126.4 mmol, 3.4 equiv.), 4,4,5,5-tetramethyl-2-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1,3,2-dioxaborolane (21.4 g, 1.85 mmol, 2 equiv.) and Pd(PPh3)4 (10 g, 20 mol%) was dissolved in dioxane (375 mL, 0.1 M), purged with argon for 10 min, and stirred at 95 °C for 16 h. The mixture was then cooled to room temperature, filtered through a pad of Celite, concentrated in vacuo, and purified by short manual column chromatography (eluent hexane / EtOAc 1:1) to give the title product as an off-white solid (10.25 g, 52% yield, contaminated with 50% by weight of the pinacol derivative). 1 H NMR (300 MHz, Chloroform-d), δ: 8.92 (s, 1H), 2.70 (s, 3H), 1.34 (s, 12H).

[0323] Step 4: (3S)-3-{[(2S,4R)-1-[(tert-butoxy)carbonyl]-4-hydroxypyrrolidin-2-yl]formami-do}-3-[4-(4-methyl-1,3-thiazol-5-yl)phenyl]propanoic acid methyl ester. A mixture of tert-butyl (2S,4R)-2-{[(1S)-1-(4-bromophenyl)-3-methoxy-3-oxopropyl]carbamoyl}-4-hydroxypyrrolidine-1-carboxylate (9 g, 19.09 mmol, 1 equiv.), 4-methyl-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1,3-thiazole (9.91 g, 21 mmol, 1.2 equiv.), KCO (13.2 g, 95.5 mmol, 5 equiv.), Pd(dppf)Cl. DCM (1.6 g, 10 mol%) in dioxane / HO (5:1, 380 mL, 0.05 M) was purged with argon for 20 min and stirred at 110 °C for 2 h (Suzuki coupling completion). The mixture was then cooled to room temperature and filtered through a pad of Celite. The filtrate was concentrated in vacuo and purified by flash column chromatography (eluent DCM / MeOH / AcOH 8:2:0.2% to 6:4:0.2%). The desired product was concentrated in vacuo, dissolved in DCM / MeOH / AcOH 9:1:0.1%, and filtered to remove the final silica gel. The filtrate was concentrated in vacuo and then precipitated in diethyl ether to give the desired product as a gray solid (6.6 g, 76% yield). ESI(+)[M+H] + =476.07; 1 H NMR (300 MHz, Methanol-d4), δ: 8.88 (s, 1H), 7.47 (m, 4H), 5.54 - 5.28 (m, 1H), 4.33 (d, J = 9.9 Hz, 2H), 3.68 - 3.40 (m, 2H), 3.60 (s, 3H), 2.88 (m, 2H), 2.48 (s, 3H), 2.31 - 2.14 (m, 1H), 1.99 (s, 1H), 1.48 (s, 3H), 1.33 (s, 6H).

[0324] Step 5: Methyl (3S)-3-{[(2S,4R)-4-hydroxypyrrolidin-2-yl]formamido}-3-[4-(4-methyl-1,3-thiazol-5-yl)phenyl]propanoate. A mixture of (3S)-3-{[(2S,4R)-1-[(tert-butoxy)carbonyl]-4-hydroxypyrrolidin-2-yl]formamido}-3-[4-(4-methyl-1,3-thiazol-5-yl)phenyl]propanoic acid methyl ester (0.3 g, 0.61 mmol, 1 equivalent) and 2N HCl in methanol (10 equivalents) was stirred at ambient conditions for 2 hours (reaction monitored by UPLC and NMR). The solvent was removed in vacuo and the resulting solid was triturated with dry diethyl ether to give the desired salt product as a thick brown oil (0.22 g, 83% yield). ESI(+)[M+H] + =390.45; 1 H NMR (300 MHz, DMSO-d6) δ: 9.89 (s, 1H), 9.32 (d, J = 7.9 Hz, 1H), 9.03 (s, 1H), 8.65 (s, 1H), 7.51 - 7.39 (m, 4H), 4.33 (s, 2H), 3.61 (s, 3H), 3.51 (s, 1H), 3.41 (s, 2H), 3.07 (d, J = 4.7 Hz, 1H), 2.88 (d, J = 7.5 Hz, 2H), 2.33 (s, 1H), 1.78 (m, 1H).

[0325] Step 6: Methyl 2-(3-methyl-1,2-oxazol-5-yl)acetate. To a solution of 3-methyl-5-isoxazoleacetic acid (0.8 g, 5.67 mmol, 1 equiv.) in MeOH (10 mL, 0.55 M) was added thionyl chloride (1.5 equiv.) dropwise at 0° C., and the resulting mixture was stirred at 50° C. for 4 h. UPLC monitoring was used. The reaction mixture was then poured into saturated ammonium chloride, extracted with EtOAc, washed with saturated NaHCO3, dried, and concentrated in vacuo to give the desired product as a brown oil (0.78 g, 89% yield). 1H NMR (300 MHz, Chloroform-d), δ: 6.11 (s, 1H), 3.80 (s, 2H), 2.76 (s, 3H), 2.30 (s, 3H).

[0326] Step 7: Methyl 3-methyl-2-(3-methyl-1,2-oxazol-5-yl)butanoate. A mixture of methyl 2-(3-methyl-1,2-oxazol-5-yl)acetate (0.14 g, 0.9 mmol, 1 equiv.), cesium carbonate (0.32 g, 0.99 mmol, 1.1 equiv.), and 2-iodopropane (0.16 g, 0.94 mmol, 1.05 equiv.) in DMSO (2.3 mL, 0.4 M) was stirred at 65-70 °C for 5-8 h (LCMS control was applied). After completion of the reaction, the reaction mixture was poured into dilute aqueous HCl, extracted twice with EtOAc, dried, and the solvent evaporated in vacuo. The crude product was purified by flash chromatography using ELSD (the product is not UV-sensitive) to give the desired product (0.12 g, 64% yield). 1 H NMR (300 MHz, DMSO-d6), δ: 6.30 (s, 1H), 3.76 (d, J = 8.6 Hz, 1H), 3.66 (s, 3H), 2.35 - 2.26 (m, 1H), 2.21 (s, 3H), 0.93 (d, J = 6.7 Hz, 3H), 0.83 (d, J = 6.7 Hz, 3H).

[0327] Step 8: 3-Methyl-2-(3-methyl-1,2-oxazol-5-yl)butanoic acid. To a solution of starting methyl 3-methyl-2-(3-methyl-1,2-oxazol-5-yl)butanoate (0.59 g, 2.99 mmol, 1 equiv.) in THF-water (3:1; 0.14 M) was added sodium hydroxide (0.18 g, 4.5 mmol, 1.5 equiv.), and the resulting mixture was stirred at room temperature until the reaction was complete (controlled by TLC). Next, the THF was evaporated under reduced pressure, and the remaining water was acidified to pH 4-3 with 1 N aqueous HCl. The resulting solution was extracted twice with EtOAc and dried. After evaporation of all volatiles, the desired compound was obtained as a white solid (0.5 g, 90% yield). 1 H NMR (300 MHz, DMSO-d6), δ: 12.84 (s, 1H), 6.27 (s, 1H), 3.58 (d, J = 8.7 Hz, 1H), 2.35 - 2.23 (m, 1H), 2.21 (s, 3H), 0.96 (d, J = 6.7 Hz, 3H), 0.82 (d, J = 6.7 Hz, 3H).

[0328] Step 9: (3S)-3-{[(2S,4R)-4-hydroxy-1-[3-methyl-2-(3-methyl-1,2-oxazol-5-yl)butanoyl]-pyrrolidin-2-yl]formamido}-3-[4-(4-methyl-1,3-thiazol-5-yl)phenyl]propanoic acid. To a solution of methyl (3S)-3-{[(2S,4R)-4-hydroxypyrrolidin-2-yl]formamido}-3-[4-(4-methyl-1,3-thiazol-5-yl)phenyl]propanoate (0.23 g, 0.56 mmol, 1 equiv.) and 3-methyl-2-(3-methyl-1,2-oxazol-5-yl)butanoic acid (0.11 g, 0.62 mmol, 1.1 equiv.) in DCM (6 mL, 0.1 M) was added DIPEA (0.22 mL, 1.7 mmol, 3.00 equiv.) and HATU (0.32 g, 0.84 mmol, 1.5 equiv.). The mixture was stirred overnight at 25 °C. UPLC control was used. The reaction mixture was quenched with water and extracted with ethyl acetate. The combined organic layers were washed with acidic water, brine, dried over Na2SO4 and concentrated to give the crude product, which was purified by flash chromatography as a viscous oil (0.28 g, 78% yield). ESI(+)[M+H] + =556.04; 1 H NMR (300 MHz, DMSO-d6), δ: 8.72 (s, 1H), 7.47-7.35 (br m, 4H), 6.10 (m, 1H), 5.35 (m, 1H), 4.60 (m, 2H), 3.72 (m, 4H), 3.60 (s, 3H), 2.77 (m, 2H), 2.50 (m, 4H), 2.25 (m, 4H), 2.06 (m, 1H), 1.07 (m, 3H), 0.89 (m, 3H).

[0329] Step 10: (3S)-3-{[(2S,4R)-4-hydroxy-1-[3-methyl-2-(3-methyl-1,2-oxazol-5-yl)butanoyl]-pyrrolidin-2-yl]formamido}-3-[4-(4-methyl-1,3-thiazol-5-yl)phenyl]propanoic acid. To a solution of starting (3S)-3-{[(2S,4R)-4-hydroxy-1-[3-methyl-2-(3-methyl-1,2-oxazol-5-yl)butanoyl]-pyrrolidin-2-yl]formamido}-3-[4-(4-methyl-1,3-thiazol-5-yl)phenyl]propanoic acid (0.28 g, 0.54 mmol, 1 equiv.) in methanol-water (3:1; 0.14 M) was added sodium hydroxide (0.03 g, 0.75 mmol, 1.5 equiv.), and the resulting mixture was stirred at ambient conditions until completion (controlled by UPLC). The organic solvent was then evaporated under reduced pressure, and the aqueous residue was acidified to pH 4–3 with 1N HCl. The resulting solution was purified by reverse-phase flash chromatography (5–29% acetonitrile in water). After solvent evaporation, the title compound was obtained as a white solid (0.1 g, 37% yield). LCMS: 254nm, RT=2.443min, 98.32% purity, ESI(+)[M+H] + =542.66; 1 H NMR (300 MHz, DMSO-d6), δ: 8.90 (s, 1H), 7.47 (m, 4H), 6.25 (d, J = 5.9 Hz, 1H), 5.38 (m, 1H), 4.62 - 4.37 (m, 2H), 3.94 - 3.41 (m, 4H), 3.10 - 2.78 (m, 2H), 2.50 (m, 4H), 2.25 (m, 4H), 1.98 (m, 1H), 1.07 (d, J = 7.6 Hz, 3H), 0.94 - 0.82 (m, 3H). C. General scheme for coupling IRAK4 binding and LHM building blocks

[0330] The L moiety typically has up to five linker segments (-L1-L2-L3-L4-L5-), one of which is formed by coupling an IRAK4 building block and an LHM block described herein via a bond formation (e.g., amide). The following general methods A-D illustrate the bond formations by which building blocks can be linked to provide compounds of Formula (I). General Method A (Amide Coupling): [ka] General Method B (Reductive Amination): [ka] General method C (replacement): [ka] General Method D (Amide Coupling, In-Situ BOC Deprotection)

[0331] General Method D is similar to General Method A, except that the amine terminal moiety (e.g., of an IRAK4 building block) can first be protected with BOC. Amide coupling can be performed in situ with BOC deprotection to form an amide bond with the carboxylic acid terminal moiety (e.g., of an LHM building block). See, for example, the synthesis of Example 50. definition

[0332] The following description sets forth example methods, parameters, etc. However, it should be recognized that such description is not intended as a limitation on the scope of the present disclosure, but is instead presented as a description of example embodiments.

[0333] A dash ("-") that is not between two letters or symbols is used to indicate a point of attachment for a substituent. For example, -C(O)NH2 is attached through the carbon atom. A dash at the front or end of a chemical group is for convenience, and a chemical group may be depicted with or without one or more dashes without losing its original meaning. A wavy line depicted across a line in a structure indicates the point of attachment of the group. Unless chemically or structurally necessary, no direction is indicated or implied by the order in which chemical groups are written or named.

[0334] Prefix “C” u~v " indicates that the following group has u to v carbon atoms. For example, "C 1~6 "Alkyl" indicates that the alkyl group has from 1 to 6 carbon atoms.

[0335] Reference herein to "about" a value or parameter includes (and describes) embodiments that are directed to the value or parameter itself. In certain embodiments, the term "about" includes ±10% of the stated amount. In other embodiments, the term "about" includes ±5% of the stated amount. In certain other embodiments, the term "about" includes ±1% of the stated amount. Similarly, the term "with respect to X" includes a description of "X." Furthermore, the singular forms "a" and "the" include plural references unless the context clearly dictates otherwise. Thus, for example, reference to a "compound" includes a plurality of such compounds, and reference to an "assay" includes reference to one or more assays and equivalents thereof known to those of skill in the art.

[0336] "Alkyl" refers to a branched saturated hydrocarbon chain containing no unsaturation. As used herein, alkyl refers to a group having 1 to 20 carbon atoms (i.e., C 1~20 alkyl), 1 to 12 carbon atoms (i.e., C 1~12 alkyl), 1 to 8 carbon atoms (i.e., C 1~8 alkyl), 1 to 6 carbon atoms (i.e., C 1~6 alkyl) or 1 to 4 carbon atoms (i.e., C1~4 alkyl). Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, iso-butyl, tert-butyl, pentyl, 2-pentyl, isopentyl, neopentyl, hexyl, 2-hexyl, 3-hexyl, and 3-methylpentyl. When an alkyl residue having a specific number of carbons is named by a chemical name or specified by a molecular formula, all positional isomers having that number of carbons can be contemplated; thus, for example, "butyl" includes n-butyl (i.e., -(CH2)3CH3), sec-butyl (i.e., -CH(CH3)CH2CH3), isobutyl (i.e., -CH2CH(CH3)2), and tert-butyl (i.e., -C(CH3)3); and "propyl" includes n-propyl (i.e., -(CH2)2CH3) and isopropyl (i.e., -CH(CH3)2).

[0337] "Alkylene" or "alkylene chain" refers to a divalent unbranched or branched hydrocarbon chain, e.g., methylene, ethylene, propylene, n-butylene, etc., which is free of unsaturation and has from 1 to 20 carbon atoms, or more typically from 1 to 12 carbon atoms, or from 1 to 8 carbon atoms, that connects a radical group to the rest of the molecule. The alkylene chain can be attached to the rest of the molecule and to the radical group through one carbon within the chain or through any two carbons within the chain.

[0338] "Alkenyl" refers to an alkyl group containing at least one carbon-carbon double bond and having 2 to 20 carbon atoms (i.e., C 2~20 alkenyl), or more typically, 2 to 12 carbon atoms (i.e., C 2~12 alkenyl), 2 to 8 carbon atoms (i.e., C 2~8 alkenyl), 2 to 6 carbon atoms (i.e., C 2~6 alkenyl) or 2 to 4 carbon atoms (i.e., C 2~4Examples of alkenyl groups include ethenyl, propenyl, and butadienyl (including 1,2-butadienyl and 1,3-butadienyl).

[0339] "Alkenylene" and "alkenylene chain" refer to a divalent unbranched or branched hydrocarbon chain, such as ethenylene, propenylene, n-butenylene, and the like, containing at least one double bond and having 2 to 20 carbon atoms, or more typically 2 to 12 carbon atoms, or 2 to 8 carbon atoms, linking the rest of the molecule to a radical group. The alkenylene chain is attached to the rest of the molecule through a single bond and to the radical group through a double bond or a single bond. The points of attachment of the alkenylene chain to the rest of the molecule and to the radical group can be through one carbon or any two carbons within the chain.

[0340] "Alkynyl" refers to an alkyl group containing at least one carbon-carbon triple bond and having 2 to 20 carbon atoms (i.e., C 2~20 alkynyl), or more typically, 2 to 12 carbon atoms (i.e., C 2~12 alkynyl), or more typically, 2 to 8 carbon atoms (i.e., C 2~8 alkynyl), 2 to 6 carbon atoms (i.e., C 2~6 alkynyl), or 2 to 4 carbon atoms (i.e., C 2~4 The term "alkynyl" also includes such groups having one triple bond and one double bond.

[0341] "Alkynylene" and "alkynylene chain" refer to a divalent unbranched or branched hydrocarbon chain containing at least one triple bond and having 2 to 20 carbon atoms, or more typically 2 to 12 carbon atoms, or 2 to 8 carbon atoms, linking the rest of the molecule to a radical group. The alkynylene chain is attached to the rest of the molecule through a single bond and to the radical group through a double bond or a single bond. The points of attachment of the alkynylene chain to the rest of the molecule and to the radical group can be through one carbon or any two carbons within the chain.

[0342] "Alkoxy" refers to the group "alkyl-O-." Examples of alkoxy groups include methoxy, ethoxy, n-propoxy, iso-propoxy, n-butoxy, tert-butoxy, sec-butoxy, n-pentoxy, n-hexoxy, and 1,2-dimethylbutoxy.

[0343] "Haloalkoxy" refers to an alkoxy group, as defined above, in which one or more hydrogen atoms are replaced by halogen.

[0344] "Alkylthio" refers to the group "alkyl-S-".

[0345] "Amino" means -NR y R y R refers to the group y is each independently selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, aryl, heterocyclyl, cycloalkyl, or heteroaryl, any of which is optionally substituted as defined herein.

[0346] "Aryl" refers to an aromatic carbocyclic group having a single ring (e.g., monocyclic) or multiple rings (e.g., bicyclic or tricyclic), including fused systems. Aryl, as used herein, refers to an aromatic carbocyclic group having 6 to 20 ring carbon atoms (i.e., C 6~20 aryl), 6 to 15 carbon ring atoms (i.e., C 6~15aryl) or 6 to 10 carbon ring atoms (i.e., C 6~10 aryl). Examples of aryl groups include phenyl, naphthyl, fluorenyl, and anthryl. However, aryl in no way encompasses or overlaps with heteroaryl, as defined below. When one or more aryl groups are fused to a heteroaryl, the resulting ring system is a heteroaryl. When one or more aryl groups are fused to a heterocyclyl, the resulting ring system is a heterocyclyl.

[0347] "Cyano" refers to the radical -CN.

[0348] "Keto" or "oxo" refers to the =O group

[0349] "Carbamoyl" means -OC(O)NR y R z "O-carbamoyl" refers to the -NR group y C(O)OR z The "N-carbamoyl" group refers to both the R y and R z is independently selected from the group consisting of hydrogen, alkyl, aryl, haloalkyl, or heteroaryl, each of which is optionally substituted.

[0350] "Carboxyl" or "carboxylic acid" refers to --C(O)OH.

[0351] "Ester" refers to both -OC(O)R and -C(O)OR, where R is a substituent, each of which may be optionally substituted as defined herein.

[0352] "Cycloalkyl" refers to saturated or partially unsaturated cyclic alkyl groups having single or multiple rings, including fused, bridged, and spiro ring systems. The term "cycloalkyl" includes cycloalkenyl groups (i.e., cyclic groups having at least one double bond). Cycloalkyl, as used herein, refers to cycloalkenyl groups having 3 to 15 ring carbon atoms (i.e., C 3~20 cycloalkyl), 3 to 12 ring carbon atoms (i.e., C 3~12 cycloalkyl), 3 to 10 ring carbon atoms (i.e., C 3~10 cycloalkyl), 3 to 8 ring carbon atoms (i.e., C 3~8 cycloalkyl) or 3 to 6 ring carbon atoms (i.e., C 3~6 Examples of cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and bicyclo[2.2.2]octan-1-yl. A cycloalkyl may be attached to the remainder of the molecule by a single ring atom (e.g., as a substituent) or by two ring atoms (e.g., as a linker).

[0353] "Ethylene glycol unit" refers to a divalent monomer having the structure -CH2CH2O-, which may be repeated or extended into longer chains. A linker segment can have up to 12 ethylene glycol units, or more typically up to 6 ethylene glycol units.

[0354] A "propylene glycol unit" refers to a divalent monomer having the structure -CH(CH)-CHO-, which may be repeated or extended into longer chains. A linker segment can have up to 12 propylene glycol units, or more typically up to 6 propylene glycol units.

[0355] "Halogen" or "halo" includes fluoro, chloro, bromo and iodo.

[0356] "Haloalkyl" refers to an unbranched or branched alkyl group, as defined above, in which one or more hydrogen atoms are replaced by halogen. For example, if a residue is substituted with more than one halogen, the residue may be referred to by using a prefix corresponding to the number of halogen moieties attached. Dihaloalkyl and trihaloalkyl refer to alkyl substituted with two ("di") or three ("tri") halo groups, which may, but are not necessarily, the same halogen. Examples of haloalkyl include difluoromethyl (-CHF2) and trifluoromethyl (-CF3).

[0357] "Heteroalkyl" refers to an alkyl group in which one or more carbon atoms (and any associated hydrogen atoms) are each independently replaced with the same or different heteroatoms (such as N, O, or S). The term "heteroalkyl" includes unbranched or branched saturated chains having carbon and heteroatoms. By way of example, one, two, or three carbon atoms may be independently replaced with the same or different heteroatoms. Heteroatom groups include, but are not limited to, -N(R)-, -O-, -S-, -S(O)-, -S(O)-, and the like, where R is H, alkyl, aryl, cycloalkyl, heteroalkyl, heteroaryl, or heterocyclyl, each of which is optionally substituted. Examples of heteroalkyl groups include -OCH, -CHOCH, -SCH, -CHSCH, -NRCH, and -CHNRCH, where R is hydrogen, alkyl, aryl, arylalkyl, heteroalkyl, or heteroaryl, each of which is optionally substituted. As used herein, heteroalkyl includes 1 to 10 carbon atoms, 1 to 8 carbon atoms, or 1 to 4 carbon atoms; and 1 to 3 heteroatoms, 1 to 2 heteroatoms, or 1 heteroatom.

[0358] "Heteroaryl" refers to a 5-15 membered, or more typically 5-12 membered, aromatic group having a monocyclic, polycyclic, or fused polycyclic ring and having 1 to 3 ring heteroatoms independently selected from nitrogen, oxygen, and sulfur. As used herein, heteroaryl refers to a heteroaryl having 3 to 12 ring carbon atoms (i.e., C 3~12 heteroaryl) or 3 to 8 carbon ring atoms (i.e., C 3~8 Heteroaryl): and 1 to 5 heteroatoms, 1 to 4 heteroatoms, 1 to 3 ring heteroatoms, 1 to 2 ring heteroatoms, or 1 ring heteroatom independently selected from nitrogen, oxygen, and sulfur. Examples of heteroaryl groups include pyrimidinyl, purinyl, pyridyl, pyridazinyl, benzothiazolyl, and pyrazolyl. Examples of fused heteroaryl rings include, but are not limited to, benzo[d]thiazolyl, quinolinyl, isoquinolinyl, benzo[b]thiophenyl, indazolyl, benzo[d]imidazolyl, pyrazolo[1,5-a]pyridinyl, and imidazo[1,5-a]pyridinyl, where the heteroaryl can be bonded through any of the rings of the fused system. Any aromatic ring having a single ring or multiple fused rings containing at least one heteroatom is considered heteroaryl, regardless of attachment to the rest of the molecule (i.e., through any one of the fused rings). Heteroaryl does not encompass or overlap with aryl, as defined above. Heteroaryl may be attached to the remainder of the molecule by a single ring atom (e.g., as a substituent) or by two ring atoms (e.g., as a linker).

[0359] "Heterocyclyl" refers to a 3- to 15-membered, or more typically 5- to 12-membered, saturated or unsaturated cyclic alkyl group having 1 to 3 ring heteroatoms independently selected from nitrogen, oxygen, and sulfur. The term "heterocyclyl" includes heterocycloalkenyl groups (i.e., heterocyclyl groups having at least one double bond), bicyclic heterocyclyl groups, bridged heterocyclyl groups, fused heterocyclyl groups, and spiroheterocyclyl groups. Heterocyclyls may be monocyclic or polycyclic, and polycyclic rings may be fused, bridged, or spiro. Any non-aromatic ring containing at least one heteroatom is considered heterocyclyl (i.e., may be bonded via a carbon atom or a heteroatom), regardless of attachment to the rest of the molecule. Furthermore, the term heterocyclyl is intended to encompass any non-aromatic ring containing at least one heteroatom, which may be fused to an aryl or heteroaryl ring, regardless of attachment to the rest of the molecule. As used herein, heterocyclyl has 3 to 15 ring atoms (e.g., 3-15-membered heterocyclyl, 3-12-membered heterocyclyl, 4-10-membered heterocyclyl, 4-8-membered heterocyclyl, or 4-6-membered heterocyclyl) having 1 to 5 ring heteroatoms, 1 to 4 ring heteroatoms, 1 to 3 ring heteroatoms, 1 to 2 ring heteroatoms, or 1 ring heteroatom independently selected from nitrogen, sulfur, or oxygen. The heterocyclyl may contain one or more oxo and / or thioxo groups. Examples of heterocyclyl groups include pyrrolidinyl, piperidinyl, piperazinyl, oxetanyl, dioxolanyl, azetidinyl, azetidinyl, morpholinyl, thiomorpholinyl, 4- to 7-membered sultam, 4- to 7-membered cyclic carbamate, 4- to 7-membered cyclic carbonate, 4- to 7-membered cyclic sulfide, and morpholinyl.As used herein, heterocyclyl can include a bridged structure (i.e., a "bridged heterocyclyl"), in which a 4- to 10-membered ring moiety connected at two non-adjacent atoms of the heterocyclyl has one or more (e.g., one or two) 4- to 10-membered ring moieties having at least one heteroatom, each heteroatom being independently selected from nitrogen, oxygen, and sulfur. As used herein, bridged heterocyclyl includes bicyclic and tricyclic ring systems. Similarly, as used herein, the term "spiro-heterocyclyl" refers to a ring system in which a 3- to 10-membered heterocyclyl has one or more additional rings, where the one or more additional rings are 3- to 10-membered cycloalkyl or 3- to 10-membered heterocyclyl, and a single atom of the one or more additional rings is also an atom of the 3- to 10-membered heterocyclyl. Examples of spiro-heterocyclyl rings include bicyclic and tricyclic ring systems such as 2-oxa-7-azaspiro[3.5]nonanyl, 2-oxa-6-azaspiro[3.4]octanyl, and 6-oxa-1-azaspiro[3.3]heptanyl. Examples of fused heterocyclyl rings include, but are not limited to, 1,2,3,4-tetrahydroisoquinolinyl, 1-oxo-1,2,3,4-tetrahydroisoquinolinyl, 1-oxo-1,2-dihydroisoquinolinyl, 4,5,6,7-tetrahydrothieno[2,3-c]pyridinyl, indolinyl, 2,3-dihydro-1H-isoindolyl, and isoindolinyl, where the heterocyclyl can be attached via either ring of the fused system. As used herein, a bicyclic heterocyclyl group is a heterocyclyl group attached at two points to another cyclic group, which may itself be a heterocyclic or carbocyclic group. A heteroaryl may be attached to the remainder of the molecule by a single ring atom (e.g., as a substituent) or by two ring atoms (e.g., as a linker).

[0360] "Fused" refers to rings that are connected to adjacent rings and share two adjacent ring atoms that form a covalent bond.

[0361] "Bridged" refers to a ring fusion in which non-adjacent atoms on the rings are joined by a divalent substituent, such as an alkenyl group, an alkenyl group containing one or two heteroatoms, or a single heteroatom. Quinuclidinyl and adamantanyl are examples of bridged ring systems.

[0362] "Spiro" refers to a ring substituent that is joined by two bonds at the same carbon atom. Examples of spiro groups include 1,1-diethylcyclopentane, dimethyl-dioxolane, and 4-benzyl-4-methylpiperidine, with cyclopentane and piperidine each being a spiro substituent.

[0363] "Hydroxyl" or "hydroxy" refers to the group -OH. "Hydroxyalkyl" refers to an unbranched or branched alkyl group, as defined above, in which one or more hydrogen atoms have been replaced by hydroxyl.

[0364] "Nitro" refers to the -NO2 group.

[0365] "Imino" means C=NR y or =NC(O)R y refers to a group containing a C=N double bond such as R y is selected from the group consisting of hydrogen, alkyl, aryl, cyano, haloalkyl, or heteroaryl, each of which may be optionally substituted. Imino may be a linker segment by bonding to the remaining molecule at the carbon and nitrogen, respectively. "Sulfoximine" or "sulfoximino" refers to a compound having the following general formula: [ka]

[0366] (In the formula, R yis selected from the group consisting of hydrogen, alkyl, amino, aryl, cyano, haloalkyl, heterocyclyl, or heteroaryl; V and W are each independently selected from a bond, alkyl, amino, aryl, haloalkyl, heterocyclyl, or heteroaryl, each of which is optionally substituted; R y and V, R y and W, and V and W may be joined together with the atoms to which they are attached to form a ring) and may be substituted or unsubstituted portions of the group. The sulfoximine may be a linker segment by bonding to the remaining molecule at the sulfur and nitrogen, respectively.

[0367] "Sulfonyl" refers to the group -S(O)2R, where R is a substituent or defined group.

[0368] "Alkylsulfonyl" refers to the group -S(O)2R, where R is a substituent or defined group.

[0369] "Alkylsulfinyl" refers to the group -S(O)R, where R is a substituent or defined group.

[0370] "Thiocyanate" -SCN.

[0371] "Thiol" refers to the group -SR, where R is a substituent or defined group.

[0372] "Thioxo" or "thione" refers to the (=S) or (S) group.

[0373] Certain commonly used alternative chemical names may be used. For example, divalent groups such as divalent "alkyl" groups, divalent "aryl" groups, etc. may also be referred to as "alkylene" groups, "alkenyl" groups, "arylene" groups, or "arylenyl" groups, respectively. Similarly, unless otherwise explicitly stated, when a combination of groups is referred to herein as one moiety, such as arylalkyl, the last-specified group contains the atom through which this moiety is attached to the rest of the molecule.

[0374] "Optionally" or "optionally" means that the subsequently described event or circumstance may or may not occur, and the description includes cases where said event or circumstance occurs and cases where it does not occur. Similarly, the term "optionally substituted" refers to any one or more hydrogen atoms of the specified atom or group that may or may not be replaced by a non-hydrogen moiety. "Optionally substituted" refers to zero to the maximum number of possible substitutions and is independent at each occurrence. When the term "substituted" is used, the substitution must be at a substitutable hydrogen atom of the indicated substituent. Optional substitution may be the same as or different from (necessary) substitution.

[0375] When a moiety is "optionally substituted," and when reference is made to a general term such as "alkyl," "alkenyl," "alkynyl," "haloalkyl," "cycloalkyl," "aryl," or "heteroaryl," that general term is intended to be a general term that includes, but is not limited to, (C 1~3 alkyl), (C 4~6 alkyl), -O(C 1~4 alkyl), (C 3~10 cycloalkyl), O-(C 3~10

[0023] It can refer to any of the specifically listed terms that it precedes, such as cycloalkyl. For example, "any aryl" includes both "aryl" and "-O(aryl)," as well as examples of aryl such as phenyl or naphthyl. Similarly, the term "any heterocyclyl" includes both the terms "heterocyclyl" and "O-(heterocyclyl)," as well as examples of heterocyclyl such as oxetanyl, tetrahydropyranyl, morpholino, piperidinyl, and the like. Similarly, the term "any heteroaryl" includes the terms "heteroaryl" and "O-(heteroryl)," as well as specific heteroaryls such as pyridine.

[0376] Some compounds of Formula (I) may exist as "stereoisomers" or mixtures of stereoisomers. Stereoisomers refer to compounds that are composed of the same atoms connected by the same bonds but have different three-dimensional structures and are not interconvertible. The compounds of the present disclosure, or their pharmaceutically acceptable salts, may contain one or more asymmetric centers and thus give rise to enantiomers (two stereoisomers whose molecules are non-superimposable mirror images of one another), diastereomers, and other stereoisomers that can be defined in terms of absolute stereochemistry as (R)- or (S)-. The present disclosure is intended to encompass all such possible isomers, as well as their racemic mixtures (i.e., equal amounts of (R) and (S) enantiomers) and optically pure forms. Optically active (+) and (-), (R)- and (S)-isomers can be prepared using chiral synthons or chiral reagents, or resolved using conventional techniques, such as HPLC with chiral columns.

[0377] The present disclosure also includes "deuterated analogs" of compounds of Formula I in which one to n hydrogens bonded to a carbon atom (where n is the number of hydrogens in the molecule) have been replaced by deuterium. Such compounds exhibit improved resistance to metabolism and are therefore useful for increasing the half-life of any compound of Formula I when administered to mammals, particularly humans. See, e.g., Foster, "Deuterium Isotope Effects in Studies of Drug Metabolism," Trends Pharmacol. Sci. 5(12):524-527 (1984). Such compounds are synthesized by means well known in the art, for example, by using starting materials in which one or more hydrogens have been replaced by deuterium.

[0378] Deuterium-labeled or substituted therapeutic compounds of the present disclosure may have improved DMPK (drug metabolism and pharmacokinetic) properties related to distribution, metabolism, and excretion (ADME). Substitution with heavier isotopes, such as deuterium, may confer certain therapeutic advantages due to greater metabolic stability, e.g., increased in vivo half-life, reduced dosage requirements, and / or improved therapeutic index. 18 F-labeled compounds can be useful for PET or SPECT studies.Isotopically labeled compounds of the present disclosure can generally be prepared by carrying out the procedures disclosed in the schemes or examples and the preparations described below, by substituting readily available isotopically labeled reagents for non-isotopically labeled reagents.It is understood that deuterium in this context is considered as a substituent in the compound of formula I.

[0379] The concentration of such heavier isotopes, specifically deuterium, can be defined by the isotopic enrichment factor. In the compounds of the present disclosure, any atom not specifically designated as a particular isotope is intended to represent any stable isotope of that atom. Unless otherwise specified, when a position is specifically designated as "H" or "hydrogen," the position is understood to have hydrogen at its natural abundance isotopic composition. Thus, in the compounds of the present disclosure, any atom specifically designated as deuterium (D) is intended to represent deuterium.

[0380] In many cases, the compounds of the present disclosure are capable of forming acid and / or base salts by virtue of the presence of amino and / or carboxyl groups or groups similar thereto.

[0381] Pharmaceutically acceptable salts, hydrates, or solvates of the compounds described herein are also provided. "Pharmaceutically acceptable" or "physiologically acceptable" refers to compounds, salts, compositions, dosage forms, and other substances that are useful in preparing pharmaceutical compositions suitable for veterinary or human pharmaceutical use.

[0382] The term "pharmaceutically acceptable salt" of a given compound refers to a salt that retains the biological effectiveness and properties of the given compound and is not biologically or otherwise undesirable. "Pharmaceutically acceptable salts" or "physiologically acceptable salts" include, for example, salts with inorganic acids and salts with organic acids. Furthermore, when a compound described herein is obtained as an acid addition salt, the free base can be obtained by basifying a solution of the acid salt. Conversely, when the product is a free base, an addition salt, particularly a pharmaceutically acceptable addition salt, can be produced by dissolving the free base in a suitable organic solvent and treating the solution with an acid, according to conventional procedures for preparing acid addition salts from basic compounds. Those skilled in the art will recognize various synthetic methods that can be used to prepare non-toxic pharmaceutically acceptable addition salts. Pharmaceutically acceptable acid addition salts can be prepared from inorganic and organic acids. Salts derived from inorganic acids include hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like. Salts derived from organic acids include acetic acid, propionic acid, glycolic acid, pyruvic acid, oxalic acid, malic acid, malonic acid, succinic acid, maleic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, salicylic acid, and the like. Similarly, pharmaceutically acceptable base addition salts can be prepared from inorganic and organic bases. Salts derived from inorganic bases include, by way of example only, sodium, potassium, lithium, ammonium, calcium, and magnesium salts.Salts derived from organic bases include, but are not limited to, alkylamines (i.e., NH2(alkyl)), dialkylamines (i.e., HN(alkyl)2), trialkylamines (i.e., N(alkyl)3), substituted alkylamines (i.e., NH2(substituted alkyl)), di(substituted alkyl)amines (i.e., HN(substituted alkyl)2), tri(substituted alkyl)amines (i.e., N(substituted alkyl)3), alkenylamines (i.e., NH2(alkenyl)), dialkenylamines (i.e., HN(alkenyl)2), trialkenylamines (i.e., Included are salts of primary, secondary, and tertiary amines such as N(alkenyl)s, substituted alkenylamines (i.e., NH(substituted alkenyl)s), di(substituted alkenyl)amines (i.e., HN(substituted alkenyl)s), tri(substituted alkenyl)amines (i.e., N(substituted alkenyl)s), mono-, di-, or tricycloalkylamines (i.e., NH(cycloalkyl), HN(cycloalkyl), N(cycloalkyl)s), mono-, di-, or triarylamines (i.e., NH(aryl), HN(aryl), N(aryl)s), or mixed amines. Specific examples of suitable amines include, by way of example only, isopropylamine, trimethylamine, diethylamine, tri(iso-propyl)amine, tri(n-propyl)amine, ethanolamine, 2-dimethylaminoethanol, piperazine, piperidine, morpholine, N-ethylpiperidine, and the like.

[0383] The term "substituted" means that any one or more hydrogen atoms on the specified atom or group have been replaced with one or more substituents other than hydrogen, provided that the normal valence of the specified atom is not exceeded. The one or more substituents include, but are not limited to, alkyl, alkenyl, alkynyl, alkoxy, acyl, amino, amido, amidino, aryl, azido, carbamoyl, carboxyl, carboxyl ester, cyano, guanidino, halo, haloalkyl, haloalkoxy, heteroalkyl, heteroaryl, heterocyclyl, hydroxy, hydrazino, imino, oxo, nitro, alkylsulfinyl, sulfonic acid, alkylsulfonyl, thiocyanate, thiol, thione, or combinations thereof. Polymers or similar indefinite structures arrived at by defining a substituent with an infinite number of additional substituents (e.g., substituted aryl with a substituted alkyl that is itself substituted with a substituted aryl group that is further substituted with a substituted heteroalkyl group, etc.) are not intended to be encompassed herein. Unless otherwise specified, the maximum number of consecutive substitutions in the compounds described herein is three. For example, consecutive substitution of a substituted aryl group with two other substituted aryl groups is limited to ((substituted aryl)substituted aryl)substituted aryl. Similarly, the above definitions are not intended to include impermissible substitution patterns (e.g., methyl substituted with five fluorines or a heteroaryl group having two adjacent oxygen ring atoms). Such impermissible substitution patterns are well known to those skilled in the art. When used to modify a chemical group, the term "substituted" may describe other chemical groups defined herein. Unless otherwise specified, when a group is described as optionally substituted, any substituents on that group are themselves unsubstituted. For example, in some embodiments, the term "substituted alkyl" refers to an alkyl group having one or more substituents, including hydroxyl, halo, alkoxy, cycloalkyl, heterocyclyl, aryl, and heteroaryl.In other embodiments, one or more substituents may be further substituted with halo, alkyl, haloalkyl, hydroxyl, alkoxy, cycloalkyl, heterocyclyl, aryl, or heteroaryl, each of which is substituted. In other embodiments, the substituents may be further substituted with halo, alkyl, haloalkyl, alkoxy, hydroxyl, cycloalkyl, heterocyclyl, aryl, or heteroaryl, each of which is unsubstituted. Those skilled in the art will recognize that the substituents and other moieties of the compounds of the general formula herein should be selected to achieve a compound that is sufficiently stable to produce a pharmaceutically useful compound that can be formulated into an acceptably stable pharmaceutical composition. Compounds with such stability are intended to be within the scope of the present invention. It should be understood by those skilled in the art that any combination of the above definitions and substituents should not result in an inoperable chemical species or compound.

[0384] As used herein, "pharmaceutically acceptable carrier" or "pharmaceutically acceptable excipient" includes any and all solvents, dispersion media, coating agents, antibacterial and antifungal agents, isotonic and absorption delaying agents, etc. The use of such media and agents for pharmaceutically active substances is well known in the art. Except insofar as any conventional media or agent is incompatible with the active ingredient, its use in the therapeutic composition is contemplated. Supplementary active ingredients can also be incorporated into the composition.

[0385] A "solvate" is formed by the interaction of a solvent and a compound. Solvates of salts of the compounds described herein are also provided. Hydrates of the compounds described herein are also provided. Targeted IRAK4 Degradation

[0386] Compounds of the present disclosure are demonstrated by cell-based profiling to selectively degrade IRAK4.

[0387] The degradation mechanisms and selectivities of two representative compounds with LHMs targeting CRBN (Formula (IIA)) and two representative compounds with LHMs targeting VHL (Formula (IIB)) were evaluated and discussed herein. For comparison, three compounds known to degrade IRAK4 were also evaluated. Table 1 shows the structures of selected compounds. [Table 1-1] [Table 1-2] [Table 1-3]

[0388] More specifically, the cellular degradation of IRAK4 of selected compounds was evaluated using three different assay formats: HiBiT assay, HTRF assay, and Western blotting. All compounds demonstrated consistent and reproducible degradation across these three assays. Notably, among the selected compounds, compound 47 was shown to be the most effective degrader in terms of Dmax, achieving 99% degradation as assessed by Western blot analysis. Furthermore, representative compounds demonstrated equivalent or superior degradation (Dmax) compared to known compounds with similar LHMs (compounds a1, a2, and b1). max ) was shown.

[0389] To further confirm that IRAK4 degradation is mediated by the ubiquitin-proteasome system, compounds of formula (I) were profiled in the presence of proteasome inhibitors, ligase inhibitors, or excess concentrations of corresponding monofunctional compounds, such as compounds with only an IRAK4-binding moiety or only an LHM. Pretreatment under any of these conditions restored IRAK4 protein levels to those of untreated cells, demonstrating the bifunctional compound's on-mechanism.

[0390] The specificity of IRAK4 degradation by the disclosed compounds was assessed by first assessing the degradation of CRBN neosubstrates Ikaros, Aiolos, and GSPT1, and secondly assessing the degrader's effect on the highly related target IRAK1. Neosubstrate profiling demonstrated that one known compound, comparative compound a2, degraded both Ikaros and Aiolos, while compounds 13, 24, 47, and 35 showed no neosubstrate degradation. Furthermore, none of the assayed compounds affected IRAK1 levels, demonstrating specificity for IRAK4 over IRAK1 degradation. Finally, none of the assayed compounds affected cell viability as assessed by CellTiter-Glo. Table 2 summarizes the degradation results for selected compounds targeting CRBN.

[0391] [Table 2] Table 3 summarizes the degradation results for selected compounds targeting VHL.

[0392] [Table 3]

[0393] Pharmaceutical Compositions and Uses of Bifunctional Compounds of Formula (I)

[0394] The bifunctional compounds of formula (I) degrade IRAK4 and therefore prove useful in treating disease indications or disorders involving the function of IRAK4, such as signal transduction or scaffolding.

[0395] Various embodiments provide pharmaceutical compositions comprising a compound of formula (I) or any one of the substructures or compounds of Table 5 and a pharmaceutically acceptable carrier.

[0396] A further embodiment provides a method of treating cancer, an inflammatory disorder, an autoimmune disorder, or a metabolic disorder, comprising administering to a subject in need thereof a therapeutically effective amount of a compound of Formula (I), or any one of the substructures or compounds of Table 5.

[0397] Examples of cancers that can be treated include lymphomas, leukemias, including, for example, acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS).

[0398] Examples of metabolic disorders include, but are not limited to, diabetes, including type I and type II diabetes, metabolic syndrome, dyslipidemia, obesity, glucose intolerance, hypertension, elevated serum cholesterol, and elevated triglycerides.

[0399] Examples of inflammatory disorders include rheumatoid arthritis (RA), inflammatory bowel disease (IBD), Crohn's disease, ulcerative colitis, necrotizing enterocolitis, gout, Lyme disease, arthritis, psoriasis, pelvic inflammatory disease, systemic lupus erythematosus (SLE), Sjogren's syndrome, inflammation associated with gastrointestinal infections including C. difficile, viral myocarditis, acute and chronic tissue injury, non-alcoholic steatohepatitis (NASH), alcoholic hepatitis, and kidney disease, including chronic kidney disease and diabetic kidney disease.

[0400] A further embodiment provides a method of treating a disease or condition associated with inflammation, or a metabolic disorder, a gastrointestinal disorder, or cancer, or the like, comprising administering a compound of formula (I) in combination with one or more compounds useful in the treatment of such a disease to a subject, particularly a human subject, in need thereof.

[0401] In some embodiments, the compound of the present disclosure is co-formulated with one or more additional active ingredients. In some embodiments, the other active ingredients are administered in separate dosage forms at approximately the same time. In some embodiments, the other active ingredients are administered sequentially and may be administered at different times relative to the compound of the present disclosure. [Example]

[0402] Preparation of Compounds of Formula (I) Example 1 [ka] N-(4-(5-(6-(3-cyanopyrrolo[1,2-b]pyridazin-7-yl)-4-((tetrahydro-2H-pyran-4-yl)amino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)bicyclo[2.2.2]octan-1-yl)-3-(2-(2-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)ethoxy)ethoxy)propanamide

[0403] To a mixture of 7-(5-(5-(4-aminobicyclo[2.2.2]octan-1-yl)-1,3,4-thiadiazol-2-yl)-4-((tetrahydro-2H-pyran-4-yl)amino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile bishydrochloride (BB1, 16.0 mg, 0.0249 mmol), 3-[2-[2-[[2-(2,6-dioxo-3-piperidyl)-1,3-dioxo-isoindolin-4-yl]amino]ethoxy]ethoxy]propanoic acid (13.0 mg, 0.0299 mmol) and HATU (9.97 mg, 0.0262 mmol) in DMF (0.125 mL) was added DIPEA (0.0143 mL, 0.0799 mmol). The resulting solution was stirred at room temperature for 12 hours. The crude solution was purified by preparative HPLC (Gemini C18, eluent: 10-64% acetonitrile / HO / 0.1% TFA) and lyophilized to give N-(4-(5-(6-(3-cyanopyrrolo[1,2-b]pyridazin-7-yl)-4-((tetrahydro-2H-pyran-4-yl)amino)pyridin-3-yl)-1,3,4-thiadiazol-2-6yl)bicyclo[2.2.2]octan-1-yl)-3-(2-(2-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)ethoxy)ethoxy)propanamide as the TFA salt. ES / MS: 942.476 (M+H)+ ); 1 H NMR (400 MHz, Methanol-d4) δ 10.17 (d, J = 7.7 Hz, 1H), 9.03 (s, 1H), 8.68 (s, 1H), 8.66 - 8.58 (m, 2H), 8.11 (d, J = 5.1 Hz, 1H), 7.79 (s, 1H), 7.59 (dd, J = 8.6, 7.1 Hz, 1H), 7.21 (d, J = 5.1 Hz, 1H), 7.08 (t, J = 7.8 Hz, 2H), 6.34 (s, 1H), 4.97 (dd, J = 12.2, 5.3 Hz, 1H), 4.01 (dt, J = 12.1, 3.9 Hz, 2H), 3.74 (t, J = 5.3 Hz, 2H), 3.70 - 3.56 (m, 9H), 3.49 (t, J = 5.3 Hz, 2H), 2.83 - 2.64 (m, 3H), 2.30 (t, J = 6.0 Hz, 2H), 2.19 - 2.11 (m, 2H), 2.11 - 2.01 (m, 9H), 1.85 - 1.73 (m, 3H). Example 2 [ka]

[0404] N-(4-(5-(6-(3-cyanopyrrolo[1,2-b]pyridazin-7-yl)-4-((tetrahydro-2H-pyran-4-yl)amino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)bicyclo[2.2.2]octan-1-yl)-3-(2-(2-(2-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)ethoxy)ethoxy)ethoxy)propanamide

[0405] N-(4-(5-(6-(3-cyanopyrrolo[1,2-b]pyridazin-7-yl)-4-((tetrahydro-2H-pyran-4-yl)amino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)bicyclo[2.2.2]octan-1-yl)-3-(2-(2-(2-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)ethoxy)ethoxy)ethoxy)propanamide is a 7-(5-(5-(4-aminobicyclo[2.2.2]octan-1-yl)-1,3,4-thiadiazol-2-yl)-4-((tetrahydro-2H-pyran-4-yl)amino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)amino Prepared according to the procedure of Example 2, starting from (lysin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile bishydrochloride (BB1, 18.0 mg, 0.0281 mmol) and substituting 3-[2-[2-[[2-(2,6-dioxo-3-piperidyl)-1,3-dioxo-isoindolin-4-yl]amino]ethoxy]ethoxy]propanoic acid (13.0 mg, 0.0299 mmol) for 3-(2-(2-(2-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)ethoxy)ethoxy)propanoic acid (14.8 mg, 0.0309 mmol). ES / MS: 986.572 (M+H + ); 1H NMR (400 MHz, Acetonitrile-d3) δ 10.19 (d, J = 7.6 Hz, 1H), 9.12 (s, 1H), 8.68 - 8.59 (m, 3H), 8.11 (d, J = 5.1 Hz, 1H), 7.74 (s, 1H), 7.56 (dd, J = 8.6, 7.1 Hz, 1H), 7.22 (d, J = 5.1 Hz, 1H), 7.06 (dd, J = 19.2, 7.7 Hz, 2H), 6.34 (s, 1H), 4.96 (dd, J = 12.4, 5.4 Hz, 1H), 4.01 (dt, J = 11.9, 3.8 Hz, 2H), 3.72 (t, J = 5.3 Hz, 2H), 3.65 (tt, J = 5.3, 3.1 Hz, 6H), 3.61 - 3.54 (m, 3H), 3.49 (t, J = 5.3 Hz, 2H), 2.86 - 2.58 (m, 2H), 2.31 (t, J = 6.1 Hz, 2H), 2.19 - 2.03 (m, 12H), 1.84 - 1.73 (m, 2H). Example 3 [ka]

[0406] Synthesis of N-((1r,4r)-4-(5-(6-(3-cyanopyrrolo[1,2-b]pyridazin-7-yl)-4-(isopropylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)cyclohexyl)-3-(2-(2-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)ethoxy)ethoxy)propanamide

[0407] To a mixture of 7-(5-(5-((trans)-4-aminocyclohexyl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile bishydrochloride (BB2, 10.0 mg, 0.0188 mmol), 3-(2-(2-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)ethoxy)ethoxy)propanoic acid (10.0 mg, 0.0231 mmol), and HATU (10.0 mg, 0.0263 mmol) in DMF (0.5 mL) was added DIPEA (0.0170 mL, 0.0976 mmol). The resulting solution was stirred at room temperature for 20 minutes. The crude solution was purified by preparative HPLC (Gemini C18, eluent: 10-45% acetonitrile / HO / 0.1% TFA) and lyophilized to give N-((trans)-4-(5-(6-(3-cyanopyrrolo[1,2-b]pyridazin-7-yl)-4-(isopropylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)cyclohexyl)-3-(2-(2-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)ethoxy)ethoxy)propenamide as the TFA salt. ES / MS: 874.659 (M+H) + ); 1H NMR (400 MHz, Methanol-d4) δ 8.79 (d, J = 2.1 Hz, 1H), 8.72 (d, J = 1.8 Hz, 2H), 8.10 (d, J = 5.1 Hz, 1H), 7.97 (s, 1H), 7.58 (dd, J = 8.6, 7.1 Hz, 1H), 7.26 (d, J = 5.1 Hz, 1H), 7.13 (d, J = 8.5 Hz, 1H), 7.05 (d, J = 7.0 Hz, 1H), 5.09 (dd, J = 12.5, 5.5 Hz, 1H), 4.34 (p, J = 6.4 Hz, 1H), 3.77 (td, J = 5.6, 2.6 Hz, 5H), 3.73 - 3.62 (m, 3H), 3.60 - 3.48 (m, 2H), 3.23 - 3.09 (m, 1H), 2.89 (ddd, J = 17.7, 14.3, 5.0 Hz, 1H), 2.83 - 2.66 (m, 2H), 2.45 (t, J = 5.9 Hz, 2H), 2.30 - 1.99 (m, 5H), 1.81 - 1.63 (m, 2H), 1.52 (d, J = 6.4 Hz, 6H), 1.50 - 1.35 (m, 3H). Example 4 [ka]

[0408] N-((1r,4r)-4-(5-(6-(3-cyanopyrrolo[1,2-b]pyridazin-7-yl)-4-(isopropylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)cyclohexyl)-3-(2-(2-(2-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)ethoxy)ethoxy)ethoxy)propanamide

[0409] N-((trans)-4-(5-(6-(3-cyanopyrrolo[1,2-b]pyridazin-7-yl)-4-(isopropylamino)pyridin-3-yl)-1,3,4-thiadiazol-2-yl)cyclohexyl)-3-(2-(2-(2-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)ethoxy)ethoxy)ethoxy)propenamide is 7-(5-(5-((trans)-4-aminocyclohexyl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2- b] Prepared according to the procedure of Example 3, starting with pyridazine-3-carbonitrile bishydrochloride (BB2, 10.0 mg, 0.0188 mmol) and substituting 3-(2-(2-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)ethoxy)ethoxy)propanoic acid (10.0 mg, 0.0231 mmol) for 3-(2-(2-(2-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)ethoxy)ethoxy)ethoxy)propanoic acid (10.0 mg, 0.0209 mmol). ES / MS: 918.750 (M+H + ); 1H NMR (400 MHz, Methanol-d4) δ 8.79 (d, J = 2.2 Hz, 1H), 8.72 (d, J = 2.2 Hz, 1H), 8.70 (s, 1H), 8.10 (d, J = 5.1 Hz, 1H), 7.97 (s, 1H), 7.55 (dd, J = 8.6, 7.1 Hz, 1H), 7.26 (d, J = 5.1 Hz, 1H), 7.11 (d, J = 8.6 Hz, 1H), 7.01 (d, J = 7.0 Hz, 1H), 5.07 (dd, J = 12.4, 5.5 Hz, 1H), 4.34 (p, J = 6.4 Hz, 1H), 3.80 - 3.72 (m, 5H), 3.70 (s, 4H), 3.69 - 3.59 (m, 4H), 3.53 (t, J = 5.2 Hz, 2H), 3.24 (tt, J = 12.0, 3.6 Hz, 1H), 2.89 (ddd, J = 17.8, 14.2, 5.2 Hz, 1H), 2.83 - 2.65 (m, 2H), 2.44 (t, J = 6.0 Hz, 2H), 2.27 (d, J = 13.1 Hz, 2H), 2.19 - 2.04 (m, 3H), 1.75 (qd, J = 13.0, 3.3 Hz, 2H), 1.52 (d, J = 6.4 Hz, 6H), 1.45 (dd, J = 12.8, 3.4 Hz, 2H). Example 5 [ka] 7-(5-(5-(4-(8-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)amino)octanoyl)piperazin-1-yl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile

[0410] HATU (19 mg, 0.05 mmol) and 8-{[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindol-5-yl]amino}octanoic acid (14 mg, 0.03 mmol) were dissolved in DMF (0.15 M) and triethylamine (7 mg, 0.07 mmol). The reaction was stirred at room temperature for 10 minutes, after which 7-[4-(isopropylamino)-5-[5-(piperazin-1-yl)-1,3,4-thiadiazol-2-yl]pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile (15 mg, 0.03 mmol), BB4, was added. The reaction was then stirred for 16 hours, then filtered through a syringe filter and purified by HPLC to give 7-(5-{5-[4-(8-{[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindol-5-yl]amino}octanoyl)piperazin-1-yl]-1,3,4-thiadiazol-2-yl}-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile (3.6 mg, 13%). LCMS: C 43 H 46 N 12 05S Theoretical value: 843.0, Measured value: m / z = 843.9 [M+H] + ; 1H NMR (500 MHz, DMSO-d6) δ 11.06 (s, 1H), 9.50 (s, 1H), 8.98 (d, J = 2.1 Hz, 1H), 8.85 (d, J = 2.1 Hz, 1H), 8.57 (s, 1H), 8.06 (d, J = 4.9 Hz, 1H), 8.02 (s, 1H), 7.57 (d, J = 8.3 Hz, 1H), 7.24 (d, J = 5.0 Hz, 1H), 7.12 (s, 1H), 6.95 (d, J = 2.1 Hz, 1H), 6.85 (dd, J = 8.2, 2.1 Hz, 1H), 6.56 (s, 1H), 5.03 (dd, J = 12.7, 5.4 Hz, 1H), 4.18 (s, 1H), 3.68 (d, J = 4.6 Hz, 1H), 3.64 (s, 2H), 3.58 (d, J = 5.8 Hz, 2H), 3.18 (d, J = 7.4 Hz, 2H), 2.88 (ddd, J = 18.2, 13.8, 5.6 Hz, 1H), 2.60 (s, 1H), 2.39 (d, J = 7.5 Hz, 1H), 2.00 (d, J = 12.9 Hz, 1H), 1.62 - 1.54 (m, 2H), 1.53 (d, J = 6.8 Hz, 3H), 1.38 (d, J = 6.4 Hz, 8H), 1.36 - 1.32 (m, 6H). Example 6 [ka] 7-(5-(5-(4-(6-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)amino)hexanoyl)piperazin-1-yl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile

[0411] The title compound was synthesized from BB4 and 6-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)amino)hexanoic acid by amide coupling using general method A. LCMS: C 41 H 42 N 12 05S Theoretical value: 814.3, Measured value: m / z = 815.9 [M+H] + ; 1 H NMR (500 MHz, DMSO-d6) δ 11.06 (s, 1H), 9.20 (s, 1H), 8.94 (d, J = 2.3 Hz, 1H), 8.82 (d, J = 2.2 Hz, 1H), 8.56 (s, 1H), 8.09 (s, 1H), 8.00 (d, J = 4.7 Hz, 1H), 7.55 (dd, J = 19.1, 8.3 Hz, 1H), 7.20 (d, J = 4.8 Hz, 1H), 7.13 (s, 1H), 6.96 (d, J = 2.2 Hz, 1H), 6.85 (ddd, J = 10.6, 8.3, 2.1Hz, 1H), 6.54 (s, 3H), 5.03 (dd, J = 12.7, 5.2 Hz, 1H), 4.11 (s, 1H), 3.67 (d, J = 5.3 Hz, 2H), 3.18 (s, 2H), 2.88 (ddd, J = 16.5, 13.6, 5.4 Hz, 1H), 2.60 (s, 1H), 2.48 (s, 2H), 2.41 (t, J = 7.3 Hz, 1H), 2.00 (d, J = 12.9 Hz, 1H), 1.60 (tt, J = 15.2, 7.6 Hz, 3H), 1.43 (d, J = 7.5 Hz, 1H), 1.38 (d, J = 6.4 Hz, 6H). Example 7 [ka]

[0412] 7-(5-(5-(4-(3-(2-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)ethoxy)propanoyl)piperazin-1-yl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile

[0413] The title compound was synthesized from BB4 and 3-(2-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)ethoxy)propanoic acid by amide coupling using general method A. LCMS: C 40 H 40 N 12 O6S Theoretical value: 816.3 Measured value: m / z = 817.7 [M+H] + ; 1 H NMR (500 MHz, DMSO-d6) δ 11.11 (s, 1H), 9.37 (s, 1H), 8.97 (d, J = 2.1 Hz, 1H), 8.84 (d, J = 2.2 Hz, 1H), 8.52 (s, 1H), 8.05 (d, J = 6.1 Hz, 2H), 7.61 - 7.55 (m, 1H), 7.23 (d, J = 4.9 Hz, 1H), 7.14 (d, J = 8.6 Hz, 1H), 7.00 (d, J = 7.0 Hz, 1H), 6.56 (t, J = 5.5 Hz, 1H), 5.06 (dd, J = 12.8, 5.4 Hz, 1H), 4.16 (s, 1H), 3.73 (t, J = 6.3 Hz, 2H), 3.66 (dt, J = 14.4, 5.2 Hz, 6H), 3.61 - 3.52 (m, 4H), 3.48 (q, J = 5.4 Hz, 2H), 2.90 (ddd, J = 17.4, 13.8, 5.5 Hz, 1H), 2.67 (t, J = 6.3 Hz, 2H), 2.63 (s, 1H), 2.57 (d, J = 15.6 Hz, 1H), 2.10 - 2.03 (m, 1H), 1.39 (d, J = 6.3Hz, 6H). Example 8 [ka] 7-(5-(5-(4-(8-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)octanoyl)piperazin-1-yl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile

[0414] The title compound was synthesized from BB4 and 8-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)octanoic acid by amide coupling using general method A. LCMS: C 43 H 46 N 12 05S Theoretical value: 842.3, Measured value: m / z = 843.8 [M+H] + ; 1H NMR (500 MHz, DMSO-d6) δ 11.10 (s, 1H), 9.42 (s, 1H), 8.97 (d, J = 2.2 Hz, 1H), 8.84 (d, J = 2.2 Hz, 1H), 8.56 (s, 1H), 8.04 (d, J = 6.6 Hz, 2H), 7.59 (dd, J = 8.6, 7.0 Hz, 1H), 7.23 (d, J = 4.9 Hz, 1H), 7.11 (d, J = 8.6 Hz, 1H), 7.03 (d, J = 7.0 Hz, 1H), 6.54 (t, J = 6.0 Hz, 1H), 5.06 (dd, J = 12.7, 5.5 Hz, 1H), 4.16 (s, 1H), 3.67 (dd, J = 7.1, 3.7 Hz, 4H), 3.57 (d, J = 5.5 Hz, 2H), 3.31 (q, J = 6.4 Hz, 2H), 2.89 (ddd, J = 16.8, 13.7, 5.4 Hz, 1H), 2.63 - 2.56 (m, 1H), 2.49 (s, 1H), 2.38 (t, J = 7.4 Hz, 2H), 2.08 - 2.01 (m, 1H), 1.59 (t, J = 6.9 Hz, 2H), 1.53 (t, J = 7.2 Hz, 2H), 1.40 - 1.33 (m, 12H). Example 9 [ka] 7-(5-(5-(4-(6-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)hexanoyl)piperazin-1-yl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile

[0415] The title compound was synthesized from BB4 and 6-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)hexanoic acid by amide coupling using general method A. LCMS: C 41 H 42 N 12 05S theoretical value: 814.3, measured value: m / z = 817.7 [M+H] + ; 1 H NMR (500 MHz, DMSO-d6) δ 11.10 (s, 1H), 9.26 (s, 1H), 8.95 (d, J = 2.3 Hz, 1H), 8.82 (d, J = 2.3 Hz, 1H), 8.56 (s, 1H), 8.08 (s, 1H), 8.01 (d, J = 4.9 Hz, 1H), 7.63 - 7.56 (m, 1H), 7.21 (d, J = 4.9 Hz, 1H), 7.12 (d, J = 8.6 Hz, 1H), 7.02 (d, J = 7.0 Hz, 1H), 6.55 (t, J = 6.2 Hz, 1H), 5.06 (dd, J = 12.8, 5.4 Hz, 1H), 4.12 (s, 1H), 3.67 (dd, J = 6.9, 3.7 Hz, 4H), 3.56 (d, J = 5.4 Hz, 2H), 3.32 (q, J = 6.6 Hz, 2H), 2.90 (ddd, J = 16.8, 13.8, 5.4 Hz, 1H), 2.65 - 2.56 (m, 1H), 2.41 (t, J = 7.4 Hz, 2H), 2.07 - 2.01 (m, 1H), 1.60 (dp, J = 15.1, 7.3 Hz, 4H), 1.38 (d, J = 6.4 Hz, 8H). Example 10 [ka]

[0416] 7-(5-(5-(4-(3-(2-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)amino)ethoxy)propanoyl)piperazin-1-yl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile

[0417] The title compound was synthesized from BB4 and 3-(2-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)amino)ethoxy)propanoic acid by amide coupling using general method A. LCMS: C 40 H 40 N 12 06S Theoretical value: 816.3, Measured value: m / z = 817.6 [M+H] + ; 1 H NMR (500 MHz, DMSO-d6) δ 11.05 (s, 1H), 9.43 (s, 1H), 8.97 (d, J = 2.2 Hz, 1H), 8.84 (d, J = 2.2 Hz, 1H), 8.54 (s, 1H), 8.07 - 8.02 (m, 2H), 7.54 (d, J = 8.4 Hz, 1H), 7.23 (d, J = 4.9 Hz, 1H), 7.15 (s, 1H), 7.01 (d, J = 2.2 Hz, 1H), 6.90 (dd, J = 8.4, 2.2 Hz, 1H), 5.01 (dd, J = 12.9, 5.4 Hz, 1H), 4.16 (q, J = 6.6 Hz, 1H), 3.76 - 3.58 (m, 8H), 3.57 (s, 2H), 3.36 (t, J = 5.4 Hz, 2H), 2.85 (ddd, J = 17.4, 14.0, 5.5 Hz, 1H), 2.68 (t, J = 6.4 Hz, 2H), 2.58 - 2.53 (m, 1H), 2.50 - 2.43 (m, 0H), 1.97 (dtd, J = 13.0, 6.1, 2.9 Hz, 1H), 1.38 (d, J = 6.3 Hz, 6H). Example 11 [ka]

[0418] 7-(5-(5-(4-(3-(2-(2-(2-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)ethoxy)ethoxy)ethoxy)propanoyl)piperazin-1-yl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile

[0419] The title compound was synthesized from BB4 and 3-(2-(2-(2-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-4-yl)amino)ethoxy)ethoxy)ethoxy)propanoic acid by amide coupling using general method A. LCMS: C 44 H 48 N 12 O8S Theoretical value: 904.3, Measured value: m / z = 906.1 [M+H] + ; 1H NMR (500 MHz, DMSO-d6) δ 11.10 (s, 1H), 8.96 (d, J = 2.1 Hz, 1H), 8.83 (d, J = 2.2 Hz, 1H), 8.53 (s, 1H), 8.07 - 8.00 (m, 2H), 7.56 (t, J = 7.8 Hz, 1H), 7.22 (d, J = 4.9 Hz, 1H), 7.13 (d, J = 8.6 Hz, 1H), 7.01 (d, J = 7.0 Hz, 1H), 6.59 (t, J = 5.7 Hz, 1H), 5.06 (dd, J = 12.7, 5.4 Hz, 1H), 4.13 (s, 1H), 3.65 (dp, J = 17.0, 5.3 Hz, 10H), 3.59 - 3.46 (m, 10H), 3.46 (d, J = 5.6 Hz, 2H), 2.89 (ddd, J = 17.5, 13.8, 5.3 Hz, 1H), 2.67 - 2.56 (m, 3H), 2.05 (dd, J = 9.9, 4.4 Hz, 1H), 1.37 (d, J = 6.3 Hz, 6H). Example 12 [ka]

[0420] 7-(5-(5-(4-(1-(((3R)-1-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)pyrrolidin-3-yl)methyl)piperidine-4-carbonyl)piperazin-1-yl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile

[0421] The title compound was synthesized from BB5 and (3S)-1-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)pyrrolidine-3-carbaldehyde by reductive amination using general method B. LCMS: C 46 H 49 N13 05S theoretical value: 895.4, measured value: m / z = 896.8 [M+H] + ; 1 H NMR (500 MHz, DMSO-d6) δ 11.09 (s, 1H), 9.28 (s, 1H), 9.13 (s, 2H), 8.94 (d, J = 2.3 Hz, 1H), 8.81 (d, J = 2.2 Hz, 1H), 8.58 (s, 1H), 8.11 (s, 1H), 7.99 (d, J = 4.8 Hz, 1H), 7.74 - 7.68 (m, 1H), 7.21 (d, J = 4.9 Hz, 1H), 6.96 (d, J = 2.2 Hz, 1H), 6.85 (dd, J = 8.5, 2.2 Hz, 1H), 5.08 (dd, J = 12.8, 5.4 Hz, 1H), 4.10 (s, 1H), 3.98 (s, 3H), 3.77 (s, 2H), 3.61 - 3.56 (m, 4H), 3.43 (q, J = 8.5 Hz, 1H), 3.27 (dt, J = 27.8, 7.7 Hz, 2H), 3.04 (s, 2H), 3.01 (s, 1H), 2.92 - 2.83 (m, 2H), 2.64 - 2.57 (m, 1H), 2.28 (s, 1H), 2.03 (d, J = 12.1 Hz, 1H), 1.93 (s, 5H), 1.85 (dd, J = 12.2, 8.7 Hz, 1H), 1.38 (d, J = 6.3 Hz, 7H). Example 13 [ka]

[0422] 7-(5-(5-(4-(1-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)methyl)piperidine-4-carbonyl)piperazin-1-yl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile

[0423] 2-(2,6-Dioxopiperidin-3-yl)-1,3-dioxoisoindole-5-carbaldehyde (15 mg, 0.05 mmol), 7-[4-(isopropylamino)-5-{5-[4-(piperidine-4-carbonyl)piperazin-1-yl]-1,3,4-thiadiazol-2-yl}pyridin-2-yl]pyrrolo[1,2-b]pyridazine-3-carbonitrile (BB5, 29 mg, 0.05 mmol) was dissolved in DCE (0.1 M) and triethylamine (0.01 M) and stirred for 10 minutes, after which sodium triacetoxyborohydride (20 mg, 0.1 mmol) was added. The reaction was stirred at room temperature for 2 hours and then partitioned between DCM and water. The organic layer was separated, dried over magnesium sulfate, and purified by HPLC to give 7-(5-{5-[4-(1-{[2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindol-5-yl]methyl}piperidine-4-carbonyl)piperazin-1-yl]-1,3,4-thiadiazol-2-yl}-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile (0.007 g, 16%). LCMS: C 42 H 42 N 12 05S Theoretical value: 826.9, Measured value: m / z = 827.9 [M+H] + ; 1H NMR (500 MHz, DMSO-d6) δ 11.17 (s, 1H), 9.71 (s, 1H), 8.95 (s, 1H), 8.82 (s, 1H), 8.57 (s, 1H), 8.17 (s, 1H), 8.10 (d, J = 6.4 Hz, 2H), 8.03 (dd, J = 22.0, 14.0 Hz, 2H), 7.21 (d, J = 4.8 Hz, 1H), 5.21 (dd, J = 12.8, 5.4 Hz, 1H), 4.55 (s, 2H), 4.11 (s, 2H), 3.73 (s, 14H), 2.96 (d, J = 37.5 Hz, 4H), 2.64 (d, J = 16.2 Hz, 2H), 2.10 (s, 2H), 1.98 - 1.67 (m, 4H), 1.37 (d, J = 6.2 Hz, 7H), 1.34 - 1.21 (m, 1H). Example 14 [ka]

[0424] 7-(5-(5-(4-(3-(4-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)piperazin-1-yl)propanoyl)piperazin-1-yl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile

[0425] The title compound was synthesized from BB4 and 3-(4-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)piperazin-1-yl)propanoic acid by amide coupling using general method A. LCMS: C 42 H 43 N 13 05S Theoretical value: 841.3, Measured value: m / z = 842.8 [M+H] + . Example 15 [ka]

[0426] 7-(5-(5-(4-(2-(2-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)-2,7-diazaspiro[3.5]nonan-7-yl)acetyl)piperazin-1-yl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile

[0427] The title compound was synthesized from BB4 and 2-(2-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)-2,7-diazaspiro[3.5]nonan-7-yl)acetic acid by amide coupling using general method A. LCMS: C 44 H 45 N 13 05S Theoretical value: 867.3, Measured value: m / z = 868.8 [M+H] + . Example 16 [ka]

[0428] 7-(5-(5-(4-(2-(1-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)piperidin-4-yl)ethyl)piperazin-1-yl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile

[0429] The title compound was synthesized from BB4 and 2-(1-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)piperidin-4-yl)acetaldehyde by reductive amination using general method B. LCMS: C 42 H 44 N 12 04S theoretical value: 812.3, measured value: m / z = 814.0 [M+H]+ . Example 17 [ka]

[0430] 7-(5-(5-(4-(1-(((3R)-1-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)pyrrolidin-3-yl)methyl)piperidin-4-yl)piperazin-1-yl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile

[0431] The title compound was synthesized from BB6 and (3S)-1-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)pyrrolidine-3-carbaldehyde by reductive amination using general method B. LCMS: C 45 H 49 N 13 04S theoretical value: 867.4, measured value: m / z = 868.9 [M+H] + . Example 18 [ka]

[0432] 7-(5-(5-(4-(1-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)methyl)piperidin-4-yl)piperazin-1-yl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile

[0433] The title compound was synthesized from BB6 and 2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindoline-5-carbaldehyde by reductive amination using general method B. LCMS: C 41 H 42 N12 04S theoretical value: 798.3, measured value: m / z = 799.8 [M+H] + . Example 19 [ka]

[0434] 77-(5-(5-(4-(((3R)-1-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)pyrrolidin-3-yl)methyl)piperazin-1-yl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile

[0435] The title compound was synthesized from BB4 and (3S)-1-(2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)pyrrolidine-3-carbaldehyde by reductive amination using general method B. LCMS: C 40 H 40 N 12 04S theoretical value: 784.3, measured value: m / z = 785.9 [M+H] + ; 1H NMR (500 MHz, DMSO-d6) δ 11.08 (s, 1H), 9.88 (s, 1H), 8.93 (d, J = 2.3 Hz, 1H), 8.80 (d, J = 2.3 Hz, 1H), 8.58 (s, 1H), 8.14 (s, 1H), 7.97 (s, 1H), 7.71 (d, J = 8.2 Hz, 1H), 7.19 (d, J = 4.9 Hz, 1H), 6.97 (d, J = 2.3 Hz, 1H), 6.86 (dd, J = 8.6, 2.2 Hz, 1H), 6.54 (s, 1H), 5.07 (dd, J = 12.8, 5.4 Hz, 1H), 4.15 (s, 3H), 4.08 (s, 2H), 3.76 (s, 3H), 3.66 (s, 4H), 3.58 (s, 1H), 3.46 (t, J = 8.8 Hz, 1H), 2.87 (s, 2H), 2.62 (s, 1H), 2.60 - 2.53 (m, 1H), 2.29 (s, 1H), 2.04 (s, 1H), 1.86 (t, J = 10.3 Hz, 1H), 1.37 (d, J = 6.3 Hz, 7H). Example 20 [ka] 7-(5-(5-(4-((2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindolin-5-yl)methyl)piperazin-1-yl)-1,3,4-thiadiazol-2-yl)-4-(isopropylamino)pyridin-2-yl)pyrrolo[1,2-b]pyridazine-3-carbonitrile

[0436] The title compound was synthesized from BB4 and 2-(2,6-dioxopiperidin-3-yl)-1,3-dioxoisoindoline-5-carbaldehyde by r...

Claims

【Request Item 1】 【Chemistry 451-1】 【Chemistry 451-2】 【Chemistry 451-3】 【Chemistry 451-4】 【Chemistry 451-5】 【Chemistry 451-6】 【Chemistry 451-7】 【Chemistry 451-8】 【Chemistry 451-9】 【Chemistry 451-10】 【Chemistry 451-11】 【Chemistry 451-12】 【Chemistry 451-13】 【Chemistry 451-14】 【Chemistry 451-15】 【Chemistry 451-16】 【Chemistry 451-17】 【Chemistry 451-18】 【Chemistry 451-19】 【Chemistry 451-20】 【Chemistry 451-21】 【Chemistry 451-22】 【Chemistry 451-23】 【Chemistry 451-24】 【Chemistry 451-25】 【Chemistry 451-26】 【Chemistry 451-27】 【Chemistry 451-28】 A compound having the structure:

2. 10. A pharmaceutical composition comprising a compound of claim 1 and a pharmaceutically acceptable carrier.

3. 10. A composition comprising a compound according to claim 1 or a pharmaceutical composition according to claim 2 for use in the treatment of cancer.

4. 4. The composition of claim 3, wherein the cancer is lymphoma, leukemia, acute myeloid leukemia (AML), and myelodysplastic syndrome (MDS).

5. 10. A composition comprising a compound according to claim 1 or a pharmaceutical composition according to claim 2 for use in the treatment of a metabolic disorder.

6. 6. The composition of claim 5, wherein the metabolic disorder is diabetes (type I and type II diabetes), metabolic syndrome, dyslipidemia, obesity, glucose intolerance, hypertension, elevated serum cholesterol and elevated triglycerides.

7. 10. A composition comprising a compound according to claim 1 or a pharmaceutical composition according to claim 2 for use in the treatment of an inflammatory disorder.

8. 8. The composition of claim 7, wherein the inflammatory disorder comprises rheumatoid arthritis (RA), inflammatory bowel disease (IBD), Crohn's disease, ulcerative colitis, necrotizing enterocolitis, gout, Lyme disease, arthritis, psoriasis, pelvic inflammatory disease, systemic lupus erythematosus (SLE), Sjogren's syndrome, inflammation associated with gastrointestinal infections including C. difficile, viral myocarditis, acute and chronic tissue injury, nonalcoholic steatohepatitis (NASH), alcoholic hepatitis, and kidney disease including chronic kidney disease and diabetic kidney disease.

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