Compounds and uses

Abstract

There is provided herein compound of formula (I) as defined in Formula (I), wherein Ra, Rb, Rc, A and p have meanings given in the description, and pharmaceutically-acceptable salts and solvates thereof, which compounds are useful in the treatment of diseases in which pan-immunoproteasome inhibition is desired or required, and particularly in the treatment of cancer.

Description

[0001] COMPOUNDS AND USES

[0002] Field of the Invention

[0003] The present invention relates to novel compounds, compositions comprising such compounds, and the use of such compounds and compositions in medicine. In particular, the present invention relates to the use of such compounds and compositions in methods for the treatment or prevention of a disease or condition in which pan-immunoproteasome inhibition is desired or required, such as proliferative diseases and auto-immune diseases.

[0004] Background of the Invention

[0005] Proteasomes are vital for maintaining protein homeostasis and involved in various key cellular processes, including cell division, cell signalling and antigen processing (Coux, O.; Tanaka, K.; Goldberg, A. L., Structure and functions of the 20S and 26S proteasomes. Annu. Rev. Biochem. 1996, 65, 801-47). The predominant proteasome types in mammals are the constitutive proteasome, present in all body cells, and the immunoproteasome, mainly expressed by cells of hematopoietic origin (Kniepert, A.; Groettrup, M., The unique functions of tissue-specific proteasomes. Trends in biochemical sciences 2014, 39 (1), 17-24.). Both constitutive and immunoproteasomes feature a 20S core particle (CP; cCP for constitutive proteasomes and iCP for immunoproteasomes) composed of 14 a-type and 14 p-type subunit proteins arranged in a CH-7P1-7P1-7C11-7 manner to form a hollow cylinder. The pi, P2 and P5 subunits are proteolytically active and hydrolyze polypeptides fed into the CP barrel to oligopeptides of eight to ten amino acids. The main difference between cCP and iCP in terms of structure are the catalytic active sites and their substrate binding channels. The cCP incorporates pic (caspase-like activity (C-L)), P2c (trypsin-like activity (T-L)) and P5c (chymotrypsin / elastase-like (ChT-L activity)) subunits that are replaced by pii (ChT-L), p2i (T-L) and p5i (ChT-L) in the iCP.

[0006] Proteasome inhibition studies started in the early 1990s and culminated in the approval of the drugs bortezomib (2003), carfilzomib (2012) and ixazomib (2015) for the treatment of multiple myeloma (Manasanch, E. E.; Orlowski, R. Z., Proteasome inhibitors in cancer therapy. Nat Rev Clin Oncol 2017, 14 (7), 417-433.). These compounds primarily target P5c and P5i of cCP and iCP, respectively. Yet depending on the dose, other catalytic activities can be co-inhibited as well. The constitutive proteasome is found in all healthy tissue and is classified as an off target when viewing proteasome inhibition in a clinical setting. To minimize side effects, to reduce cytotoxicity and to explore potential anti-inflammatory applications, selective inhibition of the immunoproteasome has been sought over the last 10 years. However, it became apparent that co-inhibition of several subunits is required for therapeutically relevant effects (Johnson, H. W. B.; et al., Required Immuno-proteasome Subunit Inhibition Profile for Anti-Inflammatory Efficacy and Clinical Candidate KZR-616 ((2 S,3 R)-N-(( S)-3-(Cyclo-pent-l-en-l-yl)-l-((R)-2-methyl-oxiran-2-yl)-l-oxo-propan-2-yl)-3- hydroxy-3-(4-methoxy-phenyl)-2-((S)-2-(2-morpholino-acetamido) propana mido)- propenamide). J Med Chem 2018, 61 (24), 11127-11143.).

[0007] The proteasome inhibitors, Carfilzomib and Bortezomib, have also been shown to induce resistance pathways thereby rendering proteasome inhibition useless as a treatment in these haematological cancers. One possible way to overcome the resistance observed in haematological cancers and cytotoxicity caused by constitutive proteasome inhibition is to develop proteasome inhibitors that exclusively inhibit the immunoproteasome, a pan-immuno proteasome inhibitor.

[0008] Although compounds that target at least two immuno-subunits with good affinity have already been reported (ONX 0914 (Muchamuel, T.; et al., A selective inhibitor of the immunoproteasome subunit LMP7 blocks cytokine production and attenuates progression of experimental arthritis. Nat. Med. 2009, 15 (7), 781-7), KZR-616 (Johnson, H. W. B.; et al., ibid.') and LU-005i (see below)), a true pan- immunoproteasome inhibitor blocking all three immuno-subunits with equally high potency and leaving the c-subunits untouched is still missing.

[0009] LU-0051

[0010] It has now surprisingly been found that certain compounds are able to act as inhibitors of the immunoproteasome, particularly pan-immunoproteasome inhibitors, which might be useful for the treatment or prevention of a disease or condition in which pan- immunoproteasome inhibition is desired or required, such as proliferative diseases and auto-immune diseases. The listing or discussion of an apparently prior-published document in this specification should not necessarily be taken as an acknowledgement that the document is part of the state of the art or is common general knowledge.

[0011] Description of the Invention

[0012] In a first aspect of the invention, there is provided a compound of formula (I), wherein: one of Raand Rbrepresents H, and the other represents -[CH2]m-X;

[0013] X represents -OC(O)-Y, -C(O)-Y, -OH or OY;

[0014] Y represents -Ci-6 alkyl (optionally substituted by -Zx-Z2) or -CH(Ry)-(Z1-Z2)n;

[0015] Ryrepresents methylbiphenyl or a side chain of a proteinogenic amino acid, optionally wherein the side chain is in a chemically protected form; each Z1is independently -NH-, -N(RZ)- or -O-;

[0016] Rz, if present, is bound to Ryto form a proline ring; each Z2is independently H, -C(O)-Ci-4 alkyl, -C(O)O-Ci-4 alkyl or -Si(Ci-4 alkyl)s; m is 0, 1 or 2; n is 1 or 2; p is 0 or 1; Rcrepresents H or -Ci-4 alkyl optionally substituted with one or more Q substituents;

[0017] Q represents -ORd, -NHReor -C(O)NHRf;

[0018] Rd, Reand Rfrepresent H, -Ci-4 alkyl (optionally substituted with phenyl or methylphenyl), -C(O)-Ci-4 alkyl, -C(O)O-Ci-4 alkyl, -C(O)-Ci-4 alkenyl, -C(O)O-Ci-4 alkenyl, -C( = N)-NHz, -C( = N)-NH-(protecting group), or pyrimidinyl;

[0019] A represents a cyclic moiety selected from the group consisting of:

[0020] Rhrepresents H, Ci-4 alkyl or -C(O)O-Ci-4 alkyl;

[0021] R' represents H, Ci-4 alkyl, -N(Rj)(Rk) or -OH;

[0022] Rjand Rkindependently represent H or Ci-4 alkyl; or a pharmaceutically acceptable salt or solvate thereof.

[0023] Compounds of formula (I), including pharmaceutically acceptable salts and solvates thereof, are referred to herein as the "compounds of the invention".

[0024] For the avoidance of doubt, the skilled person will understand that references herein to compounds of particular aspects of the invention (such as the first aspect of the invention, i.e. referring to compounds of formula (I) as defined in the first aspect of the invention) will include references to all embodiments and particular features thereof, which embodiments and particular features may be taken in combination to form further embodiments and features of the invention.

[0025] Pharmaceutically acceptable salts include acid addition salts and base salts. Such salts may be formed by conventional means, for example by reaction of a free acid or a free base form of a compound of the invention with one or more equivalents of an appropriate acid or base, optionally in a solvent, or in a medium in which the salt is insoluble, followed by removal of said solvent, or said medium, using standard techniques (e.g. in vacuo, by freeze-drying or by filtration). Salts may also be prepared using techniques known to those skilled in the art, such as by exchanging a counterion of a compound of the invention in the form of a salt with another counter-ion, for example using a suitable ion exchange resin.

[0026] Particular acid addition salts that may be mentioned include carboxylate salts (e.g. formate, acetate, trifluoroacetate, propionate, isobutyrate, heptanoate, decanoate, caprate, caprylate, stearate, acrylate, caproate, propiolate, ascorbate, citrate, glucuronate, glutamate, glycolate, gluconate, a-hydroxybutyrate, lactate, tartrate, phenylacetate, mandelate, phenylpropionate, phenylbutyrate, benzoate, chlorobenzoate, methylbenzoate, hydroxybenzoate, methoxybenzoate, dinitrobenzoate, o-acetoxy-benzoate, salicylate, nicotinate, isonicotinate, cinnamate, oxalate, malonate, succinate, suberate, sebacate, fumarate, malate, maleate, hydroxymaleate, hippurate, phthalate or terephthalate salts), halide salts (e.g. chloride, bromide or iodide salts), sulphonate salts (e.g. benzenesulphonate, methyl-, bromo- or chloro-benzenesulphonate, xylenesulphonate, methanesulphonate, ethanesulphonate, propanesulphonate, hydroxy-ethanesulphonate, 1- or 2- naphthalene-sulphonate or 1,5-naphthalene-disulphonate salts) or sulphate, pyrosulphate, bisulphate, sulphite, bisulphite, phosphate, monohydrogenphosphate, dihydrogenphosphate, metaphosphate, pyrophosphate or nitrate salts, and the like.

[0027] Particular base salts that may be mentioned include salts formed with alkali metals (such as Na and K salts), alkaline earth metals (such as Mg and Ca salts), organic bases (such as dicyclohexylamine, ethanolamine, diethanolamine, triethanolamine, tromethamine and lysine) and inorganic bases (such as ammonia and aluminium hydroxide). More particularly, base addition salts that may be mentioned include Mg, Ca and, most particularly, K and Na salts.

[0028] More particular salts that may be mentioned include trifluoroacetate and dicyclohexylamine salts.

[0029] For the avoidance of doubt, compounds of the invention may exist as solids, and thus the scope of the invention includes all amorphous, crystalline and part crystalline forms thereof, and may also exist as oils. Where compounds of the invention exist in crystalline and part crystalline forms, such forms may include solvates, which are included in the scope of the invention. By "solvate" we mean a solid form wherein the relevant compound (e.g. a compound of formula (I)) is associated with one or more solvent molecules. The term solvate includes hydrates and other solvates of pharmaceutically acceptable solvents. Preferred solvents for solvate formation are water and DMSO.

[0030] For the avoidance of doubt, compounds of the invention may also exist in solution (i.e. in solution in a suitable solvent). For example, compounds of the invention may exist in aqueous solution, in which case compounds of the invention may exist in the form of hydrates thereof.

[0031] Compounds of the invention may contain double bonds and, unless otherwise indicated, may thus exist as E (entgeger ) and Z (zusammen) geometric isomers about each individual double bond. Unless otherwise specified, all such isomers and mixtures thereof are included within the scope of the invention.

[0032] Compounds of the invention may also exhibit tautomerism. All tautomeric forms and mixtures thereof are included within the scope of the invention (particularly those of sufficient stability to allow for isolation thereof).

[0033] By "amino acid" and "residue" (for example phenylalanine "residue") we mean the dehydrated portion of an amino acid present in polypeptide chains and represented by the following formula

[0034] S. C. wherein S. C. represents an amino acid side chain. For the avoidance of doubt, the term "amino acid" includes non-proteinogenic amino acids unless otherwise specified.

[0035] By "amino acid side chain" or"side chain of an amino acid" we mean the group attached to the position a to the carboxyl and amino groups in a-amino acids, including non- proteinogenic a-amino acids and particularly proteinogenic amino acids. The skilled person will understand that the most common natural amino acids are known by their trivial names and will be aware of the side chain groups present in these amino acids.

[0036] "Proteinogenic" amino acids are the 22 amino acids that may be naturally encoded or naturally found in the genetic code of organisms. "Non-proteinogenic" amino acids are those not naturally encoded or found in the genetic code of any organism. The set of non-proteinogenic amino acids is generally considered to include all organic compounds with an amine (-NH2) and a carboxylic acid (-COOH) functional group linked via a single additional carbon atom, as well as a side chain and a hydrogen bound to that single additional carbon atom, but excluding selenocysteine, pyrrolysine and the 20 standard amino acids that are incorporated into proteins during translation. Non-proteinogenic amino acids include those amino acids that are intermediates in biosynthesis, those that are post-translationally formed in proteins, and those that possess a physiological role (e.g. components of bacterial cell walls, neurotransmitters, and toxins).

[0037] Compounds of the invention contain at least one asymmetric carbon atom and may therefore exhibit optical and / or diastereoisomerism (i.e. existing in enantiomeric or diastereomeric forms). Diastereoisomers may be separated using conventional techniques, e.g. chromatography or fractional crystallisation. The various stereoisomers (i.e. enantiomers) may be isolated by separation of a racemic or other mixture of the compounds using conventional, e.g. fractional crystallisation or HPLC, techniques. Alternatively the desired enantiomer or diastereoisomer may be obtained from appropriate optically active starting materials under conditions which will not cause racemisation or epimerisation (i.e. a 'chiral pool' method), by reaction of the appropriate starting material with a 'chiral auxiliary' which can subsequently be removed at a suitable stage, by derivatisation (i.e. a resolution, including a dynamic resolution; for example, with a homochiral acid followed by separation of the diastereomeric derivatives by conventional means such as chromatography), or by reaction with an appropriate chiral reagent or chiral catalyst, all of which methods and processes may be performed under conditions known to the skilled person. Unless otherwise specified, all stereoisomers and mixtures thereof are included within the scope of the invention.

[0038] Unless otherwise specified, Ci-Zalkyl groups (where z is the upper limit of the range) defined herein may be straight-chain or, when there is a sufficient number (i.e. a minimum of two or three, as appropriate) of carbon atoms, be branched-chain, and / or cyclic (so forming a C3-Z cycloalkyl group). When there is a sufficient number (i.e. a minimum of four) of carbon atoms, such groups may also be part cyclic (so forming a C4-Z partial cycloalkyl group). For example, cycloalkyl groups that may be mentioned include cyclopropyl, cyclopentyl and cyclohexyl. Similarly, part cyclic alkyl groups (which may also be referred to as "part cycloalkyl" groups) that may be mentioned include cyclopropylmethyl. For the avoidance of doubt, particular alkyl groups that may be mentioned include straight chain (i.e. not branched and / or cyclic) alkyl groups. Unless otherwise specified, C2-Z alkenyl groups (where z is the upper limit of the range) defined herein may be straight-chain or, when there is a sufficient number (i.e. a minimum of three) of carbon atoms, be branched-chain, and / or cyclic (so forming a C4-z cycloalkenyl group). When there is a sufficient number (i.e. a minimum of five) of carbon atoms, such groups may also be part cyclic. For the avoidance of doubt, particular alkenyl groups that may be mentioned include straight chain (i.e. not branched and / or cyclic) alkenyl groups.

[0039] As may be used herein, the term aryl may refer to C6-14 (e.g. Ce-io) aromatic groups. Such groups may be monocyclic or bicyclic and, when bicyclic, be either wholly or partly aromatic. Ce-io aryl groups that may be mentioned include phenyl, naphthyl, 1, 2,3,4- tetrahydronaphthyl, indanyl, and the like (e.g. phenyl, naphthyl, and the like). For the avoidance of doubt, the point of attachment of substituents on aryl groups may be via any suitable carbon atom of the ring system.

[0040] For the avoidance of doubt, the skilled person will understand that aryl groups that may form part of compounds of the invention are those that are chemically obtainable, as known to those skilled in the art. Particular aryl groups that may be mentioned include phenyl and naphthyl, such as phenyl.

[0041] The present invention also embraces isotopically-labelled compounds of the present invention which are identical to those recited herein, but for the fact that one or more atoms are replaced by an atom having an atomic mass or mass number different from the atomic mass or mass number usually found in nature (or the most abundant one found in nature). All isotopes of any particular atom or element as specified herein are contemplated within the scope of the compounds of the invention. Hence, the compounds of the invention also include deuterated compounds, i.e. compounds of the invention in which one or more hydrogen atoms are replaced by the hydrogen isotope deuterium.

[0042] For the avoidance of doubt, in cases in which the identity of two or more substituents in a compound of the invention may be the same, the actual identities of the respective substituents are not in any way interdependent. For example, in the situation in which two or more Z1groups are present, those Z1groups may be the same or different. Similarly, where two or more Z2groups are present and each represents -C(O)-Ci-4 alkyl, the -C(O)-Ci-4 alkyl groups in question may be the same or different. Also for the avoidance of doubt, when a term such as "1 to 4" is employed herein, this will be understood by the skilled person to mean 1, 2, 3 and 4, inclusively. Unless otherwise stated, the same reasoning will apply to other such terms used herein.

[0043] Further for the avoidance of doubt, when it is specified that a substituent is itself optionally substituted by one or more substituents (e.g. Ci-6 alkyl optionally substituted by one or more groups independently selected from -Z1- / 2), these substituents where possible may be positioned on the same or different atoms. Such optional substituents may be present in any suitable number thereof (e.g. the relevant group may be substituted with one or more such substituents, such as one such substituent).

[0044] For the avoidance of doubt, where groups are referred to herein as being optionally substituted it is specifically contemplated that such optional substituents may be not present (i.e. references to such optional substituents may be removed), in which case the optionally substituted group may be referred to as being unsubstituted.

[0045] For the avoidance of doubt, the skilled person will appreciate that compounds of the invention that are the subject of this invention include those that are obtainable, i.e. those that may be prepared in a stable form. That is, compounds of the invention include those that are sufficiently robust to survive isolation, e.g. from a reaction mixture, to a useful degree of purity.

[0046] In compounds of formula (I), the portion of the molecule may be referred to as the Pl' portion (or Pl' region, or similar).

[0047] In particular embodiments (i.e. particular embodiments of the first aspect of the invention), Rbrepresents H. For the avoidance of doubt, Rarepresents -[CFhjm-X in such compounds.

[0048] In another embodiment of the invention, Raor Rb(particularly Ra) represents -[CHzjm- X in which m is 0 or 1. In particular embodiments, m is 0.

[0049] In a further embodiment, X represents -OC(O)-Y, -C(O)-Y or -OY. Most particularly, X may represent -OC(O)-Y. Each of said groups may form part of Raor Rb, but it is preferred that they form part of Ra. It is also preferred that m is 0 for such compounds. In a further embodiment, Y represents -C3-5 alkyl (optionally substituted by -Z’-Z2) or -CHCR -CZ1- / 2)^

[0050] Particular compounds of the invention include those which comprise an amino acid (or a protected derivative thereof) as part of Raor Rb(preferably Ra). Such compounds include those in which X represents -OC(O)-Y, -C(O)-Y or OY, Y represents -CH(Ry)~ (Zx-Z2), and -Z1- represents -NH- or -N(RZ)-. In a particular embodiments therefore, the Raor Rbmoiety may terminate in an amino acid group or a protected derivative thereof. These compounds of formula (I) may alternatively be defined as compounds in which one of Raand Rbrepresents H (preferably Rbis H), and the other represents either -[CH2]m-0-T or -[CH2]m-T, and T represents an amino acid group or a protected derivative thereof bound to the oxygen atom or [CHzJm group via the carbonyl of that amino acid. T may be represented structurally by either -C(O)-CH(Ry)-NH-Z2or -C(O)-CH(Ry)-N(Rz)-Z2. Such compounds in which -Z2is -C(O)O-tert butyl are therefore Boc-protected amino acids. Other protecting groups known to the skilled person for the protection of amines may alternatively be used at -Z2, such as carbobenzyloxy (Cbz), 9-fluorenylmethyloxycarbonyl (Fmoc), acetyl (Ac), benzoyl (Bzl) and benzyl (Bn).

[0051] Ryrepresents methylbiphenyl or a side chain of a proteinogenic amino acid, optionally wherein the side chain is in a chemically protected form. Amino acid side chains that contain a primary amine or amide functional group (e.g. the side chain of lysine) may be protected using any one of Boc, Cbz, Fmoc, Ac, Bzl and Bn, or any other suitable protecting group known to the skilled person such as allyloxycarbonyl (Alloc). Side chains that contain a carboxylate group (e.g. the side chain of aspartic acid or glutamic acid) may be protected by conversion into an ester (e.g. Bn ester, a trityl (Trt) ester, a C1-6 alkyl ester, a fluorenylmethyl (Fm) ester or a silyl ester) or with any other suitable protecting group known to the skilled person. Side chains that contain an alcohol functional group (e.g. the side chain of serine or threonine) may be protected using any one of a C1-4 alkyl ether, Bn, Ac, Bzl, triphenylmethyl (Trt), Tetrahydropyranyl (Thp) and a silyl ether (such as trimethylsilyl (TMS), triisopropylsilyl (TIPS) and tert-butyldimethylsilyl (TBDMS)), or any other suitable protecting group known to the skilled person. Side chains that contain a thiol functional group (e.g. the side chain of cysteine) may be protected using any one of Trt, Bn, and tert-butyl, or any other suitable protecting group known to the skilled person. Side chains that contain a guanidine / guanidinium functional group (e.g. the side chain of arginine) may be protected using any one of Cbz and 2,2,4,6,7-pentamethyl-2,3-dihydrobenzofuran- 5-sulfonyl (Pbf), or any other suitable protecting group known to the skilled person. In a particular embodiment, Ryrepresents methylbiphenyl (the BipA side chain), a side chain of a proteinogenic amino acid or a chemically protected form of a side chain of a proteinogenic amino acid, wherein said chemical protection involves attachment of a moiety selected from the group consisting of a benzoyl group, a benzyl group, and a trityl group.

[0052] Preferred compounds of the invention include those in which n is 1. Other preferred compounds include those in which m is 0 or 1, optionally wherein n is 1.

[0053] In compounds of formula (I), the location at which Rcis bound may be referred to as the "P3" position. It has been found that structural variation at the P3 position is generally well tolerated, particularly when the ring at A is relatively small (i.e. it contains few, if any, non-hydrogen substituents). Therefore, in compounds of the invention, Rcmay represent H or -Ci-4 alkyl optionally substituted with one or more Q substituents, where Q represents -ORd, -NHReor -C(O)NHRf, and Rd, Reand Rfrepresent H, -Ci-4 alkyl (optionally substituted with phenyl or methylphenyl), -C(O)-Ci-4alkyl, -C(O)O-Ci-4alkyl, -C(O)-Ci-4alkenyl, -C(O)O-Ci-4alkenyl, -C( = N)-NH2, -C( = N)-NH-(protecting group), or pyrimidinyl. Protecting groups of the sort described above in respect of the Pl' position are equally applicable to the P3 position. This particularly includes Cbz and Pbf when Q represents a guanidinyl group.

[0054] Particular groups that may be mentioned in respect of Rcinclude those which are hydrogen bond acceptors (e.g. they include an N or O atom having at least one lone pair). In one embodiment, Q represents -NHz, -NH-C(O)-CH3, -NH(Alloc), -NH-C( = N)- NHz, -NH-C( = N)-NH-(protecting group), -C(O)-NHz, -OH, -O-benzyl, -O-xylyl, or -NH(pyrimidinyl).

[0055] Further particular groups that may be mentioned in respect of Rcare side chains of proteinogenic amino acids, as well protected derivatives of those side chains. Side chains, or protected derivatives thereof, that contain at least one hydrogen bond acceptor, have been shown to be particularly effective, with oxygen-containing side chains (and protected derivatives thereof) showing the greatest efficacy. Therefore, in another embodiment, Rcrepresents -C1-3 alkyl substituted with one Q substituent, where Q is selected from the group consisting of -OH and -O-C1-4 alkyl (optionally substituted with phenyl or methylphenyl). Compounds that have been shown to be especially effective as pan- immunoproteasome inhibitors include those in which Rcrepresents the side chain of serine or a protected derivative thereof. Protected derivatives of serine that may be mentioned in this context include serine protected with Bn, ethyl or propyl, and the pan-immunoproteasome efficacy of compounds containing a protected serine at P3 has been found to be enhanced when this is combined with a ring lacking any bulky side chains at the A position (i.e. Rhor R' represent H, -OH or -CH3).

[0056] Compounds of the invention in which Rcrepresents methyl have also been found to be effective as pan-immunoproteasome inhibitors.

[0057] In compounds of formula (I), the location at which ring A is bound may be referred to as the "P4" position. Compounds in which ring A contain a Boc substituent have been shown to have a high likelihood of enhanced pan-immunoproteasome activity. Without wishing to be bound by theory, it is believed that a substituent containing a tert-butyl group will show similar potential due to its bulky and hydrophobic characteristics enabling the substituent to undergo hydrophobic interactions at the target site, particularly if that substituent is located on the 4-position of the six-membered ring denoted by A in formula (I).

[0058] In other embodiments, such as when Rcrepresents a protected amino acid side chain, ring A lacks any bulky side chains (i.e. Rhand R' represent H, -OH or -CH3).

[0059] Particular A groups that may be mentioned are therefore morpholinyl, 4-methylpiperidinyl, 4-(t-butyloxycarbonyl)-piperidinyl, piperidinyl, and 4-hydroxy- cyclohexyl. In one embodiment, A represents a morpholinyl group.

[0060] The carbon atom to which Rcis bound is a chiral centre. Compounds of the invention may have either the D- or L-configuration at this position, or may relate to a mixture of both configurations at this position. Compounds of formula (I) in which the P3 region corresponds to a D-amino acid are believed to have particularly enhanced P5i selectivity.

[0061] Compounds of the invention contain other chiral centres, including the point of attachment of the mandatory cyclohexylmethyl group (the "Pl" position) and the mandatory O-methyl tyrosine side chain (the "P2" position). Thus, the Pl and P2 regions represent covalently linked amino acids. Compounds of the invention may have either the D- or L-configuration independently at each position, or may relate to a mixture of both configurations at each position.

[0062] It is preferred that the Pl and P2 regions both have a L-configuration. References to "L-configuration" here and elsewhere include that the product has a substantial absence of compounds bearing one or more the D-configurations at these regions (and vice versa). The skilled person will know that absolute purity in this respect is not possible. The invention therefore relates to compounds that, in respect of any given chiral centre, have an enantiomeric excess of at least 50%, preferably at least 80%, such as at least 90% of the desired enantiomer.

[0063] Particular compounds of the invention that may be mentioned include those compounds as described in the examples provided herein, and pharmaceutically acceptable salts thereof. Thus, particular compounds of the invention that may be mentioned include: and pharmaceutically acceptable salts thereof.

[0064] Medical uses As indicated herein, the compounds of the invention and compositions comprising the same are useful as pharmaceuticals.

[0065] Thus, according to a second aspect of the invention there is provided a compound of the invention, as hereinbefore defined (i.e. a compound as defined in the first aspect of the invention, including all embodiments and particular features thereof), for use as a pharmaceutical (or for use in medicine).

[0066] For the avoidance of doubt, references to compounds as defined in the first aspect of the invention will include references to compounds of formula (I) (including all embodiments thereof) and pharmaceutically acceptable salts and solvates thereof.

[0067] Although compounds of the invention may possess pharmacological activity as such, certain pharmaceutically-acceptable (e.g. "protected") derivatives of compounds of the invention may exist or be prepared which may not possess such activity, but may be administered parenterally or orally and thereafter be metabolised in the body to form compounds of the invention. Such compounds (which may possess some pharmacological activity, provided that such activity is appreciably lower than that of the active compounds to which they are metabolised) may therefore be described as "prodrugs" of compounds of the invention.

[0068] As used herein, references to prodrugs will include compounds that form a compound of the invention, in an experimentally-detectable amount, within a predetermined time, following enteral or parenteral administration (e.g. oral or parenteral administration). All prodrugs of the compounds of the invention are included within the scope of the invention.

[0069] Furthermore, certain compounds of the invention may possess no or minimal pharmacological activity as such, but may be administered parenterally or orally, and thereafter be metabolised in the body to form compounds of the invention that possess pharmacological activity as such. Such compounds (which also includes compounds that may possess some pharmacological activity, but that activity is appreciably lower than that of the active compounds of the invention to which they are metabolised), may also be described as "prodrugs".

[0070] For the avoidance of doubt, compounds of the invention are therefore useful because they possess pharmacological activity, and / or are metabolised in the body following oral or parenteral administration to form compounds that possess pharmacological activity.

[0071] As described herein, compounds of the invention may be particularly useful in treating and / or preventing a disease or condition in which pan-immunoproteasome inhibition is desired or required. Thus, in a third aspect of the invention, there is provided a compound of the invention, as hereinbefore defined, for use in the treatment or prevention of a disease or condition in which pan-immunoproteasome inhibition is desired or required. Use in treating a disease or condition in which pan- immunoproteasome inhibition is desired or required is particularly preferred.

[0072] In an alternative third aspect of the invention, there is provided a method of treating or preventing a disease or condition in which pan-immunoproteasome inhibition is desired or required comprising administering to a patient in need thereof a therapeutically effective amount of a compound of the invention, as hereinbefore defined.

[0073] In a further alternative third aspect of the invention, there is provided the use of a compound of the invention, as hereinbefore defined, for the manufacture of a medicament for the treatment or prevention of a disease or condition in which pan- immunoproteasome inhibition is desired or required.

[0074] The skilled person will understand that references to the treatment of a particular condition (or, similarly, to treating that condition) will take their normal meanings in the field of medicine. In particular, the terms may refer to achieving a reduction in the severity and / or frequency of occurrence of one or more clinical symptom associated with the condition, as adjudged by a physician attending a patient having or being susceptible to such symptoms. For example, in the case of multiple myeloma, the term may refer to the prolongation of progression-free survival of the patient.

[0075] As used herein, the term prevention (and, similarly, preventing) will include references to the prophylaxis of the disease or disorder (and vice-versa). As such, references to prevention may also be references to prophylaxis, and vice versa. In particular, such terms term may refer to achieving a reduction (for example, at least a 10% reduction, such as at least a 20%, 30% or 40% reduction, e.g. at least a 50% reduction) in the likelihood of the patient (or healthy subject) developing the condition (which may be understood as meaning that the condition of the patient changes such that patient is diagnosed by a physician as having, e.g. requiring treatment for, the relevant disease or disorder).

[0076] As used herein, references to a patient (or to patients) will refer to a living subject being treated, including mammalian (e.g. human) patients. In particular, references to a patient will refer to human patients. For the avoidance of doubt, the compounds of the invention may also be used in the treatment of non-human animals.

[0077] The skilled person will understand that such treatment or prevention will be performed in a patient (or subject) in need thereof. The need of a patient (or subject) for such treatment or prevention may be assessed by those skilled the art using routine techniques. References herein to a patient in need of preventative therapy include references to a patient that is susceptible to a disease or condition in which pan- immunoproteasome inhibition is desired or required, but who is not currently diagnosed with such a disease. As used herein, the terms disease and disorder may be used interchangeably.

[0078] As used herein, the term effective amount will refer to an amount of a compound that confers a therapeutic effect on the treated patient. The effect may be observed in a manner that is objective (i.e. measurable by some test or marker) or subjective (i.e. the subject gives an indication of and / or feels an effect). In particular, the effect may be observed (e.g. measured) in a manner that is objective, using appropriate tests as known to those skilled in the art.

[0079] In particular embodiments (i.e. certain embodiments of the third aspect of the invention), the disease or condition is a haematological malignancy, a solid tumour, an auto-immune disease or an inflammatory disease.

[0080] As described herein, the compounds of the first aspect of the invention may find particular utility in a haematological malignancy selected from the group consisting of leukemia, lymphoma, myeloma (including multiple myeloma), myelodysplastic syndrome and myeloproliferative syndrome.

[0081] The skilled person will understand that references to solid cancers that may be treated or prevented using the compounds of the invention include prostate cancer, breast cancer, lung cancer, colon cancer, pancreatic cancer, renal cancer, ovarian cancer, osteosarcoma and colitis-associated cancers.

[0082] Particular inflammatory diseases that may be treated or prevented using a compound of the invention include brain inflammation, viral myocarditis, inflammatory bowel disease, arthritis, polymyositis, dermatomyositis, autoimmune hepatitis, and lupus nephritis.

[0083] Compounds of the invention may also be used in the treatment or prevention of a disease or condition selected from the group consisting of Alzheimer's disease, angiogenesis, acute kidney injury, ischemic stroke, preterm birth, abdominal aortic aneurysm, atherosclerosis, cardiac remodeling, and Graft versus host disease (GvHD).

[0084] Pharmaceutical com As described herein, compounds of the invention are useful as pharmaceuticals. Such compounds may be administered alone or may be administered by way of known pharmaceutical compositions / formulations.

[0085] In a fourth aspect of the invention, there is provided a pharmaceutical composition comprising a compound of the invention as defined herein, and optionally one or more pharmaceutically-acceptable excipient.

[0086] As used herein, the term pharmaceutically-acceptable excipients includes references to vehicles, adjuvants, carriers, diluents, pH adjusting and buffering agents, tonicity adjusting agents, stabilizers, wetting agents and the like. In particular, such excipients may include adjuvants, diluents or carriers.

[0087] For the avoidance of doubt, references herein to compounds of the invention being for particular uses (and, similarly, to uses and methods of use relating to compounds of the invention) may also apply to pharmaceutical compositions comprising compounds of the invention, as described herein.

[0088] Thus, in a fifth aspect of the invention, there is provided a pharmaceutical composition as defined in the fourth aspect of the invention for use in the treatment or prevention of a disease or condition in which pan-immunoproteasome inhibition is desired or required (as defined herein, with reference to the third aspect of the invention and all embodiments thereof).

[0089] The skilled person will understand that compounds of the invention may act systemically and / or locally (i.e. at a particular site), and may therefore be administered accordingly using suitable techniques known to those skilled in the art.

[0090] The skilled person will understand that compounds and compositions as described herein will normally be administered orally, intravenously, subcutaneously, buccally, rectally, dermally, nasally, tracheally, bronchially, sublingually, intranasally, topically, by any other parenteral route or via inhalation, in a pharmaceutically acceptable dosage form.

[0091] Pharmaceutical compositions as described herein will include compositions in the form of tablets, capsules or elixirs for oral administration, suppositories for rectal administration, sterile solutions or suspensions for parenteral or intramuscular administration, and the like. Alternatively, particularly where such compounds of the invention act locally, pharmaceutical compositions may be formulated for topical administration.

[0092] Thus, in particular embodiments, the pharmaceutical formulation is provided in a pharmaceutically acceptable dosage form, including tablets or capsules, liquid forms to be taken orally or by injection, suppositories, creams, gels, foams, inhalants (e.g. to be applied intranasally), or forms suitable for topical administration. For the avoidance of doubt, in such embodiments, compounds of the invention may be present as a solid (e.g. a solid dispersion), liquid (e.g. in solution) or in other forms, such as in the form of micelles.

[0093] For example, in the preparation of pharmaceutical formulations for oral administration, the compound may be mixed with solid, powdered ingredients such as lactose, saccharose, sorbitol, mannitol, starch, amylopectin, cellulose derivatives, gelatin, or another suitable ingredient, as well as with disintegrating agents and lubricating agents such as magnesium stearate, calcium stearate, sodium stearyl fumarate and polyethylene glycol waxes. The mixture may then be processed into granules or compressed into tablets.

[0094] Soft gelatin capsules may be prepared with capsules containing one or more active compounds (e.g. compounds of the first and, therefore, second and third aspects of the invention, and optionally additional therapeutic agents), together with, for example, vegetable oil, fat, or other suitable vehicle for soft gelatin capsules. Similarly, hard gelatine capsules may contain such compound(s) in combination with solid powdered ingredients such as lactose, saccharose, sorbitol, mannitol, potato starch, corn starch, amylopectin, cellulose derivatives or gelatin.

[0095] Dosage units for rectal administration may be prepared (i) in the form of suppositories which contain the compound(s) mixed with a neutral fat base; (ii) in the form of a gelatin rectal capsule which contains the active substance in a mixture with a vegetable oil, paraffin oil, or other suitable vehicle for gelatin rectal capsules; (iii) in the form of a ready-made micro enema; or (iv) in the form of a dry micro enema formulation to be reconstituted in a suitable solvent just prior to administration.

[0096] Liquid preparations for oral administration may be prepared in the form of syrups or suspensions, e.g. solutions or suspensions, containing the compound(s) and the remainder of the formulation consisting of sugar or sugar alcohols, and a mixture of ethanol, water, glycerol, propylene glycol and polyethylene glycol. If desired, such liquid preparations may contain colouring agents, flavouring agents, saccharine and carboxymethyl cellulose or other thickening agent. Liquid preparations for oral administration may also be prepared in the form of a dry powder to be reconstituted with a suitable solvent prior to use.

[0097] Solutions for parenteral administration may be prepared as a solution of the compound(s) in a pharmaceutically acceptable solvent. These solutions may also contain stabilizing ingredients and / or buffering ingredients and are dispensed into unit doses in the form of ampoules or vials. Solutions for parenteral administration may also be prepared as a dry preparation to be reconstituted with a suitable solvent extemporaneously before use.

[0098] Depending on e.g. potency and physical characteristics of the compound of the invention (i.e. active ingredient), pharmaceutical formulations that may be mentioned include those in which the active ingredient is present in an amount that is at least 1% (or at least 10%, at least 30% or at least 50%) by weight. That is, the ratio of active ingredient to the other components (i.e. the addition of adjuvant, diluent and carrier) of the pharmaceutical composition is at least 1 :99 (or at least 10:90, at least 30:70 or at least 50:50) by weight.

[0099] The skilled person will understand that compounds of the invention may be administered (for example, as formulations as described hereinabove) at varying doses, with suitable doses being readily determined by one of skill in the art. Oral and topical dosages (and subcutaneous dosages, although these dosages may be relatively lower) may range from between about 0.01 pg / kg of body weight per day (pg / kg / day) to about 200 pg / kg / day, preferably about 0.01 to about 10 pg / kg / day, and more preferably about 0.1 to about 5.0 pg / kg / day. For example, when administered orally, treatment with such compounds may comprise administration of a formulations typically containing between about 0.01 pg to about 2000 mg, for example between about 0.1 pg to about 500 mg, or between 1 pg to about 100 mg (e.g. about 20 pg to about 80 mg), of the active ingredient(s). When administered intravenously, the most preferred doses will range from about 0.001 to about 10 pg / kg / hour during constant rate infusion. Advantageously, treatment may comprise administration of such compounds and compositions in a single daily dose, or the total daily dosage may be administered in divided doses of two, three or four times daily (e.g. twice daily with reference to the doses described herein, such as a dose of 5 mg, 10 mg, 25 mg, 50 mg, 100 mg or 200 mg twice daily). When used herein in relation to a specific value (such as an amount), the term "about" (or similar terms, such as "approximately") will be understood as indicating that such values may vary by up to 10% (particularly, up to 5%, such as up to 1%) of the value defined. It is contemplated that, at each instance, such terms may be replaced with the notation "±10%", or the like (or by indicating a variance of a specific amount calculated based on the relevant value). It is also contemplated that, at each instance, such terms may be deleted.

[0100] For the avoidance of doubt, the skilled person (e.g. the physician) will be able to determine the actual dosage which will be most suitable for an individual patient, which is likely to vary with the route of administration, the type and severity of the condition that is to be treated, as well as the species, age, weight, sex, renal function, hepatic function and response of the particular patient to be treated. Although the above- mentioned dosages are exemplary of the average case, there can, of course, be individual instances where higher or lower dosage ranges are merited, and such doses are within the scope of the invention.

[0101] Preparation of compounds / compositions

[0102] Pharmaceutical formulations may be prepared in accordance with standard and / or accepted pharmaceutical practice.

[0103] Thus, in a further aspect of the invention there is provided a process for the preparation of a pharmaceutical formulation, as hereinbefore defined, which process comprises bringing into association a compound of the invention, as hereinbefore defined, with one or more pharmaceutically-acceptable excipient.

[0104] As used herein, references to bringing into association will mean that the two components are rendered suitable for administration in conjunction with each other.

[0105] Compounds of the invention as described herein may be prepared in accordance with techniques that are well known to those skilled in the art, such as those described in the examples provided hereinafter.

[0106] According to a sixth aspect of the invention there is provided a process for the preparation of a compound of the invention as hereinbefore defined, comprising the step of reacting a compound of formula (II),

[0107] wherein A, p and Rcare as hereinbefore defined, with a compound of formula (III) wherein Y is as hereinbefore defined, in the presence of a suitable coupling reagent (e.g. O-(lH-6-Chlorobenzotriazole-l-y I)- 1, 1,3, 3-tetra methyl uronium hexafluorophosphate, l,l'-carbonyldiimidazole, N,N’-dicyclohexylcarbodiimide, or the like) under standard conditions known to those skilled in the art (e.g. optionally in the presence of a suitable solvent, suitable base and / or in an inert atmosphere), for example under reaction conditions known to be used for the Steglich esterification reaction.

[0108] Compounds of formulae (II) and (III) are either commercially available, are known in the literature, or may be obtained either by analogy with the processes described herein, or by conventional synthetic procedures, in accordance with standard techniques, from available starting materials using appropriate reagents and reaction conditions. In this respect, the skilled person may refer to inter alia "Comprehensive Organic Synthesis" by B. M. Trost and I. Fleming, Pergamon Press, 1991. Further references that may be employed include "Heterocyclic Chemistry" by J. A. Joule, K. Mills and G. F. Smith, 3rdedition, published by Chapman & Hall, "Comprehensive Heterocyclic Chemistry II” by A. R. Katritzky, C. W. Rees and E. F. V. Scriven, Pergamon Press, 1996 and "Science of Synthesis" , Volumes 9-17 (Hetarenes and Related Ring Systems), Georg Thieme Verlag, 2006.

[0109] In particular, compounds of formula (III) may be prepared by reaction of a compound of formula (IV), wherein A, p and Rcare as hereinbefore defined, with a compound of formula (V), wherein the compound of formula (IV) is first reacted with hydrazine hydrate to form the peptide hydrazide under suitable conditions as would be known to the skilled person, such as in the presence of a polar solvent, and then further reacted with tertbutylnitrite under suitable conditions, such as at a low temperature in a non-aqueous solvent, before being brought into contact with the compound of formula (V).

[0110] Other specific transformation steps (including those that may be employed in order to form compounds of formula (I)) that may be mentioned include:

[0111] (i) oxidations, for example of a moiety containing an alkene group (e.g. -CH=CH2) to an epoxide, for example in the presence of a suitable oxidising agent, e.g. MnOz or mcpba or the like;

[0112] (ii) formation of an amide, for example by reaction of a acid choride with an amine or by an amide coupling reaction, i.e. the formation of an amide from a carboxylic acid (or ester thereof), for example -C(O)OH (or an ester thereof), may be converted to - C(O)N(R1)R2group (in which R1and R2are hydrogen or a carbon-containing species), and which reaction may (e.g. for -COOH) be performed in the presence of a suitable coupling reagent (e.g. O-(lH-6-Chlorobenzotriazole-l-yl)-l,l,3,3-tetramethyluronium hexafluoro-phosphate, l,l'-carbonyldiimidazole, / V, / V’-dicyclohexylcarbodiimide, or the like) or, in the case of an ester (e.g. -C(O)OCH3 or -C(O)OCH2CH3), be performed in the presence of e.g. trimethylaluminium, or, alternatively the -C(O)OH group may first be activated to the corresponding acyl halide (e.g -C(O)CI, by treatment with oxalyl chloride, thionyl chloride, phosphorous pentachloride, phosphorous oxychloride, or the like), and, in all cases, the relevant compound is reacted with a compound of formula HN(R1)R2(in which R1and R2are as hereinbefore defined), under standard conditions known to those skilled in the art (e.g. optionally in the presence of a suitable solvent, suitable base and / or in an inert atmosphere);

[0113] (iii) transformation of a methoxy group to a hydroxy group, by reaction in the presence of an appropriate reagent, such as boron fluoride-dimethyl sulfide complex or BB (e.g. in the presence of a suitable solvent such as dichloromethane);

[0114] (iv) alkylation or acylation reactions, which may be performed in the presence of base and solvent (such as those described hereinbefore);

[0115] (v) specific deprotection steps, such as deprotection of an / V-Boc protecting group by reaction in the presence of an acid, or, a hydroxy group protected as a silyl ether (e.g. a tert-butyl-dimethylsilyl protecting group) may be deprotected by reaction with a source of fluoride ions, e.g. by employing the reagent tetrabutylammonium fluoride (TBAF).

[0116] Similarly, compounds of formulae (IV) and (V) are either commercially available, are known in the literature, or may be obtained either by analogy with the processes described herein, or by conventional synthetic procedures, in accordance with standard techniques, from available starting materials using appropriate reagents and reaction conditions.

[0117] The skilled person will understand that the substituents as defined herein, and substituents thereon, may be modified one or more times, after or during the processes described above for the preparation of compounds of the invention by way of methods that are well known to those skilled in the art. Examples of such methods include substitutions, reductions, oxidations, dehydrogenations, alkylations, dealkylations, acylations, hydrolyses, esterifications, etherifications, halogenations and nitrations. The precursor groups can be changed to a different such group, or to the groups defined in formula (I), at any time during the reaction sequence. The skilled person may also refer to "Comprehensive Organic Functional Group Transformations" by A. R. Katritzky, O. Meth-Cohn and C. W. Rees, Pergamon Press, 1995 and / or "Comprehensive Organic Transformations" by R. C. Larock, Wiley-VCH, 1999.

[0118] Compounds of the invention may be isolated from their reaction mixtures and, if necessary, purified using conventional techniques as known to those skilled in the art. Thus, processes for preparation of compounds of the invention as described herein may include, as a final step, isolation and optionally purification of the compound of the invention. It will be appreciated by those skilled in the art that, in the processes described above and hereinafter, the functional groups of intermediate compounds may need to be protected by protecting groups. The protection and deprotection of functional groups may take place before or after a reaction in the above-mentioned schemes.

[0119] Protecting groups may be applied and removed in accordance with techniques that are well-known to those skilled in the art and as described hereinafter. For example, protected compounds / intermediates described herein may be converted chemically to unprotected compounds using standard deprotection techniques. The type of chemistry involved will dictate the need, and type, of protecting groups as well as the sequence for accomplishing the synthesis. The use of protecting groups is fully described in "Protective Groups in Organic Synthesis", 3rd edition, T.W. Greene & P.G.M. Wutz, Wiley-Interscience (1999), the contents of which are incorporated herein by reference.

[0120] Without wishing to be bound by theory, it is believed that the compounds of the invention have an iCP-favoured inhibition profile relative to that of LU-005i and so have potential as pan-immunoproteasome selective inhibitors. By exclusively inhibiting the immunoproteasome, the pan-immunoproteasome inhibitors may be able to overcome the resistance observed in haematological cancers and cytotoxicity caused by constitutive proteasome inhibition.

[0121] Compounds of the invention may have the advantage that they may be more efficacious than, be less toxic than, be longer acting than, be more potent than, produce fewer side effects than, be more easily absorbed than, and / or have a better pharmacokinetic profile (e.g. higher oral bioavailability and / or lower clearance) than, and / or have other useful pharmacological, physical, or chemical properties over, compounds known in the prior art, whether for use in the above-stated indications or otherwise. In particular, compounds of the invention may have the advantage that they are more efficacious and / or exhibit advantageous properties in vivo.

[0122] Brief Description of the Figures

[0123] Figure 1 shows the inhibition profile of Pl' N-Boc amino acids and Pl' amino acids (2- 24) on the LU-005i (1) scaffold in an ICso (pM) heatmap;

[0124] Figure 2 shows the inhibition profile of Pl' N-Boc esters (25-27) on the LU-005i (1) scaffold in an IC50 (pM) heatmap; Figure 3 shows the inhibition profile of a P3-P4 scaffold screen (28-57) based on the LU-005i (1) scaffold in an ICso (pM) heatmap;

[0125] Figure 4 shows the inhibition profile of a secondary P3-P4 screen (29 30, 34, 35, 58- 73) based on the LU-005i (1) scaffold in an IC50 (pM) heatmap;

[0126] Figure 5 shows the inhibition profile in Raji lysates of a set of compounds with variations on the P3 position and the Pl' position (2, 3, 14, 65, 68, 74-76) in an ICso (pM) heatmap;

[0127] Figure 6 shows the inhibition profile in AMO wildtype lysates of a set of compounds with variations on the P3 postion and the Pl' position (2, 3, 14, 65, 68, 74-76) in an ICso (pM) heatmap.

[0128] For the avoidance of doubt, the numbering used in figure legends refers to the numbering of compounds of the examples as provided herein.

[0129] Examples

[0130] The present invention will be further described by reference to the following examples, which are not intended to limit the scope of the invention.

[0131] In the event that there is a discrepancy between nomenclature and any compounds depicted graphically, then it is the latter that presides (unless contradicted by any experimental details that may be given or unless it is clear from the context).

[0132] Starting materials and intermediates used in the synthesis of compounds described herein are commercially available or can be prepared by the methods described herein or by methods known in the art.

[0133] Commercially available reagents and solvent were used as received. H2O and oxygen sensitive reactions were performed under N2 atmosphere. Solvents used in synthesis were, if necessary, dried, and stored over 4& molecular sieves, except for Pyridine, DIPEA and TEA which were stored over KOH pellets. TLC analysis was performed using aluminum sheets, pre-coated with silica gel (Merck, TLC silica gel 60 F254). Compounds were visualized by UV absorption (A = 254 nm) or spraying with Ninhydrin (50 g / L in n-butanol) or Cerium molybdate (25 g / L (NH4)6Mo?O24, 10 g / L (NH4Ce(SO4)4®H2O in 10% H2SO4 water solution), and where appropriate, followed by charring at 150 °C. Column chromatography was performed on screening devices b.v. Silica gel (particle size 40-63 pm, pore diameter 60 A). Celite hyflo supercell (Merck) was used to impregnate reaction mixtures prior to silica gel chromatography when appropriate. 1H, 13C APT, 1H Cosy and HSQC spectra were recorded with a brucker AV-400 (400 / 100 MHz), AV-500 (500 / 125 MHz) spectrometer. Chemical shifts are reported as d values (ppm) and were referenced to TMS (8 = 0.00 ppm) or the residual solvent peak. J couplings are reported in Hz. Liquid chromatography mass spectrometry analysis was performed on a Finnigan surveyor HPLC system with a nucleodur C18 Gravity 3 pm 50 x 4,60 mm column (detection at 200 - 500 nm) coupled to a Finnigan LCQ advantage max mass spectrometer with ESI or a Thermo LCQ Fleet ion mass spectrometer with ESI. The general method used was 10 to 90% with a total run time of 13.5 minutes.

[0134] High resolution mass spectra were reported by direct injection (1,0 pM solution in HzO / MeCN 1 : 1 and 0.1% formic acid) on a mass spectrometer (Q Exactive HF hybrid quadrupole-orbitrap) equipped with an electrospray ion source in positive mode (source voltage 3.5 kV, Sheath gas flow 10, capillary temperature 275 °C) with resolution R = 240.000 at m / z 400 (mass range m / z = 160 - 2000) and an external lock mass. The high-resolution mass spectrometer was calibrated prior to measurements with a calibration mixture (Thermo Finnigan).

[0135] For syntheses referencing general procedures, reaction conditions (such as length of reaction or temperature) may vary. In general, reactions were followed by thin layer chromatography or LC-MS, and subjected to work-up when appropriate. Purifications may vary between experiments: in general, solvents and the solvent ratios used for eluents / gradients were chosen to provide an appropriate Rf and / or retention time.

[0136] General procedures

[0137] General chemical syntheses of LU-005i-OH and structural variants:

[0138] Epoxyketone 83 was prepared as follows (Scheme 1). Condensation of the Weinreb salt with / V-Boc cyclohexylalanine 77 using HCTU provided Weinreb amide 78. Deprotonation of dimethylmethylphosphonate using n-BuLi resulted in the formation of a phosphorus ylide that was then added to Weinreb amide 78 to form phosphonate 79. In a two-step, one-pot reaction phosphonate 83 was deprotonated forming the phosphorus ylide intermediate, which in a Horner-Wadsworth-Emmons reaction with formaldehyde gave enone intermediate 80, that immediately reacts in a Baylis-Hillman type reaction with formaldehyde to form allylic alcohol 81. Allylic alcohol 81 was then epoxidized using hydrogen peroxide in a nucleophilic epoxidation to provide in the desired stereochemistry epoxyketone 82 after separation of the diastereomers. The / V- Boc protective group in 82 was then removed using TEA in DCM, resulting in epoxyketone building block 83.

[0139] Scheme 1. Synthesis of epoxyketone 83. Reagents and conditions; (a) HCI*NMeOMe, HCTU, DiPEA, DCM, rt, 91%; (b) dimethylmethylphosphonate, n-BuLi, THE, -78 °C; (c) formaldehyde, K2CO3, HzO / MeOH, 0 °C, 51%; (d) H2O2, DiPEA, benzonitrile, 0 °C, 29%; (e) TEA, DCM, rt, quant.

[0140] Next, both the phenolic alcohol and carboxylate of / V-Boc tyrosine were methylated using iodomethane and potassium carbonate, forming 4-methoxyphenylalanine ester 85 (Scheme 2). The / V-Boc protective group of 85 was then removed, and the resulting amine was condensed with / V-Boc alanine using HCTU to form dipeptide 86. De- / V-Bocylation of 86 (treatment with TEA) followed by condensation of the NH2- dipeptide intermediary with 2-morpholinoacetic acid gave methyl ester 87. Methyl ester 87 was converted to acyl hydrazide 88 which was then converted into acyl azide 89 using tert-butyl nitrite under anhydrous acidic conditions. Subsequently, acyl azide 89 was reacted with / W-fe-epoxyketone 83 to form LU-005i-OH 2. The OH group in 2 was then functionalised through Streglich esterification with a wide scope of carboxylic acids to form the library of esterified LU-005i-OH derivatives 3-13 and 25-26. Finally, the respective / V-Boc and O-TBS protective groups in compounds 2-12 and 26 were then removed through treatment with TFA to afford a set of Nl- -ammo acid ester derivatives 14-24 and O / 7-lactic acid ester derivative 27.

[0141]

[0142] Scheme 2. Synthesis of LU-005i-OH 2 and esterified LU-005i-OH derivatives 3-27. Reagents and conditions: (a) Mel, K2CO3, DMF rt, quant.; (b) i: TFA, DCM, rt, ii: NH2- Ala-OMe, HCTU, DiPEA, DCM, rt, 91%; (c) i : TFA, DCM, ii: morpholinoacetic acid, HCTU, DiPEA, DCM, rt, 80%; (d) hydrazine hydrate, MeOH, rt; (e) i : tBuONO, HCI, DMF, -30 °C, ii : 83, DiPEA, DMF, -30 °C -> rt, 69%; (f) RCO2H, DIC, DMAP, DCM, rt, 34-99%; (g) TFA, DCM, rt.

[0143] Procedure A: Boc Deprotection

[0144] The Boc-protected compound is dissolved in anhydrous DCM (0.3 M) and TFA is added to this solution to achieve a 1 :4 (v:v) ratio of TFA: DCM. The reaction mixture was left to stir for 1 to 2 hours and monitored by TLC. Upon full conversion, the reaction mixture was concentrated in vacuo and co-evaporated 3x with toluene.

[0145] Procedure B: Esterification

[0146] LU-005i-OH was dissolved in anhydrous DCM (0.2 M) and purged with N2. To this solution DIC (2.0 eq.), amino acid (1.1 eq.) and DMAP (1.1 eq.) were added. The resulting reaction mixture was left stirring for 16 hours at room temperature. The reaction mixture was concentrated in vacuo and silica gel column chromatography with DCM : MeOH yielded the title compounds.

[0147] Boc-Tyr(OMe)-OMe (90)

[0148] Boc-Tyr(OMe)-OH (5 g; 16.9 mmol, 1.0 eq.) was dissolved in anhydrous DMF (0.1 M), purged with N2 and cooled to 0 °C. Mel (1.27 ml; 20.3 mmol; 1.2 eq) and K2CO3 (3.27 g; 23.66 mmol; 1.5 eq) were added and the reaction mixture was left to stir for 16 hours at room temperature. The reaction mixture was diluted with EtOAc, washed with NaS2Os (sat., aq.), H2O and brine (NaCI sat., aq.), dried over MgSC , filtered, and concentrated in vacuo. The title compound was obtained without the need of further purification (6.06 g; 19.6 mmol; quant). LC-MS (linear gradient 10 to 90% MeCN / HzO, 0.1% TFA, 12.5 min) Rt (min) : 6.53 min (ESI-MS (m / z): 310.16 (M + H+)).

[0149] H2N-Tyr(OMe)-OMe (85)

[0150] The deprotection of Boc-Tyr(OMe)-OMe was performed according to procedure A on a 19.6 mmol scale yielding the title compound as a white solid (5.49 g; 19.6 mmol; quant). LC-MS o 90% MeCN / HzO, 0.1% TFA, 12.5 min) Rt (min) : 6.25 min (ESIM + H+)). Boc-Ala-Tyr(OMe)-OMe (86) H2N-Tyr(OMe)-OMe (4.10 g; 19.6 mmol; 1.0 eq.) was co- evaporated with toluene two times, then dissolved in anhydrous DMF (0,2 M) and purged with N2. To this solution HCTU (12,16 g; 29.4 mmol; 1.5 eq.) and Boc-Ala-OH (7.42 g; 39.2 mmol; 2.0 eq.) were added. When fully dissolved DiPEA (13.7 ml; 78.4 mmol; 4.0 eq.) was added dropwise to the reaction mixture and left stirring for 16 h. The reaction mixture was washed with HCI (1.0 M, aq.), NaHCCh (sat., aq.) and brine (NaCI sat., aq.), dried over MgSC and concentrated in vacuo. Silica gel column chromatography (0: 100 -> 2: 100 MeOH: DCM) yielded the title compound as a colourless oil (6.79 g; 17.8 mmol; 91%). R 0.2 in 2: 100 MeOH :DCM.1H NMR (400 MHz, CDCh) 5 7.05 - 7.00 (m, 2H), 6.90 (d, J = 8.0 Hz, 1H), 6.82 - 6.78 (m, 2H), 5.39 (d, J = 7.6 Hz, 1H), 4.79 (q, J = 6.4, 1H), 4.26 - 4.18 (m, 1H), 3.75 (s, 3H), 3,68 (s, 3H), 3.04 (qd, J = 14.0, 6.0, 2H), 1.43 (s, 9H), 1.30 (d, J = 7.1 Hz, 3H).13C NMR (101 MHz, CDCh) 5 172.5, 171.8, 158.5, 155.3, 130.2, 127.7, 113.8, 79.7, 55.0, 53.3, 52.1, 49.9, 36.9, 28.2, 18.3. LC-MS (linear gradient 10 to 90% MeCN / H2O, 0.1% TFA, 12.5 min) Rt (min) : 6.71 min (ESI-MS (m / z) : 380.80 (M + H+)).

[0151] H2N-Ala-Tyr(OMe)-OMe (91) yielding the title compound as a yellow oil (2.24 g; 8.0 mmol; quant). LC-MS (linear gradient 10 to 90% MeCN / HzO, 0.1% TFA, 12.5 min) Rt (min) : 4.03 min (ESI-MS (m / z) : 281.00 (M + H+)). anhydrous DMF (0,2 M) and purged with N2. To this solution PyBOP (4.03 g; 9.6 mmol; 1.2 eq.) and Morph-COOH (1.28 g; 8.8 mmol; 1.1 eq.) were added. When fully dissolved DiPEA (4.89 ml; 28.0 mmol; 3.5 eq.) was added dropwise to the reaction mixture and left stirring for 16 h. The reaction mixture was washed with HCI (1,0 M, aq.), NaHCCh (sat., aq.) and brine (NaCI sat., aq.), dried over MgSO4 and concentrated in vacuo. Silica gel column chromatography (0 : 100 -> 2 : 100 MeOH : DCM) yielded the title compound as a yellowish oil (2.61 g, 6.4 mmol; 80%). Rf: 0.3 in 2 : 100 MeOH : DCM.1H NMR (400 MHz, CDCh) 5 7.55 (t, J = 7.9 Hz, 1H), 7.11 - 6.93 (m, 2H), 6.88 - 6.75 (m, 2H), 6.68 (d, J = 7.8 Hz, 1H), 4.77 (ddd, J = 7.9, 6.7,

[0152] 5.5, 1H), 4.51 (p, J = 7.1 Hz, 1H), 3.77 (s, 3H), 3.73 (s, 3H), 3.70 (t, J = 4.7 Hz, 4H), 3.14 - 2.89 (m, 4H), 2.49 (t, J = 4.6 Hz, 4H), 1.36 (d, J = 7.0 Hz, 3H).13C NMR (101 MHz, CDCh) 5 171.9, 171.9, 169.9, 158.7, 130.3, 127.7, 114.0, 66.9, 61.7, 55.3, 53.8,

[0153] 53.5, 52.5, 36.9, 18.2. LC-MS (linear gradient 10 to 90% MeCN / HzO, 0.1% TFA, 12.5 min) Rt (min) : 4.29 min (ESI-MS (m / z) : 408.07 (M + H+)).

[0154] Mor h-Ala-T r(OMe)-NHNH (88) Hydrazine hydrate (65% mass percentage; 1.88 ml; 60.0 mmol; 30.0 eq.) was added. The resulting reaction mixture was left stirring 16 h at rt. The resulting reaction mixture was concentrated in vacuo and co-evaporated with toluene three times. This yielded a white solid and was further used as a crude for the following reaction. LC-MS (linear gradient 10 to 90% MeCN / H2O, 0.1% TFA, 12.5 min) Rt (min) : 3.03 min (ESI-MS (m / z) : 408.20 (M + H+)).

[0155] Boc-Cha-N(OCH3)CH3(78) Boc-Cha-OH (10.0 g; 36.9 mmol; 1.0 eq.) was dissolved in anhydrous DMF (0.1 M) and purged with N2. To this solution HCTU (22.87 g, 55.3 mmol, 1.5 eq) and N,O, -dimethylhydroxylamine (7.19 g; 73.7 mmol; 2.0 eq.) were added. When reagents were fully dissolved DiPEA (25.7 ml; 147 mmol; 4.0 eq.) was added dropwise and the resulting yellow reaction mixture was left stirring for 16 hours. The reaction mixture was then acidified with HCI (1.0 M, aq.), washed with HCI (1.0 M, aq.), NaHCCh (sat., aq.) and brine (sat. NaCI, aq.), dried over MgSC and concentrated in vacuo. Silica gel column chromatography (1 : 20 -> 1 :4 EtOAc: PE) yielded the title compound as a transparent oil (10.43 g, 33.2 mmol; 90%). Rf: 0.3 in 1 :4 EtOAc: PE.1H NMR (400 MHz, CDCh) 5 5.02 (d, J = 9.2 Hz, 1H), 4.87 - 4.55 (m, 1H), 3.78 (s, 3H), 3.20 (s, 3H), 1.91 (d, J = 12.6 Hz, 1H), 1.82 - 1.55 (m, 5H), 1.54 - 1.46 (m, 1H), 1.45 - 1.32 (m, 10H), 1.31 - 1.06 (m, 3H), 1.04 - 0.82 (m, 2H).13C NMR (101 MHz, CDCh) 5 155.82, 155.79, 79.62, 61.74, 48.47, 40.67, 34.19, 34.12, 32.36, 32.28, 28.50, 26.62, 26.42, 26.20. LC-MS (linear gradient 10 to 90% MeCN / H2O, 0.1% TEA, 12.5 min) Rt (min): 8.40 min (ESI-MS (m / z): 314.80 (M + H+)).

[0156] Boc-Cha-CH2-P(=O)OMe(OMe) (79) Dimethyl methylphosphonate (7.48 ml; 70 mmol; 4.0 eq) was dissolved in anhydrous THE (0.1 M), purged with N2 and cooled to -78 °C. n-BuLi (2.5 M in Hexane; 28.0 ml; 70.0 mmol; 4.0 eq) was added dropwise to the solution. The resulting reaction mixture was stirred for 2 hours under N2 at -78 °C. Boc-Cha-N(OCH3)CH3 (5.5 g; 17.5 mmol; 1.0 eq.) was co-evaporated with toluene two times, dissolved in anhydrous THE and purged with N2. The Boc-Cha- N(OCH3)CH3 containing THE solution was added dropwise to the phosphor ylide- containing solution. The resulting reaction mixture was left stirring for 3 hours at -78 °C under N2 atmosphere. Next the reaction was quenched using NH4CI (100 ml; sat., aq.) followed by heating the reaction mixture to room temperature. The reaction mixture was then diluted with EtOAc and the resulting organic- and aqueous layers were partitioned. The resulting aqueous layer was extracted with EtOAc three times and the combined EtOAc was washed with H2O and brine (NaCI sat., aq.), dried over MgSO4 and concentrated in vacuo. The resulting crude oil was used in the next reaction without further purification.1H NMR (400 MHz, CDCh) 6 5.24 (d, J = 26.3 Hz, 1H), 4.36 (d, J = 11.5 Hz, 1H), 3.80 (d, J = 3.9 Hz, 3H), 3.78 (d, J = 3.8 Hz, 4H), 3.75 (s, 6H), 3.73 (d, J = 2.4 Hz, 6H), 3.34 (dd, J = 22.5, 14.2 Hz, 1H), 3.10 (dd, J = 22.0, 14.2 Hz, 1H), 1.90 - 1.58 (m, 8H), 1.45 (s, 15H), 1.41 - 1.31 (m, 3H), 1.29 - 1.10 (m, 5H), 1.03 - 0.81 (m, 4H). LC-MS (linear gradient 10 to 90% MeCN / H2O, 0.1% TEA, 12.5 min) Rt (min): 7.48 min (ESI-MS (m / z): 377.67 (M + H+)). Boc-Cha-C(CH2OH) = CH2(81) Boc-Cha-CH2-P(=O)OMe-OMe (5.9 g; 17.5 mmol; 1.0 eq.) was dissolved in a 1: 1 ratio of THE and H2O (0.1 M). K2CC>3 (7.26 g; 52.5 mmol; 3.0 eq) and formaldehyde (37% mass percentage in H2O;

[0157] 3.91 ml; 52.5 mmol; 3.0 eq.) were added to the solution. The reaction mixture was left stirring for 16 hours at room temperature. The reaction mixture was diluted with EtOAc and acidified using HCI (1.0 M, aq.). The organic and aqueous layers were partitioned, and the aqueous layer was extracted three times with EtOAc. The resulting EtOAc was washed with H2O and brine (NaCI sat., aq.), dried over MgSO4, filtered, and concentrated in vacuo. Silica gel column column chromatography (1 :20 -> 1:4 EtOAc:PE, v:v). This procedure yielded the title compound (2.42 g; 8.93 mmol; 51 %).1H NMR (400 MHz, CDCh) 5 6.21 (d, J = 33.7 Hz, 2H), 5.57 (d, J = 8.8 Hz, 1H), 5.12 - 5.03 (m, 1H), 4.39 - 4.23 (m, 2H), 1.76 - 1.50 (m, 7H), 1.42 (s, 13H), 1.37 - 1.06 (m, 6H), 1.02 - 0.81 (m, 3H). LC-MS (linear gradient 10 to 90% MeCN / H2O, 0.1% TEA, 12.5 min) Rt (min): 7.81 min (ESI-MS (m / z): 311.60 (M + H+)).

[0158] Boc-Cha-EK-CHsOH (82)

[0159] Boc-Cha-C(CH3OH) = CH2 (3.4 g; 11 mmol; 1.0 eq.) was dissolved in MeOH (0.2 M), cooled to 0 °C and hydrogen peroxide (3.14 ml; 55 mmol; 5.0 eq.), benzonitrile (5.66 ml; 55 mmol; 5.0 eq.) and DiPEA (9.58 ml; 55 mmol; 5.0 eq.) were added. The resulting reaction mixture was left stirring for 16 hours at 0 °C. The reaction mixture was diluted with EtOAc and acidified with HCI (1.0 M, aq.). The organic and aqueous layers were partitioned, and the aqueous layer was extracted with EtOAc three times. The resulting EtOAc layer was dried over Mg2SO4, filtered, and concentrated in vacuo. The crude contained the product as a racemic mixture. The intended S isomer was isolated by a slow and thorough separation which was achieved by increasing the concentration of the eluent by one percentage point starting from 10% EtOAc / PE. Finally, purification by flash column chromatography (5% -> 15% (v / v) EtOAc:PE) yielded the title compound (1.1 g; 3. 22 mmol; 29%).XH NMR (400 MHz, CDCI3) 5 4.91 (d, J = 8.6 Hz, 1H), 4.39 - 4.28 (m, 1H), 4.19 (dd, J = 12.7, 4.6 Hz, 1H), 3.76 (dd, J = 12.8, 5.5 Hz, 1H), 3.33 (d, J = 5.0 Hz, 1H), 3.09 (d, J = 5.0 Hz, 1H), 2.37 (t, J = 6.3 Hz, 1H), 1.86 (d, J = 10.9 Hz, 1H), 1.77 - 1.53 (m, 6H), 1.42 (s, 12H), 1.33 - 1.07 (m, 6H), 1.05 - 0.86 (m, 3H).13C NMR (101 MHz, CDCh) 5 208.7, 155.7, 79.9, 62.0, 61.1, 60.4, 53.2, 51.3, 49.2, 37.9, 34.3, 34.0, 31.8, 28.3, 26.4, 26.2, 25.9, 21.0, 14.2. LC-MS (linear gradient 10 to 90% MeCN / H2O, 0.1% TEA, 12.5 min) Rt (min): 7.65 min (ESI-MS (m / z): 327.53 (M + H+)).

[0160] H2N-Cha-EK-CH3OH (83) The deprotection of Boc-Cha-EK-CH3OH was performed according to procedure A on a mmol scale yielding the title compound as a yellow oil (0.38 g; 1.08 mmol; quant). LC-MS (linear gradient 10 to 50% MeCN / H2O, 0.1% TFA, 12.5 min) Rt (min): 4.43 min (ESI- MS (m / z): 228.07 (M + H+)). with Nz and cooled to -40 °C. To this solution tBuONO (0.438 ml; 3.67 mmol; 2.2 eq.) and HCI (4.0 M in dioxane; 2.33 ml; 9.33 mmol; 5.6 eq.) were added. The resulting reaction mixture was left stirring for four hours at -40 °C. After four hours the HCI was quenched with DiPEA (1.16 ml; 6.67 mmol; 4.0 eq.) and a solution of NH2-Cha-EK-CH3OH (0.379 g; 1.70 mmol; 1.0 eq.) in anhydrous DMF (0.2 M) was added dropwise. The resulting reaction mixture was left stirring 16 hours, while over this period of time heating back to room temperature. The reaction mixture was diluted with H2O and EtOAc, washed with NaHCCh (sat., aq.), H2O and brine (sat. NaCI, aq.), dried over MgSC and concentrated in vacuo. Silica gel column chromatography (0 : 100 -> 10 : 100 MeOH : DCM) yielded the title compound as a transparent oil (0.71 g, 1.17 mmol; 69%). Rf: 0.35 5: 100 MeOH : DCM. H NMR (400 MHz, CDCh) 5 7.47 (d, J = 7.5 Hz, 1H), 7.16 - 7.06 (m, 2H), 6.86 (d, J = 7.7 Hz, 1H), 6.83 - 6.76 (m, 2H), 6.50 (d, J = 7.7 Hz, 1H), 4.63 - 4.51 (m, 2H), 4.44 (p, 7 = 7.1 Hz, 1H), 4.17 (d, J = 12.6 Hz, 1H), 3.76 (s, 3H), 3.73 (d, J = 5.1 Hz, 1H), 3.70 (t, J = 4.6 Hz, 4H), 3.29 (d, J = 5.0 Hz, 1H), 3.07 (d, J = 5.0 Hz, 1H), 3.00 (d, J = 6.9 Hz, 2H), 2.95 (s, 1H), 2.89 (s, 1H), 2.46 (q, J = 4.2 Hz, 5H), 1.78 (d, J = 13.0 Hz, 1H), 1.72 - 1.49 (m, 5H), 1.35 (d, J = 7.0 Hz, 3H), 1.28 - 1.09 (m, 6H), 1.01 - 0.82 (m, 2H).13C NMR (101 MHz, CDCh) 5 207.6, 206.1, 172.0, 170.9, 170.3, 158.6, 130.4, 128.2, 114.0, 66.9, 62.6, 62.0, 61.6, 61.4, 55.2, 54.3, 53.7, 52.1, 51.7, 50.4, 49.3, 48.4, 37.7, 36.7, 34.3, 33.8, 31.8, 26.3, 26.2, 25.9, 17.8. LC-MS (linear gradient 10 to 90% MeCN / HzO, 0.1% TFA, 12.5 min) Rt (min) : 5.12 min (ESI-MS (m / z) : 603.27 (M + H+)). HRMS (ESI) m / z: [M + H+] calc for C31H46N4O8 603.33884, found 603.33823 mmol; 1.0 eq.) with Boc-Ala-OH (12 mg;

[0161] 0.066 mmol; 2.0 eq.) according to procedure B. Silica gel column chromatography (3% (v / v) MeOH / DCM) yielded the title compound (18 mg; 0.023 mmol; 70%) as a white powder after lyophilization.XH NMR (500 MHz, CDCh) 6 7.46 (d, J = 7.5 Hz, 1H), 7.12 (d, J = 8.6 Hz, 2H), 6.81 (d, J = 6.7 Hz, 3H), 6.42 (d, J = 7.5 Hz, 1H), 5.05 (d, J = 7.7 Hz, 1H), 4.89 (d, J = 12.2 Hz, 1H), 4.62 - 4.49 (m, 2H), 4.41 (p, 7 = 7.1 Hz, 1H), 4.30 (d, J = 7.5 Hz, 1H), 4.13 (d, J = 12.2 Hz, 2H), 3.83 (q, J = 6.4 Hz, 2H), 3.77 (s, 3H), 3.70 (t, J = 4.7 Hz, 4H), 3.37 (d, J = 4.9 Hz, 1H), 3.06 (d, J = 4.9 Hz, 1H), 3.02 - 2.98 (m, 2H), 2.96 (s, 1H), 2.88 (d, J = 16.4 Hz, 1H), 2.48 (tq, J = 11.8, 6.9, 5.6 Hz, 4H), 1.80 - 1.52 (m, 6H), 1.45 (s, 9H), 1.41 - 1.33 (m, 6H), 1.29 - 1.17 (m, 5H), 0.98 - 0.83 (m, 2H).13C NMR (126 MHz, CDCb) 5 205.4, 172.7, 172.0, 171.0, 170.3, 158.7, 157.0, 130.5, 128.3, 114.1, 66.9, 63.3, 61.7, 59.8, 55.3, 54.3, 53.8, 50.1, 49.4, 49.2, 48.5, 42.3, 37.6, 36.7, 34.3, 34.0, 31.9, 29.5, 28.4, 26.4, 26.2, 27.0, 23.6, 18.8, 17.7. LC-MS (linear gradient 10 to 90% MeCN / HzO, 0.1% TFA, 12.5 min) Rt (min) : 6.61 min (ESI-MS (m / z) : 774.20 (M + H+)). mmol) according to procedure B. Silica gel column chromatography (3% (v / v)

[0162] MeOH / DCM) yielded the title compound (8.0 mg; 0.010 mmol; 60%) as a white powder after lyophilization.XH NMR (500 MHz, CDCb) 5 7.13 (d, J = 8.2 Hz, 1H), 6.81 (d, J = 8.1 Hz, 1H), 4.55 (dd, J = 29.2, 7.9 Hz, 1H), 4.39 (dt, J = 14.0, 7.1 Hz, 1H), 4.24 (s, 8H), 4.18 - 4.04 (m, 1H), 3.84 (q, J = 6.6 Hz, 8H), 3.77 (d, J = 4.6 Hz, 4H), 3.71 (s,

[0163] 2H), 2.61 (s, 3H), 2.49 (s, 1H), 2.05 (s, 1H), 1.82 - 1.52 (m, 5H), 1.46 (d, J = 11.1 Hz, 11H), 1.36 (d, 7 = 7.1 Hz, 2H), 1.26 (s, 20H), 1.14 (d, J = 6.5 Hz, 52H), 0.96 (d, J = 6.8 Hz, 1H), 0.92 - 0.82 (m, 7H). LC-MS (linear gradient 10 to 90% MeCN / H2O, 0.1% TFA, 12.5 min) Rt (min) : 10.42 min (ESI-MS (m / z) : 802.22 (M + H+)). according to procedure B. Silica gel column chromatography (3% (v / v) MeOH / DCM) yielded the title compound (17 mg; 0.020 mmol; 60%) as a white powder after lyophilization.XH NMR (400 MHz, CDCb) 5 7.44 (d, J = 7 A Hz, 1H), 7.13 (d, J = 8.6 Hz, 2H), 6.81 (d, J = 8.6 Hz, 2H), 6.73 (d, J = 7.5 Hz, 1H), 6.31 (d, J = 7.4 Hz, 1H), 5.04 (d, J = 8.9 Hz, 1H), 4.93 (d, J = 12.1 Hz, 1H), 4.61 - 4.48 (m, 2H), 4.41 (p, J = 7.1 Hz, 1H), 4.26 (dd, J = 9.0, 4.6 Hz, 1H), 4.04 (d, J = 12.2 Hz, 1H), 3.78 (s, 3H), 3.70 (t, J = 4.7 Hz, 4H), 3.38 (d, J = 4.9 Hz, 1H), 3.06 (d, J = 4.9 Hz, 1H), 3.03 - 2.97 (m, 2H), 2.95 (s, 1H), 2.87 (d, J = 16.5 Hz, 1H), 2.46 (q, J = 4.8 Hz, 4H), 1.82 (s, 4H), 1.78 - 1.53 (m, 7H), 1.45 (s, 10H), 1.37 (d, J = 7.0 Hz, 3H), 1.21 (d, J = 35.3 Hz, 7H), 0.92 (dd, J = 9.3, 7.1 Hz, 9H).13C NMR (101 MHz, CDCh) 5 205.2, 171.9, 170.9, 170.3, 158.6, 130.4, 128.2, 114.0, 79.9, 66.9, 63.3, 61.6, 59.7, 57.8, 55.2,

[0164] 54.2, 53.7, 50.0, 49.5, 48.4, 42.3, 38.2, 37.5, 37.0, 34.3, 34.0, 31.8, 29.6, 28.3,

[0165] 26.3, 26.2, 25.9, 25.1, 23.5, 17.5, 15.4, 11.8. LC-MS (linear gradient 10 to 90% MeCN / HzO, 0.1% TFA, 12.5 min) Rt (min) : 7.28 min (ESI-MS (m / z) : 816.33 (M + H+)). mmol) according to procedure B. Silica gel column chromatography (3% (v / v)

[0166] MeOH / DCM) yielded the title compound (17 mg; 0.020 mmol; 61%) as a white powder after lyophilization.XH NMR (400 MHz, CDCI3) 5 7.47 (d, J = 7.5 Hz, 1H), 7.29 (d, J = 11.6 Hz, 5H), 7.13 (d, J = 8.7 Hz, 4H), 6.81 (d, J = 8.5 Hz, 3H), 6.42 (d, J = 7.5 Hz, 1H), 4.96 (d, J = 8.3 Hz, 1H), 4.90 (d, J = 12.2 Hz, 1H), 4.62 - 4.48 (m, 3H), 4.42 (p, J = 7.1 Hz, 1H), 4.16 (s, 2H), 4.05 (d, J = 12.1 Hz, 1H), 3.84 (dq, J = 13.4, 6.7 Hz, 2H), 3.77 (s, 3H), 3.70 (t, J = 4.7 Hz, 4H), 3.35 (d, J = 4.9 Hz, 1H), 3.12 (dd, J = 13.9, 5.7 Hz, 1H), 3.05 (d, J = 5.8 Hz, 1H), 3.03 - 2.97 (m, 3H), 2.96 (s, 1H), 2.87 (d, J = 16.4 Hz, 1H), 2.47 (q, J = 4.6 Hz, 4H), 1.80 - 1.51 (m, 7H), 1.41 (d, J = 5.6

[0167] Hz, 8H), 1.37 (d, J = 7.1 Hz, 4H), 1.25 (s, 6H), 0.96 - 0.81 (m, 3H).13C NMR (101

[0168] MHz, CDCI3) 5 205.3, 171.9, 171.1, 171.0, 158.6, 156.9, 154.9, 135.7, 130.4, 129.4, 128.7, 128.2, 127.1, 114.0, 80.0, 66.9, 63.4, 61.6, 59.7, 55.2, 54.3, 54.2, 53.7, 50.0,

[0169] 49.3, 48.5, 42.2, 38.3, 37.5, 36.6, 34.3, 33.9, 31.8, 29.7, 28.3, 26.3, 26.2, 25.9, 23.5, 17.6. LC-MS (linear gradient 10 to 90% MeCN / HzO, 0.1% TFA, 12.5 min) Rt (min) : 7.34 min (ESI-MS (m / z) : 850.33 (M + H+)). (23 mg; 0.066 mmol) according to procedure B. Silica gel column chromatography (3% (v / v) MeOH / DCM) yielded the title compound (33 mg; 0.035 mmol; quant.) as a white powder after lyophilization.XH NMR (400 MHz, CDCh) 5 7.55 (dd, J = 16.5, 8.1 Hz, 4H), 7.44 (d, J = 8.7 Hz, 3H), 7.39 - 7.31 (m, 1H), 7.21 (d, J = 7.9 Hz, 2H), 7.12 (d, J = 8.6 Hz, 2H), 6.85 - 6.74 (m, 3H), 6.42 (d, J = 7 A Hz, 1H), 5.01 (d, J = 8.3 Hz, 1H), 4.93 (d, J = 12.1 Hz, 1H), 4.66 - 4.58 (m, 1H), 4.58 - 4.49 (m, 2H), 4.41 (p, J = 7.1 Hz, 1H), 4.25 (d, J = 7.9 Hz, 4H), 4.06 (d, J = 12.2 Hz, 1H), 3.91 - 3.79 (m, 5H), 3.77 (s, 3H), 3.69 (t, J = 4.6 Hz, 4H), 3.37 (d, J = 4.9 Hz, 1H), 3.17 (dd, J = 13.8, 5.7 Hz, 1H), 3.09 (dd, J = 13.9, 5.8 Hz, 1H), 3.03 (d, J = 4.9 Hz, 1H), 3.01 - 2.96 (m, 2H), 2.94 (s, 1H), 2.86 (d, J = 16.4 Hz, 1H), 2.45 (q, J = 4.4 Hz, 4H), 1.80 - 1.52 (m, 6H), 1.43 (s, 7H), 1.36 (d, J = 7.0 Hz, 4H), 1.32 - 1.19 (m, 4H), 1.02 - 0.81 (m, 3H).13C NMR (101 MHz, CDCb) 5 205.2, 171.9, 171.1, 171.0, 170.3, 158.6, 157.0, 140.7, 134.7, 130.4, 129.8, 128.8, 128.2, 127.4, 127.3, 127.0, 114.0, 66.9, 63.6, 61.6, 59.7, 55.2, 54.2, 53.8, 48.4, 42.1, 37.9, 37.5, 36.6, 34.3, 33.9, 31.7, 28.3, 26.2, 25.9, 22.7, 18.2. LC-MS (linear gradient 10 to 90% MeCN / HzO, 0.1% TEA, 12.5 min) Rt (min) : 8.00 min (ESI-MS (m / z) : 926.40 (M + H+)). mmol) with Boc-Asn-OH (7.7 mg; 0.0332 mmol) according to procedure B. Silica gel column chromatography (3% (v / v) MeOH / DCM) yielded the title compound (4.7 mg; 0.006 mmol; 34%) as a white powder after lyophilization.XH NMR (500 MHz, CDCb) 5 7.43 (s, 1H), 7.18 (d, J = 7.0 Hz, 1H), 7.11 (d, J = 8.5 Hz, 2H), 6.81 (d, J = 7.8 Hz, 3H), 6.72 (d, J = 11.8 Hz, 1H), 6.49 (s, 1H), 5.84 (s, 1H), 5.75 (d, J = 8.5 Hz, 2H), 4.84 - 4.69 (m, 1H), 4.54 (t, J = 7.1 Hz, 4H), 4.38 (p, J = 7.0 Hz, 2H), 4.27 (s, 1H), 3.78 (s, 4H), 3.71 (s, 5H), 3.34 (d, J = 5.0 Hz, 1H), 3.09 (d, J = 4.8 Hz, 1H), 3.04 - 2.93 (m, 4H), 2.86 (d, J = 16.0 Hz, 2H), 2.71 (d, J = 11.2 Hz, 1H), 2.46 (s, 5H), 2.36 (s, 2H), 1.87 - 1.51 (m, 17H), 1.45 (d, 7 = 1.1 Hz, 13H), 1.36 (d, J = 7.0 Hz, 6H), 1.26 (s, 45H), 0.99 - 0.79 (m, 14H). LC- MS (linear gradient 10 to 90% MeCN / HzO, 0.1% TEA, 12.5 min) Rt (min) : 6.31 min

[0170] (ESI-MS (m / z) : 817.25 (M + H+)).

[0171] 0.066 mmol) according to procedure B. Silica gel column chromatography (3% (v / v) MeOH / DCM) yielded the title compound (17 mg; 0.019 mmol; 57%) as a white powder after lyophilization.XH NMR (300 MHz, CDCb) 5 7.43 (d, J = 7.4 Hz, 1H), 7.35 (t, J = 2.2 Hz, 5H), 7.11 (d, J = 8.6 Hz, 2H), 6.85 - 6.77 (m, 2H), 6.74 (d, J = 7.6 Hz, 1H), 6.34 (d, J = 7.5 Hz, 1H), 5.48 (d, J = 8.6 Hz, 1H), 4.89 (d, J = 12.2 Hz, 1H), 4.62 - 4.46 (m, 3H), 4.41 (p, 7 = 7.1 Hz, 1H), 4.07 (d, J = 12.3 Hz, 1H), 3.77 (s, 3H), 3.70 (t, J = 4.6 Hz, 4H), 3.48 (s, 2H), 3.32 (d, J = 5.0 Hz, 1H), 3.06 - 2.92 (m, 5H), 2.89 (d, J = 6.3 Hz, 2H), 2.84 (d, J = 5.7 Hz, 1H), 2.45 (q, J = 4.0 Hz, 4H), 1.89 - 1.49 (m, UH), 1.44 (s, 10H), 1.36 (d, J = 7.0 Hz, 4H), 1.30 - 1.03 (m, 7H), 1.00 - 0.77 (m, 3H).13C NMR (75 MHz, CDCh) 5 205.2, 171.9, 170.9, 170.3, 158.6, 135.3, 130.4, 128.6, 128.5, 128.4, 128.2, 127.8, 126.7, 113.4, 80.9, 66.9, 62.8, 61.6, 59.6, 55.2, 54.2, 53.8, 50.0, 49.2, 48.4, 37.5, 36.8, 36.5, 34.3, 33.8, 31.7, 28.3, 26.2, 25.2,

[0172] 17.5. LC-MS (linear gradient 10 to 90% MeCN / HzO, 0.1% TFA, 12.5 min) Rt (min): 6.56 min (ESI-MS (m / z): 908.50 (M + H+)). mmol) with Boc-Glu(OBzl)-OH (21 mg;

[0173] 0.066 mmol) according to procedure B. Silica gel column chromatography (3% (v / v) MeOH / DCM) yielded the title compound (17 mg; 0.019 mmol; 57%) as a white powder after lyophilization.XH NMR (400 MHz, CDCh) 5 7.45 (d, J = 7 A Hz, 1H), 7.40 - 7.29

[0174] (m, 5H), 7.12 (d, J = 8.6 Hz, 2H), 6.81 (d, J = 8.6 Hz, 3H), 6.44 (d, J = 7.1 Hz, 1H), 5.12 (s, 3H), 4.93 (s, 1H), 4.62 - 4.48 (m, 2H), 4.41 (p, 7 = 7.1 Hz, 1H), 4.33 (d, J = 5.6 Hz, 1H), 4.19 (s, 3H), 4.10 (d, J = 12.2 Hz, 1H), 3.91 - 3.79 (m, 4H), 3.77 (s, 3H), 3.70 (t, J = 4.7 Hz, 4H), 3.37 (d, J = 4.9 Hz, 1H), 3.06 (d, J = 4.8 Hz, 1H), 3.00 (d, J = 7.2 Hz, 2H), 2.94 (s, 1H), 2.87 (d, J = 16.4 Hz, 1H), 2.44 (dd, J = 9.0, 4.8 Hz, 6H), 2.21 (dd, J = 13.5, 7.2 Hz, 1H), 2.03 - 1.83 (m, 4H), 1.80 - 1.50 (m, 6H), 1.43 (s, 9H), 1.36 (d, J = 7.1 Hz, 3H), 1.32 - 1.16 (m, 5H), 1.02 - 0.81 (m, 3H).13C NMR (101 MHz, CDCI3) 5 205.3, 171.9, 171.0, 170.3, 158.6, 157.0, 135.7, 130.4, 128.6,

[0175] 128.3, 128.3, 114.0, 66.9, 66.5, 63.3, 61.6, 59.6, 55.2, 54.2, 53.8, 52.8, 50.0, 49.4,

[0176] 48.4, 42.2, 37.5, 36.6, 34.3, 33.9, 31.7, 30.1, 29.7, 28.3, 27.7, 26.3, 26.2, 25.9,

[0177] 23.5, 17.7. LC-MS (linear gradient 10 to 90% MeCN / HzO, 0.1% TFA, 12.5 min) Rt (min) : 7.44 min (ESI-MS (m / z) : 922.33 (M + H+)). mmol) with Boc-Ser(OBn)-OH (21 mg; 0.066 mmol) according to procedure B. Silica gel column chromatography (3% (v / v) MeOH / DCM) yielded the title compound (33 mg; 0.037 mmol; quant.) as a white powder after lyophilization.1H NMR (400 MHz, CDCh) 6 7.45 (d, J = 7.4 Hz, 1H), 7.39

[0178] - 7.28 (m, 6H), 7.12 (d, J = 8.6 Hz, 2H), 6.81 (d, J = 8.6 Hz, 3H), 6.41 (d, J = 7.5 Hz, 1H), 5.39 (d, J = 8.8 Hz, 1H), 4.89 (d, J = 12.3 Hz, 1H), 4.61 - 4.47 (m, 5H), 4.46

[0179] - 4.36 (m, 2H), 4.25 (d, J = 7.9 Hz, 5H), 4.18 (d, J = 12.3 Hz, 1H), 3.84 (dq, J = 12.9, 6.5 Hz, 7H), 3.77 (s, 3H), 3.70 (t, J = 4.7 Hz, 4H), 3.30 (d, J = 4.9 Hz, 1H), 3.03 (d, J = 4.9 Hz, 1H), 3.00 (d, J = 6.8 Hz, 2H), 2.96 - 2.82 (m, 2H), 2.45 (q, J = 4.4 Hz, 4H), 1.78 - 1.49 (m, 6H), 1.45 (s, 10H), 1.36 (d, J = 7.1 Hz, 3H), 1.34 - 1.18 (m, 6H), 1.00 - 0.81 (m, 4H).13C NMR (101 MHz, CDCh) 5 205.3, 171.9, 170.9, 170.3, 170.0, 158.6, 157.0, 130.4, 128.5, 128.2, 127.9, 127.6, 114.0, 73.4, 69.9, 66.9, 63.0, 61.6, 59.7, 55.2, 54.2, 54.0, 53.8, 48.4, 42.1, 37.4, 36.6, 34.3, 33.9, 31.7, 28.3, 26.3, 26.2, 25.9, 23.5, 17.6. LC-MS (linear gradient 10 to 90% MeCN / HzO, 0.1% TEA, 12.5 min) Rt (min) : 7.45 min (ESI-MS (m / z) : 880.27 (M + H+)). mmo ) w oc ys( r ) ( mg; . mmol) according to procedure B. Silica gel column chromatography (3% (v / v) MeOH / DCM) yielded the title compound (39 mg; 0.037 mmol; quant.) as a white powder after lyophilization.XH NMR (400 MHz, CDCh) 6 7.42 (dd, J = 19.6, 7.2 Hz, 9H), 7.30 (d, J = 7.1 Hz, 6H), 7.25 - 7.19 (m, 4H), 7.11 (d, J = 8.7 Hz, 2H), 6.80 (d, = 8.6 Hz, 2H), 6.40 (d, J = 7.5 Hz, 1H), 4.97 (d, J = 8.2 Hz, 1H), 4.77 (d, J = 12.3 Hz, 1H), 4.58 (q, J = 7.0 Hz, 1H), 4.54 - 4.46 (m, 1H), 4.41 (p, J = 7.1 Hz, 1H), 4.23 (d, J = 7.2 Hz, 7H), 3.84 (dq, J = 13.0, 6.5 Hz, 6H), 3.76 (s, 3H), 3.73 - 3.64 (m, 4H), 3.29 (d, J = 5.0 Hz, 1H), 3.03 - 2.96 (m, 2H), 2.94 (s, 1H), 2.86 (d, J = 16.5 Hz, 1H), 2.61 - 2.41 (m, 6H), 1.78 - 1.48 (m, 6H), 1.43 (s, 10H), 1.41 (s, 3H), 1.36 (d, = 7.0 Hz, 4H), 1.31 - 1.16 (m, 7H), 1.03 - 0.79 (m, 3H).13C NMR (101 MHz, CDCh) 5 171.9, 170.9, 170.3, 158.6, 157.0, 144.2, 130.4, 129.5, 128.1, 128.0, 126.9, 126.8, 114.0, 66.9, 61.6, 59.5, 55.2, 54.2, 53.8, 52.4, 49.9, 48.4, 42.1, 37.6, 36.5, 34.3, 34.0, 33.8, 31.7, 30.0, 28.3, 27.9, 26.3, 26.0, 23.5, 17.6. LC-MS (linear gradient 10 to 90% MeCN / HzO, 0.1% TEA, 12.5 min) Rt (min) : 8.78 min (ESI-MS (m / z) : 1048.27 (M + H+)). mmol) with Boc-Pro-OH (14 mg; 0.066 mmol) according to procedure B. Silica gel column chromatography (3% (v / v) MeOH / DCM) yielded the title compound (22 mg; 0.027 mmol; 84%) as a white powder after lyophilization.1H NMR (400 MHz, CDCh) 5 7.42 (t, J = 8.1 Hz, 1H), 7.12 (d, J = 8.6 Hz, 2H), 6.80 (d, J = 8.6 Hz, 2H), 6.72 (d, J = 7.1 Hz, 1H), 6.31 (d, J = 7 A Hz, 1H), 4.85 (dd, J = 50.5, 12.2 Hz, 1H), 4.62 - 4.47 (m, 2H), 4.41 (td, J = 7.2, 4.6 Hz, 1H),

[0180] 4.25 - 4.17 (m, 1H), 3.99 (d, J = 12.2 Hz, 1H), 3.90 - 3.79 (m, 1H), 3.77 (s, 3H),

[0181] 3.70 (t, J = 4.6 Hz, 4H), 3.54 - 3.41 (m, 2H), 3.35 (dd, J = 25.1, 4.9 Hz, 1H), 3.06 (dd, J = 14.3, 4.9 Hz, 1H), 3.02 - 2.96 (m, 2H), 2.94 (d, J = 3.3 Hz, 1H), 2.86 (dd, J = 16.5, 7.2 Hz, 1H), 2.53 - 2.38 (m, 4H), 2.29 - 2.12 (m, 1H), 1.97 (ddd, J = 12.6,

[0182] 6.2, 4.3 Hz, 1H), 1.88 (p, J = 6.7, 6.2 Hz, 2H), 1.82 - 1.52 (m, 8H), 1.45 (d, J = 19.4 Hz, 9H), 1.39 - 1.19 (m, 7H), 1.06 - 0.82 (m, 3H).13C NMR (101 MHz, CDCh) 5 205.3, 172.4, 171.9, 170.9, 170.4, 158.6, 130.4, 128.2, 114.0, 80.1, 77.4, 77.0, 76.7, 66.9,

[0183] 63.2, 62.7, 61.6, 59.7, 59.1, 58.8, 55.2, 54.3, 53.8, 50.0, 49.2, 48.4, 46.5, 46.3,

[0184] 42.2, 37.5, 36.4, 34.4, 33.9, 31.7, 31.0, 29.9, 29.7, 28.5, 28.3, 26.3, 26.0, 24.4, 23.6, 23.5, 17.6, 17.4. LC-MS (linear gradient 10 to 90% MeCN / H2O, 0.1% TFA, 12.5 min) Rt (min) : 6.80 min (ESI-MS (m / z) : 800.13 (M + H+)). according to procedure A on a 0.013 mmol scale yielding the title compound (9.2 mg; 0.012 mmol;) as a white powder after lyophilization. LC-MS (linear gradient 10 to 90% MeCN / HzO, 0.1% TFA, 12.5 min) Rt (min) : 4.80 min (ESI-MS (m / z) : 674.33 (M + H+)). HRMS (ESI) m / z: [M + H+] calc for C34H51N5O9 674.37595, found 674.37600 accor ng o proce ure on a . mmo sca e yielding the title compound (5.25 mg; 0.006 mmol) as a white powder after lyophilization. LC-MS (linear gradient 10 to 90% MeCN / HzO, 0.1% TFA, 12.5 min) Rt (min) : 4.22 min (ESI-MS (m / z) : 702.33 (M + H+)). HRMS (ESI) m / z: [M + H+] calc for C36H55N5O9 702.41581, found 702.40814 yielding the title compound (8.7 mg; 0.010 mmol;) as a white powder after lyophilization. LC-MS (linear gradient 10 to 90% MeCN / HzO, 0.1% TFA, 12.5 min) Rt (min) : 5.21 min (ESI-MS (m / z) : 716.27 (M + H+)). HRMS (ESI) m / z: [M + H+] calc for C37H57N5O9 716.42882, found 716.42241 scale yielding the title compound (9 8 mg; 0.011 mmol;) as a white powder after lyophilization. LC-MS (linear gradient 10 to 90% MeCN / HzO, 0.1% TFA, 12.5 min) Rt (min) : 5.34 min (ESI-MS (m / z) : 750 33 (M + H+)). HRMS (ESI) m / z: [M + H+] calc for

[0185] C40H55N5O9 750.40725, found 750.40657 according to procedure A on a 0.018 mmol scale yielding the title compound (17 mg; 0.018 mmol;) as a white powder after lyophilization. LC-MS (linear gradient 10 to 90% MeCN / HzO, 0.1% TFA, 12.5 min) Rt (min) : 5.97 min (ESI-MS (m / z) : 826.33 (M + H+)). HRMS (ESI) m / z: [M + H+] calc for C46H59N5O9 826.43855, found 826.43831 . yielding the title compound (4.03 mg; 0.0048 mmol) as a white powder after lyophilization. LC-MS (linear gradient 10 to 90% MeCN / HzO, 0.1% TFA, 12.5 min) Rt (min) : 3.80 min (ESI-MS (m / z) : 717.25 (M + H+)). HRMS (ESI) m / z: [M + H+] calc for C35H52N6O10 717.38177, found 717.38202 p g p . mmol scale yielding the title compound (14 mg; 0.015 mmol) as a white powder after lyophilization. LC-MS (linear gradient 10 to 90% MeCN / HzO, 0.1% TFA, 12.5 min) Rt (min) : 5.51 min (ESI-MS (m / z) : 808.40 (M + H+)). HRMS (ESI) m / z: [M + H+] calc for C42H57N5O11 808.41273, found 808.41203 per orme accor ng to proce ure on a . mmol scale yielding the title compound (12 mg; 0.012 mmol) as a white powder after lyophilization. LC-MS (linear gradient 10 to 90% MeCN / H2O, 0.1% TFA, 12.5 min) Rt (min) : 5.47 min (ESI-MS (m / z) : 822.33 (M + H+)). HRMS (ESI) m / z: [M + H+] calc for C43H59N5O11 822.42838, found 822.42800 performed according to procedure A on a 0.011 mmol scale yielding the title compound (8.7 mg; 0.010 mmol) as a white powder after lyophilization. LC-MS (linear gradient 10 to 90% MeCN / H2O, 0.1% TFA, 12.5 min) Rt (min) : 5.51 min (ESI-MS (m / z) : 780.40 (M + H+)). HRMS (ESI) m / z: [M + H+] calc for C41H57N5O10 780.41782, found 780.41751 performed according to procedure A on a 0.009 mmol scale yielding the title compound (24 mg; 0.0226 mmol) as a white powder after lyophilization. LC-MS (linear gradient 10 to 90% MeCN / HzO, 0.1% TEA, 12.5 min) Rt (min) : 4.88 min (ESI-MS (m / z) : 948.27 (M + H+)). HRMS (ESI) m / z: [M + H+] calc for C53H65N5O9S 948.45758, found 948.45715 accor ng to proce ure on a . mmo sca e yielding the title compound (11 mg; 0.013 mmol) as a white powder after lyophilization. LC-MS (linear gradient 10 to 90% MeCN / H2O, 0.1% TEA, 12.5 min) Rt (min) : 4.84 min (ESI-MS (m / z) : 700.33 (M + H+)). HRMS (ESI) m / z: [M + H+] calc for C36H52N4O9 700.39160, found 700.39127 two times and subsequently dissolved in anhydrous DCM (0.1 M) and purged with N2. To this solution were added isobutyric anhydride (8.3 pL, 0.05 mmol 2.0 eq.) and DMAP (3.0 mg, 0.025 mmol, 1.0 eq.). The resulting reaction mixture was left stirring for two hours and subsequently concentrated in vacuo. Silica gel column chromatography (0% -> 3% (v / v) MeOH / DCM) yielded the title compound (7.03 mg, 10.46 pmol) as a white powder after lyophilization. HRMS (ESI) m / z: [M + H+] calc for C35H52N4O9 673.38071, found 673.38071 mmol) according to procedure B. Silica gel column chromatography (3% (v / v)

[0186] MeOH / DCM) yielded the title compound (15,46 mg, 0.020 mmol) as a white powder after lyophilization. HRMS (ESI) m / z: [M + H+] calc for C4oH64N40ioSi 789.44645, found 789.44607 yielding the title compound (9.64 mg, 0.014 mmol) as a white powder after lyophilization. HRMS (ESI) m / z: [M + H+] calc for C34H50N4O 10 675.35997, found

[0187] 675.35945 mg; 0.066 mmol) according to procedure B. Silica gel column chromatography (3%

[0188] (v / v) MeOH / DCM) yielded the titled compound (21 mg; 0.025 mmol; 78%) as a white powder after lyophilization. 1H NMR (400 MHz, CDCI3) 5 7.43 15 (d, J = 7.7 Hz, 1H), 7.10 (d, J = 7.7 Hz, 2H), 6.81 (dd, J = 17.1, 8.1 Hz, 3H), 6.71 (s, 1H), 5.03 (d, J = 12.2 Hz, 1H), 4.62 (d, J = 8.4 Hz, 2H), 4.54 (d, J = 8.6 Hz, 1H), 4.41 (p, J = 7.1 Hz, 1H), 4.13 (d, J = 7.4 Hz, 2H), 3.91 - 3.79 (m, 3H), 3.77 (s, 3H), 3.69 (t, J = 4.6 Hz, 4H), 3.37 (d, J = 4.9 Hz, 1H), 3.18 (p, J = 7.0 Hz, 1H), 3.04 (d, J = 4.8 Hz, 2H), 3.00 (d, J = 7.2 Hz, 1H), 2.95 (s, 1H), 2.87 (d, J = 16.4 Hz, 1H), 2.45 (q, J 20 = 4.1 Hz, 4H), 2.33 (q, J = 8.6, 8.0 Hz, 2H), 1.84 (d, J = 19.8 Hz, 3H), 1.76 - 1.55 (m, 7H), 1.45 (s, 12H), 1.35 (d, J = 7.0 Hz, 4H), 1.33 - 1.16 (m, 8H), 1.08 - 0.80 (m, 3H). 13C NMR (101 MHz, CDCI3) 5 172.7, 171.7, 171.2, 158.6, 157.0, 130.5, 128.0, 113.9, 66.9, 63.1, 61.7, , 55.2, 53.8, 49.0, 42.2, 40.5, 36.8, 34.0, 31.7, 30.0, 28.5, 26.3, 26.2, 26.0, 25.9, 24.5, 23.5, 17.8. LC-MS (linear gradient 10 to 90% MeCN / H2O, 25 0.1% TFA, 12.5 min) Rt (min): 7.05 min (ESI-MS (m / z): 816.20 (M + H + )).

[0189] NHBoc was performed according to procedure A on a 0.025 mmol scale yielding the titled compound (12 mg; 0.014 mmol; 56%) as a white powder after lyophilization. LC-MS 5 (linear gradient 10 to 90% MeCN / H2O, 0.1% TFA, 12.5 min) Rt (min): 5.10 min (ESI- MS (m / z): 716.40 (M + H + )). in profiling proteasome inhibition

[0190] The biological activity of compounds 1-27 was assessed using a competitive activitybased protein profiling assay.

[0191] Activity-based protein profiling (ABPP) has been used for the past three decades to detect and identify enzymes from complex biological samples. In ABPP, activity-based probes (ABPs), which contain substrate-like elements connected to (in most cases) an electrophile and endowed with a reporter moiety (biotin, a fluorophore or a bioorthogonal tag), react within the active site of the target enzyme, or enzyme family to form a covalent and irreversible bond. Several proteasome inhibitors (peptide vinyl sulfones, peptide epoxyketones) react in a mechanism-based fashion, making them good starting points for the design of proteasome-targeting ABPs. Eventually a set of three ABPs were developed, that when combined are able to resolve all six human cCP and iCP active subunit, after running ABP-treated cell lysates on an SDS-PAGE gel followed by in-gel fluorescence detection. With this ABPP assay cell lysates can be rapidly analyzed for their cCP and iCP catalytic activity content composition. For instance, treatment of lysates of Raji cells, a B-cell lymphoma cell line that constitutively express both proteasome isoforms, with the three ABPS followed by SDS PAGE, and in-gel fluorescent detection yields six bands that correspond to all six iCP and cCP active sites.

[0192] Competitive ABPP is complementary to comparative ABPP and allows the identification of active compounds, as well as their selectivity and potency, of libraries of putative proteasome inhibitors. Since most proteasome inhibitors designed in the literature, and the examples described in this text, are peptide-based electrophiles that react within proteasome active sites to form a covalent and irreversible bond or form a long-lasting complex. In competitive ABPP, individual inhibitors are added at various concentrations and for varying time to a cell lysate (or a cell in case cell permeability is investigated) prior to addition of the three ABPs, SDS PAGE and in-gel fluorescence scanning. In this way the selectivity and activity of the panel of putative proteasome inhibitors depicted in example 1 were determined in the following way. Lysates of cells were prepared by treating cell pellets with an addition of two volumes of lysis buffer, containing 250 mM sucrose, 50 mM Tris pH 7.5, 2 mM DTT, 5 mM MgCh, 10% (v:v) glycerol, 2 mM ATP, 0.05% (w:v) digitonin and 25 U / rnl benzonase, resting for one hour on ice, followed by centrifuging for 15 minutes at 15 °C on 22000 ref. Protein concentrations were then determined using a Bradford assay, followed by diluting cell lysates with assay buffer.

[0193] Cell lysates were diluted to 1.4 - 2.0 pg / pL total protein in an assay buffer containing 50 mM Tris pH 7.5, 2 mM DTT, 5 mM MgCI2, 10% glycerol and 2 mM ATP. Cell lysates were then exposed to an inhibitor dilution series (30 pM, 10 pM, 3 pM, 1 pM, 0.3 pM, 0.1 pM, 0.03 pM, 0.01 pM, 0.003 pM diluted in DMSO) for one hour at 37 °C. Additionally, inhibited cell lysates were exposed to a probe cocktail (Cy2: BODIPY(FL)- LU-112, Cy3: BODIPY(TMR)-NC-005VS, Cy5: Cy5-NC-001) for one hour at 37 °C. Next, cell lysates were denatured addition of a reducing gel loading buffer and boiling at 95 °C for four minutes. Subsequently, denatured cell lysates were loaded on a 12.5% SDS-PAGE gel and fractioned through gel electrophoresis for 90 minutes at 160 V. Directly after electrophoresis, multiplex fluorescent detection of residual activity-based probes was performed on a ChemiDoc™ MP System with Cy5, Cy3 and Cy2 channels. The gel was then fixed and stained in Coomassie Blue Stain overnight, followed by destaining in demineralized water for two days. Likewise, Coomassie blue detection was performed on the ChemiDoc™ MP system and transformed in Image Lab Adjusted intensities of fluorescent bands were transformed with Image Lab. The normalized adjusted volume was plotted against inhibitor concentrations and then the ICso values per inhibitor were calculated using GraphPad Prism 9.0 software (using a non-linear regression, [Inhibitor] vs. normalized response with a variable slope, model).

[0194] For / V-Boc amino acid esters 3-13 weak to no inhibition was observed for any of the cCP active sites. When comparing compounds 3-13 to LU-005i, LU-005i revealed as quite potent for B5c in comparison to the other proteasomal subunits. The low potency observed for Bic and B2c, of the compounds found in Figure 1, is corroborated by the data found during the development of LU-005i, where it was determined that affinity for Bic and B2c was suppressed through the Pl and P2 residue combination; Tyr(OMe)- Cha. All / V-Boc esters shown in Figure 1 showed a decrease in potency for B5c of at least 1.5-fold compared to LU-0051 1. Additionally, LU005i-OH 2, / V-Boc alanine 3, / V- Boc asparagine 8, / V-Boc aspartic acid 9, / V-Boc glutamic acid 10, / V-Boc serine 11, / V- Boc proline 13, alanine-ZW-fe 12, valine- / V / 72 13, isoleucine- / V / 72 16, aspartic acid-Nf-fo 20 and cysteine- / V / 72 23 all display an iCP selective character. Out of the proteasome inhibitors listed above LU-005i-OH 2, / V-Boc alanine 3, / V-Boc aspartic acid 9, / V-Boc glutamic acid 10, alanine- / V / 72 14, aspartic add-NH? 20, serine- / V / 72 22 and cysteine- NH2 23 are the most interesting as they all have a ratio of two-fold and up of selectivity for the iCPs over cCPs (highest cCP potency versus lowest iCP potency).

[0195] None of the compounds featuring an aliphatic and large amino acid ester ( / V-Boc valine 4, / V-Boc isoleucine 5, / V-Boc phenylalanine 6, / V-Boc diphenylalanine 7 and / V-Boc-S- Trt cysteine 8) showed any potency for Bli and B2i suggesting that the size of the amino acid residues on Pl' negatively impacts affinity for these subunits. Coincidently, this makes the compounds mentioned above very selective B5i inhibitors. In contrast to what was found for / V-Boc phenylalanine 6, / V-Boc diphenylalanine 7 and / V-Boc-S- Trt cysteine 8, / V-Boc aspartic acid 9, / V-Boc glutamic acid 10 and / V-Boc serine 11 proved to be potent inhibitors for Bli and B2i. Possibly, the rotational flexibility and hydrogen bonding capability found in the benzylated carboxylic acids of / V-Boc aspartic acid 9 and / V-Boc glutamic acid 10 and the benzylated hydroxyl of / V-Boc serine 11 offsets clashes in the S' pocket. Additionally, an increase in potency for Bli, B2i and B5c was observed when comparing / V-Boc serine 11 with / V-Boc aspartic acid 9, and as well an additional increase in potency fo Bli, B2i and B5c was observed when com / V- Boc aspartic acid 9 with / V-Boc glutamic acid 10. Interestingly, when comparing / V-Boc aspartic acid 9 with / V-Boc asparagine 7 a similar inhibition profile was observed. Out of the / V-Boc amino acid ester proteasome inhibitors, / V-Boc alanine 3 proved to be the sole inhibitor that showed potencies of 10 pM or higher for each of the cCP active sites, in conjunction with potencies of 4 pM or lower for the iCP ones (Figure 1). When comparing / V-Boc alanine 2 to the branched alkyl derivatives / V-Boc valine 4 and / V-Boc isoleucine 5 it can be postulated that such residues decrease affinity for the Bli and B2i subunits.

[0196] Overall, an increase in potency for Bli and B2i was observed for all NH2 amino acid esters found in Figure 1 when comparing them with their / V-Boc counterparts (3-13). All NH2 amino acid esters, except phenylalanine- / V / 72 17, diphenylalanine- / V / 72 18, glutamic acid- / V / 72 19, serine- / V / 72 20 and proline- / V / 72 24, showed potencies equal to or higher than 10 pM for Bic and B2c. Removing the / V-Boc protective group introduces two structural changes, namely: significant reduced steric bulk, and a hydrophilic amine, which is protonated at physiological pH. Valine- / V / 72 15, isoleucine- / V / 72 16, phenylalanine-ZW-fe 17 and diphenylalanine-ZW-fe 18 showed increased affinity for Bli, B2c, B2i and B5c. This suggests that the combination of an / V-Boc protective group with branched alkyl or bulky aromatic residues abolishes inhibition of Bli, B2c, B2i and B5c. When comparing glutamic acid-Nf-fo 21 and serine- / V / 72 22 with their / V-Boc counterparts, an increase in potency for Bli, B2c, B2i, B5c, B5i was observed. Interestingly, serine- / V / 72 22 proved to be a potent inhibitor for Bli, B2c, B2i, B5c and B5i, while its / V-Boc counterpart was only potent for B5i. Moreover, glutamic acid-NH? 21 showed no iCP selectivity, turning out to be a potent inhibitor of Bli, B2i, B5c and B5i. Aspartic add-NH? 20 was the only inhibitor of the three O-benzyl protected inhibitors (20-22) that showed a selectivity for iCPs over cCPs, when comparing the three to their N-Boc counterparts (9-11).

[0197] Strikingly, cysteine- / V / 72 23, which is similar in sidechain length as serine- / V / 72 22 and bearing an aromatic protective group, albeit a much larger protective group compared to a benzyl protective group, did prove to be an iCP selective inhibitor, while its / V-Boc counterpart (12) was not. Alanine- / V / 72 14 showed increased selectivity for iCPs with a ten-fold increase in potency for both Bli and B2i and a five-fold increased potency for B5c when comparing to / V-Boc alanine 3. Altogether these studies identified alanine- NH2 14 as the most selective inhibitor of all three iCPs of all compounds tested.

[0198] Alanine- / V / 72 14 thus emerged as the best iCP selective proteasome inhibitor, and to further probe this, alanine- / V / 72 14, together with / V-Boc alanine 3 were reassessed and compared to 25, 26 and 27 in a competitive ABPP assay in a larger concentrations range (up to 30 pM, Figure 2).

[0199] All alanine isomers shown in Figure 2 feature an increased selectivity for iCP active subunits over cCP active subunits in comparison to the inhibitors depicted in Figure 1. When comparing O-TBS lactic acid 26 with / V-Boc alanine 14, a decrease in potency was observed for B2i for the former, suggesting that the increase in steric bulk of the TBS protective group is disfavoured by B2i. Dissimilar to alanine- / V / 72 14, lactic acid- OH 27 did not show an increased potency for B2c and B5c. In addition, lactic acid 27 also did not show an increase in potency for Bli and B2i as observed for alanine- / V / 72 14 when both are compared with their protective group counterparts (26 and 3). Interestingly, an eight-fold decrease in potency for Bli was observed for lactic acid 27 when compared to O-TBS lactic acid 26. Isobutyric acid 25 showed a similar inhibition profile as / V-Boc alanine 2, with an iCP selective inhibition profile. Size-wise, isobutyric acid 25 and lactic acid 27 are comparable to alanine 13, while their inhibition profiles are not. This suggests that N-terminal steric bulk is not the main determinant for potency and selectivity, but rather the atomic properties of the N-terminal atom. Overall, no clear trend was observed regarding size of the non-amine containing isomers.

[0200] Reference Examples 3 - esis of com 28 to 51 (P3 varia

[0201] Compounds 28-51 as shown below have been synthesized by methods analogous to those described in Example 1 and the method below for compound 28.

[0202] P3 alterations

[0203] Compounds are named according to the abbreviations of the P4 and P3 sites. For instance, compound 28 is Mor(P4)-Gly(P3)-Tyr(OMe)(P2)-Cha(Pl)-EK, and it is abbreviated as 28 (Mor-Gly).

[0204] The synthesis of compound 28

[0205] ^Reagents and conditions: (a) Boc-Gly-OH, HCTU, DiPEA, DCM, 17%; (b) (i) TEA, DCM, quant, (ii) Morpholinoacetic acid, HCTU, DiPEA, DCM, 48%; (c) Hydrazine hydrate, MeOH, quant.; (d) (i) tBuONO, HCI, DMF, -30 °C; (ii) 97, DiPEA, 13%. Reference Example 4 - Synthesis of compounds 52 to 57 (P3 variants)

[0206] Compounds 52 to 57 as shown below have been synthesized by methods analogous to those described in Example 1 and the method above for compound 28

[0207] Reference Example 5 -

[0208] The biological activity of compounds 28-57 was assessed using the biological assay described in Example 2. The resulting apparent ICso values were plotted in the heatmap shown in Figure 3.

[0209] Based on its moderate pan-immunoproteasome selectivity we selected LU-005i 1 as our lead compound. The C-terminal epoxyketone, the cyclohexyl-l-alanine (Cha) residue at position Pl and the Tyr(OMe) residue at P2 were kept fixed in our designs, because these structural elements have previously been shown to be accepted by all iCP activities. The P3 and P4 ( / V-cap) residues were varied with the aim to arrive at compounds with increased iCP selectivity, by virtue of an increased activity against the iCP activities, by reduced activity against the cCP ones or by a combination of both. Based on this rationale, we created a first set of in total 24 peptide epoxyketones (compounds 28-57) having the general structure Y-X-Cha-Tyr(OMe)-epoxyketone, with Y being one out of five tested N-caps and X one of five selected alpha-amino acids. Because pii and P5i subunits both feature smaller S3 pockets compared to their constitutive counterparts, four relatively small P3 residues were chosen, namely, Gly, Ala, Ser, and 2-aminoisobutyric acid (Aib). As a control for the influence of small P3 residues on activity and selectivity, we selected the large O-benzyl-Ser (Ser(OBn)). As P4 moieties, we used the morpholine (Mor) cap (also present in LU-005i 1), piperazine (HPip), / V-methylpiperazine (MePip), tert-butyloxycarbonyl-protected piperazine ( / V- BocPip) and 4-hydroxylcyclohexyl (HCH). The syntheses of all 24 compounds were performed according to previously established protocols. As an example, the route of synthesis towards compound 28 as depicted above (see experimental section for details on the synthesis and characterization of all compounds). The proteasome inhibition potency and selectivity of the resulting 24 compounds was assessed in competitive activity-based protein profiling (ABPP) assays and compared to that of LU- 005i 1. This technique utilizes three selective activity based probes that label the 02c / i subunits (appears as a green color), the 05c / i subunits (appears as a red color) and the pic / i subunits (appears as a blue color), evaluating the inhibition profile of all catalytic activities of cCP and iCP. Extracts from Raji cells, a human B-cell lymphoma cell line, were used as they express both iCPs and cCPs and compounds 28-57 were tested in a dilution series (final concentrations 0.01 pM to 100 pM). In brief, cell extracts were treated with inhibitor, followed by the three ABPs. The samples were then separated by SDS-PAGE and in-gel scanning was performed to detect any remaining fluorescence. Apparent ICso values were derived and plotted as heat maps (Figure 3). The results revealed that all compounds are poor pic and 02c inhibitors, corroborating previous work showing that the Tyr(OMe)-Cha-epoxyketone scaffold interferes with pic and 02c inhibition. Compounds 50 (HCH-Ser(OBn)), 45 (MePip- Ser(OBn)) and 34 (BocPip-Ser) appeared to be the most potent 01i inhibitors and significantly outperformed LU-005i 1 as well as all other compounds with Ala, Gly or Aib at P3. Surprisingly the bulky P3-Ser(OBn) featuring compounds 45 and 50 showed high potency, although we initially did not expect these inhibitors to fit the small size of the pii-S3 cavity. Notably, the data also revealed that large side chains are possible at either P3 or P4 but not favorable at both positions. For instance, compounds 35 (BocPip-Ser(OBn)) and 40 (HPip-Ser(OBn)) were less potent for pi i.

[0210] Subsequently, we examined the 24 compounds plus LU-005i (1) for their 02i potencies. The results clearly pointed towards 34 (BocPip-Ser) as the most effective and selective epoxyketone of the series, whereas compounds having a Ser(OBn) at P3 proved to be poor 02i inhibitors compared to the corresponding l-Ser derivatives.

[0211] Finally, the inhibition potencies for 5c and 05 i subunits were analyzed. The most active 05i inhibitors turned out to be compounds 34 (BocPip-Ser) and 35 (BocPip-Ser(OBn)). While compound 35 showed only minor selectivity for 05i (3-fold), compound 34 proved much more selective for 05i (21-fold). Due to an Ala27 to Ser substitution (constitutive proteasome vs immunoproteasome), the S3 pocket at the P5i active site is comparatively smaller than that in the 5c subunit, which may explain the better performance of 34 with the sterically less demanding Ser residue. Altogether, in terms of potency and selectivity, compound 34 proved to be the most effective compound of the series: it inhibits each of the immunoproteasome active activities potently (ICso values for i-subunits < 0.84 pM) and with considerable selectivity over the constitutive proteasome counterparts (IC50 ratio pic / pii : 36, 02c / 02i: 33, 5c / 5i: 7).

[0212] Second-generation focused library

[0213] Based on 34 a next set of compounds was designed, synthesized and evaluated (52- 57. All compounds of this series share the general structure Boc-Pip-X-Cha-Tyr(OMe)- epoxyketone, combining the C-terminal dipeptide epoxyketone of LU-005i 1 with the P4 residue as present in lead compound 12. As P3 substituents we selected amongst others Arg (as in 52), carboxybenzyl (Cbz)-protected Arg 53 and O-p-xylol (OpXyl, 54). Furthermore, the respective P3 diastereomers of 34 and 35, BocPip-d-Ser 55 and BocPip-d-Ser(OBn) 56 were included, because d-amino acids at P3 have previously been described to enhance 05i selectivity in respect to their l-amino acid counterparts in epoxyketone inhibitors. In addition, compound 57, carrying a pyrimidine protected Lys side chain at P3, was included as an arginine mimic. Compounds 52-57 were assayed by competitive ABPP and activities were scored and plotted as before for all constitutive proteasome and immunoproteasome active sites. Although several compounds showed activity at low concentrations for all immunoproteasome activities, most of them co-inhibited the 05c active site, making them less attractive than lead compound 34. As expected, peptide epoxyketones featuring a d-amino acid at P3 proved to be poor 05c inhibitors, but unfortunately turned out to be weak 01 i and 02i inhibitors as well. This 05i selectivity was previously noted and most probably results from steric factors associated with the kinked binding mode induced by P3 d-amino acids.

[0214] Reference Example 6 - Synthesis of compounds 58 to 77 (P3 variants)

[0215] Compounds 58-77 as shown below have been synthesized by methods analogous to those described in Examples 1 and 3. Further synthetic details are provided below.

[0216] Compounds are named according to the abbreviations of the P4 and P3 sites.

[0217] A library of novel compounds was designed containing a serine on P3 and BocPip or Morph on P4. Modifications were made in an attempt to improve the selectivity of B5i over B5c. Amino acids and derivatives thereof that were used include: Diaminopropionic acid (Dap), Homoserine (Hser), Diaminobutanoic acid (Dab), Asparagine (Asn), Pentahomoserine (HHSer) and Glutamine (Gin).

[0218] All peptide epoxyketones presented in Figure 4 feature a cyclohexylalanine epoxyketone at Pl and thus as substantial amount of 97 was synthesized. Condensation of / V-Boc cyclohexylalanine 77 with Weinreb salt afforded Weinreb amide 78 (Scheme 3). Then, bromopropene was carbolithiated, and the resulting propenyl lithium was added onto Weinreb amide 78 affording the a,B-unsaturated-ketone 98. Nucleophilic epoxidation using hydrogen peroxide yielded both diastereomers of epoxide 99, which after silica gel column chromatography was isolated to give / V-Boc epoxyketone 99. Finally, the / V-Boc protective group in 99 was removed using TFA affording epoxyketone 97.

[0219] Scheme 3. The synthesis of a cyclohexyl alanine epoxyketone 97. Reagents and conditions: (a) HCI*HNMeOMe, HCTU, DiPEA, DCM, rt, 90%; (b) i: bromopropene, tBuLi, THE, -78 °C; ii: 78, THE, -78 °C 70%; (c) H2O2, DiPEA, benzonitrile, MeOH, 0 °C, 50%; (d) TEA, DCM, rt, quant.

[0220] 5

[0221] Having large amounts of epoxyketone 97 in hand attention was focused on the construction of the various N-terminal P2-P3-P4 fragments that combined would yield the target library. For this purpose a variety of amino acid featuring at P3 needed to be prepared and appropriately functionalized to make them compatible with peptide synthesis chemistries. For the synthesis of partially and orthogonally protected diaminopropionic acid for ensuing incorporation at P3, / V-Boc asparagine 100 was rearranged via a Hoffman rearrangement using diacetoxyiodobenzene (PIDA) as the oxidating agent to form / V-Boc diaminopropionic acid (Dap) 102 (Scheme 4). Next, the / V-B of Dap 102 was protected with an Alloc group (102 to 104), and / V-Alloc Dap

[0222] 15 104 was then coupled to 4-methoxyphenylalanine yielding dipeptide 106. De- / V- Bocylation of 106, followed by condensation with 2-morpholinoacetic acid yielded ester 108, which was then converted into acyl hydrazide 110, followed by conversion into the acyl azide intermediate, by using tert-butyl nitrite under anhydrous acidic conditions. Upon formation of the acyl azide intermediate, as followed by LC-MS, the pH was neutralized using DiPEA, after which epoxyketone 97 was added forming the P3 / V-Alloc Dap equipped target compound 58. Palladium-catalysed removal of the / V- Alloc protective group in 58 using a catalytic amount of Pd(PPhs)4 and phenyl silane as an allyl-scavenger, yielded the P3 / V / 72Dap target compound 59. Finally, compound 59 was acetylated using acetic anhydride in pyridine, yielding 60. The synthesis as

[0223] 25 described above was repeated and executed with glutamine as starting material to synthesis the diaminobutanoic acid (Dab) derivatives 61, 62 and 63 (Scheme 4).

[0224] Scheme 4. Synthesis of P3 modified LU-005i based proteasome inhibitors. Reagents and conditions: (a) PIDA, THF:H2O 1 : 1, 0 °C; (b) Alloc-OSu, pyridine, DCM, rt, 104: 94%, 105: 90% (c) i: TFA, DCM, rt, ii: TFA»NH2-Tyr(OMe)-OMe, HCTU, DIPEA, DMF, rt, 106: 54%, 107: 80%; (d) i: TFA, DCM, rt, ii: 2-morpholinoacetic acid, HCTU, DIPEA, DMF, rt, 108: 78%, 109: 77%; (e) hydrazine hydrate, MeOH, rt, quant, (f) i: tBuONO, HCI, DMF, -30 °C, ii: 97, DiPEA, DMF, -30 °C -> rt, 58: 54%, 61: 32%; (g) Pd(PPhs)3, phenylsilane, DCM, 0 °C, 59: 43%, 62: 64%; (h) Ac2O, pyridine, DMF, rt, 60: 93%, 63: 95%.

[0225] For the synthesis of compounds 64-67, the carboxylic acid side chain of aspartic acid 112 was activated using isobutylchloroformate and in the presence of / V- methylmorpholine (pKa 7.38) as a proton scavenger. Use of stronger bases, as proton scavengers, such as triethylamine (pKa 10.75) led to the formation of side products. Following formation of the isobutyl anhydride intermediate, sodium borohydride was added to reduce the anhydride intermediate to homoserine (HSer) derivative 114 (Scheme 5). The benzyl ester in 114 was then saponified using lithium hydroxide affording carboxylic acid 116. Consecutively, by using two equivalents of sodium hydride to deprotonate the carboxylic acid and alcohol, followed by addition of one equivalent of benzyl bromide O-Bn homoserine 118 was obtained. Carboxylate 118 was then condensed with 4-methoxy phenylalanine methyl ester forming / V-Boc dipeptide 120. / V-Boc dipeptide 120 was then de-N-Bocylated using TFA in DCM and the resulting free amine condensed with 2-morpholinoacetic acid to afford ester 122. The ester in 122 was then saponified using lithium hydroxide in an equal mixture of H2O and methanol yielding carboxylic acid 124. Compound 124 was then condensed with epoxyketone 97 using PyBOP as a peptide coupling reagent to form the O-Bn HSer compound 64. Removal of the O-Bn protective group through hydrogenation using Pd on carbon under a hydrogen saturated atmosphere yielded the OH HSer compound 65. In order to synthesize HSer compounds 69 and 70, instead of 2-morpholinoacetic acid / V-Boc piperazinyl was condensed with de- / V-Bocylated dipeptide 120, after which the synthesis route was executed as described above. In a similar vein, the synthesis route described above was repeated using / V-Boc glutamic acid 113 to afford the O-Bn pentahomoserine (HHSer) target compounds 66 and 71 and the P3 OH HHSer target compounds 67 and 72.

[0226] Scheme 5. Synthesis of P3 and P4 modified LU-005i based proteasome inhibitors. Reagents and conditions: (a) i: isobutyl chloroformate, NMM, THF, 0 °C, ii: NaBH4, MeOH 0 °C -> rt, 114: 81%, 115: 71%; (b) LiOH, H2O / MeOH 1: 1, rt, quant, (c) NaH, BnBr, DMF, 0 °C -> rt, 118: 62%, 119: 59%; (d) i: TFA, DCM, rt, ii: TFA®NH2- Tyr(OMe)-OMe, HCTU, DIPEA, DMF, rt, 120: 26%, 121: 29%; (e) : TFA, DCM, rt, ii: 2-morpholinoacetic acid, HCTU, DIPEA, DMF, rt, 122: 75%, 123: 84%; (f) : TFA, DCM, rt, ii: / V-Boc piperazinyl-acetic acid, HCTU, DIPEA, DMF, rt, 126: 83%, 127: 93%; (g) LiOH, H2O / MeOH 1 : 1, rt, quant.; (h) 97, PyBOP, NMM, DMF, rt, 64: 91%, 65: 84%, 69: 88%, 71: 70%; (i) Pd / C, H2, MeOH, rt, 65: 85%, 67: 84%, 70: 75%, 72: 95%.

[0227] For the construction of the final target compounds of the focused library, compounds 68 and 73, / V-Boc asparagine (Asn) was condensed with 4-methoxyphenylalanine forming the Asn dipeptide 132 (Scheme 6). De- / V-Bocylation of 132 using TFA in DCM, followed by condensation with 2-morpholinoacetic acid yielded methyl ester 134, which was then converted into acyl hydrazide 136 by treatment with hydrazine hydrate. Acyl hydrazide 136 was then converted into the corresponding acyl azide intermediate 138, by using tert-butyl nitrite under anhydrous acidic conditions after which epoxyketone 97 was added forming the P3 Asn derivative 68. Additionally, the synthesis route as described above was repeated using / V-Boc glutamine (Gin) to afford the P3 Gin derivative 73. Of note, when preparing methyl ester 134 through condensation of dipeptide 132 with 2-morpholinoacetic acid successful conversion was only observed upon pre-activation of 2-morpholinoacetic acid with HCTU. All other attempts resulted in the formation of the glutamine guanidinium adduct as a major product in the reaction.

[0228] Scheme 6. Synthesis of P3 analogues of LU-005i. Reagents and conditions: (a) TFA®NH2-Tyr(OMe)-OMe, HCTU, DIPEA, DMF, rt, 132: 82%, 133: 82%; (b) : TFA, DCM, rt, ii: 2-morpholinoacetic acid, HCTU, DIPEA, DMF, rt, 134: 88%, 135: 35%; (c) hydrazine hydrate, MeOH, rt; (d) i: tBuONO, HCI, DMF, -30 °C, ii: 97, DiPEA, DMF, - 30 °C -> rt, 68: 36%, 73: 42%.

[0229] Reference Example 7 - Competitive ABPP assay in Raji cell lysate

[0230] The biological activity of the compounds of Example 6 was assessed using the biological assay described in Example 2.

[0231] The resulting apparent ICso values were plotted in the heatmap shown in Figure 4.

[0232] The potency and selectivity profiles for all compounds described in Figure 4 as proteasome inhibitors were determined using a competitive ABPP assay, in Raji cell lysates (B-cell lymphoma cell line that expresses both cCPs and iCPs). Compounds 58- 73 were tested in a concentration series ranging from 0.003 pM to 30 pM to determine the apparent inhibitory concentration (ICso) for each catalytically active proteasome subunit. The resulting apparent ICso values were plotted as heat maps as shown in Figure 4. Using the heat maps an initial structure-activity relationship (SAR) can be determined for the library of LU-005i analogues and the relation between the P3 and P4 substituents and cCP / iCP inhibition profiles.

[0233] In assessing the inhibitory potency of the pane of compounds, two sets of compounds were deemed of interest: those that show high potency against all three iCP subunits, and those whose potency for these activities is less pronounced, but selectivity over the corresponding cCP activities is high. Morph-HSer derivative 65, Morph-Asn derivative 68 and BocPip-HSer derivative 70 all three fit within one of the two compound classes as described above. All three feature a P3 residue that is identical in length from the alpha carbon up to the side chain functionality. Both Morph-Asn 68 and BocPip-HSer 70 display strong potency for the iCP subunits, outperforming LU- 005i 1 in this feat. Morph-HSer 65 on the other hand outperformed Morph-Ser 28, but displayed a similar inhibition profile when compared to LU-005i 1. More importantly, Morph-HSer 65 proved to be the proteasome inhibitor with the strongest selectivity for iCPs over the cCPs.

[0234] None of the proteasome inhibitors featuring a Dap or Dab at P3 outperformed LU-005i 1 or improved upon the previously screened inhibitors 28 and 30. Compounds 58 and 60 showed lower potency for Bic and B2c but a five-fold increase in potency for B5c when compared to LU005i 1, while compounds 59 and 62 proved to be comparatively less potent Bli inhibitors. The basic NH? of Dap 59 and Dab 62, which is protonated at pH 7, is most likely incompatible with the S3 binding pocket of Bli. Surprisingly, the comparative (to LU-005i) decrease in inhibitory potency found for 62 was not matched by 65, corroborating that the charged amine rather than the increased carbon length causes the decrease in potency. Compound 60 proved to be a weak inhibitor for both Bl and B2i when compared to compound 59, coincidently making it a highly selective B5i inhibitor. Overall introduction of Dap or Dab on P3 did not result in compounds featuring the desired combined increase in potency for Bli and B2i and decrease in potency toward B5c.

[0235] Previously conducted structure activity relationship studies revealed compound 30 to be a poor inhibitor of all proteasome active sites Bli, Bic, B2i, B2c, B5i and B5c. Perhaps counterintuitively, both analogues 64 and 66, featuring a benzylated homoserine instead of a benzylated serine (as in 30) proved to be more potent for Bli, B2i, B5c and B5i inhibitors when compared to 28. Additionally, when comparing benzylated analogues 64 and 66 with their OH counterparts 65 and 67, 70 and 72 proved to be more potent for Bli, B2i and B5c. However, when looking at the ratio between lowest cCP inhibition versus highest iCP inhibition, compound 65 appeared to outperform compound 2. For the compounds featuring an asparagine or a glutamine at P3, unexpected inhibition profiles were obtained. Intuitively, it would be expected that asparagine and glutamine would exhibit similar inhibition profiles as their carbon side chain analogues, homoserine (65) and pentahomoserine (67). In contrast to this reasoning, asparagine- and glutamine containing compounds 68 and 73 proved to be considerably more potent Bli, B2i and B5c inhibitors than their homoserine (65) and pentahomoserine (67) counterparts. Identical to what was observed for the comparisons between Morph-Dap 59 versus Morph-Dab 62 and Morph-HSer 65 versus Morph-HHSer 67, increases in carbon side chain length caused decreases in potency for either Bli or B2i or both.

[0236] Previously analysed data showed that when comparing LU-005i 1 featuring an N- terminal 2-morpholinoacetyl cap with an identical compound featuring a / V-Boc piperazinyl cap, the latter proved to be the more potent compound toward all iCP activities. Compound 28 in contrast proved to be poor inhibitors for all of the cCP / iCP active sites, while BocPip-Ser(OBn) 35 inhibited all six cCP / iCP active sites, albeit with varying potencies. The one-carbon homologue (with respect to the P3 moiety) 69 and two-carbon homologue 71, showed a cCP / iCP potency and selectivity largely comparable with that of compound 34, having a serine at P3. Compound 36, not featuring a O-benzylated P3 residue, in contrast proved to be a more potent Bli and B2i inhibitor when compared to LU-005i 1. Interestingly, this compound also proved to a be three-fold more potent B2c inhibitor when compared to 35.

[0237] X-Ray structures of BocPip-Ser(OBn) 35 revealed that the / V-Boc piperazine cap displayed strong hydrophobic interactions with the residues in the S4 pocket of yB2 and yB5. This anchors the BocPip P4 residue in the S4 pocket in a way the smaller more hydrophilic morpholine cap cannot. The apparent ICso data found in Figure 5 corroborates this, and it can be concluded that B2i inhibitory potency within this class of compounds is independent of the nature of the P3 residue.

[0238] As well, perusal of the inhibitors featuring either a serine, a homoserine or a pentahomoserine at P3 revealed Morph-HSer 65 to be the strongest inhibitor of Bli and B2i and also showed the best ratio of weak cCP inhibition versus strong iCP inhibition. Additionally, the compounds featuring an amine residue at P3 are less potent Bli and B2i inhibitors compared to their OH analogues (65 and 67), as well as LU-005i 1.

[0239] Example 8 - Synthesis of compounds 74 - 76

[0240] Compounds 74 - 76 as shown below have been synthesized by methods analogous to those described in Examples 1, 3 and 6. Further synthetic details are provided below.

[0241] Example 1 described the synthesis of epoxyketone 83 and with large quantities of 83 in hand efforts were focused on the synthesis of P2-P3-P4 fragments featuring a homoserine at P3 (Scheme 7). For the synthesis of target peptide epoxyketones 74- 76, the carboxylic acid sidechain of aspartic acid 112 was activated using isobutylchloroformate, after which sodium borohydride was added thereby reducing the anhydride intermediate to homoserine derivative 114. The benzyl ester of 114 was then saponified using lithium hydroxide to form carboxylic acid 116. Next, addition of two equivalents of sodium hydride, followed by addition of one equivalent of benzyl bromide, O-Bn homoserine 118 was obtained. Consecutive condensation of 118 with 4-methoxy phenylalanine methyl ester afforded / V-Boc dipeptide 120. De- / V-Bocylation of 120 with TEA in DCM resulted in a free amine which was subsequently condensed with 2-morpholinoacetic acid to yield methyl ester 122. Methyl ester 122 was then converted into acyl hydrazide 140 which could then be transformed into the acyl azide intermediate using tert-butyl nitrite under anhydrous acidic conditions. After full conversion, as monitored by LC-MS, the reaction was neutralized with DiPEA, followed by addition of epoxyketone 83 forming target compound 74. In addition, removal of the O-benzyl protecting group in 74 was achieved through hydrogenation using Pd on carbon under a hydrogen saturated atmosphere affording OH HSer target compound 75. The OH group in 74 was then functionalized through Streglich esterification with / V-Boc alanine to form / V-Boc alanine ester compound 76. Subsequent deprotection of the O-Bn group of 76 proved successful with use of palladium on carbon under a hydrogen saturated atmosphere, with the unfortunate side reaction of hydrogenation of the epoxide yielding C-0 bond cleavage forming an alcohol moiety.

[0242] Scheme 7. Synthesis of P3 HSer LU-005i-OH analogues 74, 75 and N-Boc alanine ester derivative 76. Reagents and conditions: (a) i: isobutylchloroformate, NMM, THF, 0 °C, ii: NaBH4, MeOH, 0°C -> rt, 81%; (b) LiOH, H2O / MeOH 1 : 1, rt, quant.; (c) NaH, BnBr, DMF, 0 °C -> rt, 62%; (d) i: TEA, DCM, rt, ii: NH2-Tyr(OMe)-OMe, HCTU, DiPEA, DMF, rt; (e) i: TEA, DCM, rt, ii: 2-morpholinoacetic acid, HCTU, DiPEA, DMF, rt, 75%; (f) hydrazine hydrate, MeOH, rt; (g) i: tBuONO, HCI, DMF, -30 °C, ii: 83, DiPEA, DMF, -30 °C -> rt, 69%; (h) Pd / C, H2, MeOH, rt; (i) NHBoc-Ala-CO2H, DIC, DMAP, DCM, rt; (j) i: Pd / C, H2, MeOH, rt, ii: TEA, DCM, rt; (k) i: Pd / C, H2, MeOH, rt, ii: TEA, DCM, rt. Example 9 - Competitive ABPP assay in Raji cell lysate

[0243] The potency and selectivity profiles of the synthesized compounds 74-76, compared to compounds 2, 3, 14, 65 and 68 as proteasome inhibitors were determined using a competitive ABPP assay, in Raji cell lysates (B-cell lymphoma cell line that expresses both cCPs and iCPs). To further broaden the scope of all new proteasome inhibitors, AMO-wildtype cells were selected as an additional cell lysate to evaluate proteasome inhibitors in (AMO-wt, a plasmacytoma cell line that also expresses both cCPs and iCPs, Figure 6).

[0244] Compounds 74-76 as well as lead structures 2, 3, 14, 65 and 68 were tested in a concentration range from 0.003 pM to 10 pM to determine the apparent inhibitor concentration (ICso), both in Raji cell lysates and lysates from AMO-wt cells. The resulting apparent ICso values were plotted as a heat-maps shown in Figure 5 and 6. All compounds proved to be weak inhibitors for Bic and B2c in Raji cell lysates (Figure 5). As shown in Reference Example 7 peptide epoxyketones featuring an O-benzyl homoserine at the P3 position are potent inhibitors of the Bli, B5c and B5i active sites. Strikingly, compounds 74 and 76 proved to be as potent for Bli, B5c and B5i as Morph- HSer(OBn) 65, and also an increase in potency for B2i was observed for these compounds, when compared to LU-005i 1. Moreover, compound 76 showed a fourfold decrease in potency for Bli and a three-fold decrease in potency for B2i, compared to 74. In comparison with the compounds described in Reference Example 7, Morph- HSer 65 was the sole inhibitor that showed increased potencies for Bli, B2i and B5i in addition to a decrease in potency for B5c when compared to LU-005i 1. Compound 75, that features a homoserine at the P3 positions and a hydroxymethyl at the Pl' position, turned out to be a more selective iCP inhibitor in comparison to Morph-HSer 65. Specifically, an increase in potency of over ten-fold was observed for B2i and a decrease in potency for B5c of two-fold was observed when comparing compounds 75 and 65. When comparing 75 with LU-005i-OH 2, a four-fold increase in potency was observed for B2i, a two-fold decrease in potency for B5c, and most interesting, a fivefold decrease in potency for Bli.

[0245] The cCP / iCP active site (inhibitory potencies of compounds 2, 3, 14, 65 and 68 in AMO-wt lysates are depicted in, Figure 6. When comparing the IC50 values of 1-9 found for Raji lysates (Figure 5) with the ICso values of 2, 3, 14, 65 and 68 found for AMO- wildtype lysates (Figure 6), the overall inhibition profiles appeared mostly very similar. Interestingly, LU-005i-OH 2 proved to be a much more potent inhibitor for both cCP and iCP active subunits in AMO-wt. In addition, 2 was as iCP selective in AMO- wt lysates as in Raji lysates, with at least a two-fold increase in potency for iCP active subunits versus cCP active subunits. / V-Boc alanine ester 3 showed a two-fold decrease in potency for Bli, a ten-fold decrease in potency for B5i and a six-fold increase in potency for B2i, when comparing its IC50 values in AMO-wt lysates with those in Raji lysates. Surprisingly, alanine- / V / 72 14 proved to be a less potent inhibitor for Bli and B2i, while turning out to be a more potent inhibitor for Bic and B2c. In Raji lysates, 14 proved to be iCP selective with at least a six-fold difference in potency for iCP active sites versus cCP active sites. In AMO-wt lysates, compound 14 did not prove to be as selective for iCP active sites when compared to Raji lysates. Compound 75 on the other hand, proved to be even more selective for iCP active subunits when comparing its ICso values in Raji lysates with its values in AMO-wt lysates, showing an almost two-fold decrease in potency for B5c in AMO-wt lysates. In contrast, when comparing the inhibition profiles of 75 with 65 in AMO-wt lysates, compound 75 proved to be a much more potent inhibitor for Bli and B2i, in addition to being more selective for the iCP active sites.

[0246] The following abbreviations may be used herein. aq aqueous

[0247] Boc tert-butoxycarbonyl

[0248] DCM dichloromethane

[0249] DIC N,N'-Diisopropylcarbodiimide

[0250] DIPEA N,N-diisopropylethylamine DMAP 4-dimethylaminopyridine DMF dimethylformamide DMSO dimethylsulfoxide5 EtOAc ethyl acetate EtOH ethanol

[0251] HCTU O-(lH-6-Chlorobenzotriazole-l-yl)-l,l,3,3-tetramethyluronium hexafluorophosphate MeCN acetonitrile

[0252] MeOH methanol

[0253] NMR nuclear magnetic resonance rt room temperature

[0254] Rt retention time

[0255] TBS tert-butyldimethylsilyl

[0256] TEA trifluoroacetic acid

[0257] THE tetra hydrofuran

[0258] TLC thin layer chromatography

Claims

Claims1. A compound of formula (I),wherein one of Raand Rbrepresents H, and the other represents -[CH2]m-X;X represents -OC(O)-Y, -C(O)-Y, -OH or OY;Y represents -Ci-6 alkyl (optionally substituted by -Z1- / 2) or -CH(Ry)-(Z1-Z2)n;Ryrepresents methylbiphenyl or a side chain of a proteinogenic amino acid, optionally wherein the side chain is in a chemically protected form; each Z1is independently -NH-, -N(RZ)~ or -O-;Rz, if present, is bound to Ryto form a proline ring; each Z2is independently H, -C(O)-Ci-4 alkyl, -C(O)O-Ci-4 alkyl or -Si(Ci-4 alkyl)s; m is 0, 1 or 2; n is 1 or 2; p is 0 or 1;Rcrepresents H or -Ci-4 alkyl optionally substituted with one or more Q substituents;Q represents -0Rd, -NHReor -C(O)NHRf;Rd, Reand Rfrepresent H, -C1-4 alkyl (optionally substituted with phenyl or methylphenyl), -C(O)-Ci-4 alkyl, -C(O)O-Ci-4 alkyl, -C(O)-Ci-4 alkenyl, -C(O)O-Ci-4 alkenyl, -C( = N)-NHz, -C( = N)-NH-(protecting group), or pyrimidinyl;A represents a cyclic moiety selected from the group consisting of:Rhrepresents H, Ci-4 alkyl or -C(O)O-Ci-4 alkyl;R' represents H, Ci-4 alkyl, -N(Rj)(Rk) or -OH;Rjand Rkindependently represent H or Ci-4 alkyl; or a pharmaceutically acceptable salt or solvate thereof.

2. The compound according to Claim 1, wherein Rbrepresents hydrogen.

3. The compound according to Claim 1 or Claim 2, wherein X represents -OC(O)- Y, -C(O)-Y or -OY.

4. The compound according to any one of the preceding claims, wherein Y represents -C3-5 alkyl (optionally substituted by -Zx-Z2) or -CH(Ry)-(Z1-Z2)n.

5. The compound according to any one of the preceding claims, wherein Ryrepresents methylbiphenyl, a side chain of a proteinogenic amino acid or a chemically protected form of a side chain of a proteinogenic amino acid, wherein said chemical protection involves attachment of a moiety selected from the group consisting of a benzoyl group, a benzyl group, and a trityl group.

6. The compound according to any one of the preceding claims, wherein :(i) m is 0 or 1; and / or(ii) n is 1.

7. The compound according to any one of the preceding claims, wherein Q represents -NH2, -NH-C(O)-CH3, -NH(Alloc), -NH-C( = N)-NH2, -NH-C( = N)-NH- (protecting group), -C(O)-NH2, -OH, -O-benzyl, -O-xylyl, or -NH(pyrimidinyl).

8. The compound according to any one of Claim 1 to 6, wherein Rcrepresents the side chain of serine, a protected derivative of a side chain of serine, or methyl.

9. The compound according to any one of the preceding claims, wherein A represents a morpholinyl group.

10. The compound according to any one of the preceding claims, wherein the compound is selected from the group consisting of:

11. A pharmaceutical formulation comprising a compound as defined in any one of Claims 1 to 10 in combination with a pharmaceutically-acceptable excipient.

12. A compound as defined in any one of Claims 1 to 10, or a pharmaceutical formulation as defined in Claim 11, for use in medicine.

13. A compound as defined in any one of Claims 1 to 10, or a pharmaceutical formulation as defined in Claim 11, for use in the treatment or prevention of a disease or condition in which pan-immunoproteasome inhibition is desired or required.

14. The compound or pharmaceutical formulation for use according to Claim 13, wherein the disease or condition is a haematological malignancy, a solid tumour, an auto-immune disease or an inflammatory disease.

15. The compound or pharmaceutical formulation for use according to Claim 13 or Claim 14, wherein the disease or condition is selected from the group consisting of leukemia, lymphoma, myeloma (including multiple myeloma), myelodysplasticsyndrome, myeloproliferative syndrome, prostate cancer, breast cancer, lung cancer, colon cancer, pancreatic cancer, renal cancer, ovarian cancer, osteosarcoma, Alzheimer's disease, brain inflammations, colitis-associated cancers, angiogenesis, viral myocarditis, acute kidney injury, ischemic stroke, preterm birth, abdominal aortic aneurysm, atherosclerosis, cardiac remodeling, Graft versus host disease (GvHD), inflammatory bowel disease, arthritis, polymyositis, dermatomyositis, autoimmune hepatitis, and lupus nephritis.

16. A process for the preparation of a compound of formula (I) as defined in Claim 1, which process comprises the step of reacting a compound of formula (II),wherein A, p and Rcare as defined in Claim 1, with a compound of formula (III)wherein Y is as defined in Claim 1.

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