Sphingosine 1 phosphate receptor modulators

Abstract

Structural formula (I): Provided is a compound having the formula: TIFF2023519308000034.tif35137, or a pharmaceutically acceptable salt, homolog, hydrate, or solvate thereof, wherein R is as defined herein. Such compounds serve as modulators of the sphingosine-1-phosphate receptor and have utility in treating conditions where activation of this receptor is medically indicated.

Description

[Technical field]

[0001] Modulators of the sphingosine-1-phosphate receptor are provided for treating conditions in which activation of the receptor is medically indicated. [Background technology]

[0002] The S1P1 / EDG1 receptor is a G protein-coupled receptor (GPCR) and a member of the endothelial differentiation gene (EDG) receptor family. Endogenous ligands for the EDG receptor include lysophospholipids such as sphingosine-1-phosphate (S1P). As with all GPCRs, ligation of the receptor propagates second messenger signals via activation of G proteins (alpha, beta and gamma). The development of small molecule S1P1 agonists and antagonists has provided insight into several physiological roles of the S1P1 / S1P receptor signaling system. To this end, S1P receptors have been divided into five subtypes (i.e., S1P1, S1P2, S1P3, S1P4 and S1P5), which are expressed in a wide variety of tissues and display distinct cellular properties. Agonism of the S1P1 receptor inhibits lymphocyte trafficking and sequesters them in lymph nodes and other secondary lymphoid tissues, resulting in rapid and reversible lymphopenia, presumably due to receptor ligation on both lymphatic endothelial cells and on the lymphocytes themselves (Rosen et al., Immunol. Rev., 195:160-177, 2003). Summary of the Invention

[0003] Briefly, there are provided modulators of sphingosine-1-phosphate receptors for the treatment of conditions in which activation of the receptor is medically indicated. In one embodiment, a compound of structural formula (I): [ka] [In the formula, R is as follows] or a pharma- ceutically acceptable salt, homolog, hydrate or solvate thereof is provided. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0004] As used in the specification and the appended claims, the singular forms "a," "an," and "the" include the plural forms unless the context clearly dictates otherwise. Furthermore, the words "comprise," "include," and "have," as used herein, are open-ended terms and do not exclude the presence of additional elements or components.

[0005] The present invention relates to compounds that modulate S1P receptors, as well as related products and methods for making and using these compounds. S1P receptors are divided into five subtypes (i.e., S1P1, S1P2, S1P3, S1P4 and S1P5), which are expressed in a wide variety of tissues and exhibit different cellular specificities. The compounds disclosed herein modulate one or more of these subtypes. In one embodiment, the compound is an "S1P1" modulator, so as to modulate subtype 1 of the sphingosine-1-phosphate receptor. In another embodiment, the compound modulates subtype 1 and another subtype, such as subtype 5. As used herein, "S1P1 modulator" is understood to include compounds that modulate only the S1P1 subtype, or modulate the S1P1 subtype as well as one or more other subtypes. In one embodiment, the S1P1 modulator modulates both the S1P1 and S1P5 subtypes.

[0006] As used herein, a "modulator" of the S1P1 receptor is a compound that, when administered to a subject, provides the desired integration with the target receptor, either by the compound acting directly on the receptor itself or by a metabolite of the compound acting on the receptor. When administered to a subject, the compounds of the present invention modulate the S1P1 receptor by activating the receptor for signal transduction. Such compounds are also referred to herein as "agonists" or "S1P1 agonists." Such S1P1 agonists may be selective in their action on S1P1. For example, a compound selective in its action on S1P1 acts on S1P1 at a lower concentration than on other subtypes of the S1P receptor family.

[0007] Receptor agonists can be classified as either orthosteric or allosteric, and the S1P1 agonist of the present invention encompasses both classifications, either the compound acts on the receptor or the metabolite of the compound acts on the receptor.In certain embodiments, the compound of the present invention is an orthosteric agonist.Orthosteric agonists bind to the site on the receptor that overlaps significantly with the binding of natural ligands, and reproduce the key interaction between natural ligands and receptors.Orthosteric agonists will activate receptors by molecular mechanisms similar to those of natural ligands, and will compete with natural ligands and competitively antagonize pharmacological agents that are competitive antagonists for natural ligands.

[0008] In certain other embodiments, the compounds of the present invention are allosteric agonists. Allosteric agonists bind to the site of the receptor that does not overlap with the natural ligand, either partially or completely, but leads to some significant interaction. Allosteric agonists are true agonists, not allosteric enhancers. As a result, allosteric agonists only activate the signal transduction of the receptor, and do not require the submaximal concentration of the natural ligand. Allosteric agonists can be identified when antagonists known to compete with orthosteric ligands show non-competitive antagonism. Allosteric agonist sites can also be mapped by mutagenesis of the receptor.

[0009] In one embodiment, a compound of structural formula (I): [ka] [In formula: R is Alkyl; Alkanediyl-NR 1 R 2 ; Alkanediyl-C(=O)OR 1 ;or heterocyclylalkyl; R 1 and R 2 are independently H or C 1-4 is alkyl] or a pharma- ceutically acceptable salt, homolog, hydrate or solvate thereof is provided.

[0010] When used in formula (I), the following terms have the following meanings. "Alkanediyl" is derived from an alkyl group. 1 It means a divalent group, such as methylene (-CH2-), derived by removing two hydrogen atoms. Thus, any alkyl group as defined herein is 1 By removing one hydrogen atom to form a divalent group, an alkanediyl is formed.

[0011] "Alkyl" refers to the saturation of a straight-chain, branched-chain, or cyclic alkyl group (cycloalkyl). In harmony and having from 1 to about 20 carbon atoms (C 1-20 Alkyl means an alkyl group having from 1 to 12 carbon atoms (C alkyl), and in the case of cycloalkyl, from 3 to 20 carbon atoms. 1-12 alkyl), or in some embodiments, 1 to 8 carbon atoms (C 1-8 alkyl), or in some embodiments, 1 to 4 carbon atoms (C 1-4 alkyl), or in some embodiments, 1 to 3 carbon atoms (C 1-3 Examples of straight chain alkyl groups include, but are not limited to, methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, n-heptyl, and n-octyl groups. Examples of branched alkyl groups include, but are not limited to, isopropyl, isobutyl, sec-butyl, t-butyl, neopentyl, isopentyl, and 2,2-dimethylpropyl groups. 。 Examples of cycloalkyl include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups. In some embodiments, cycloalkyl groups have 3 to 8 ring members, while in other embodiments, the number of ring carbon atoms ranges from 3 to 5, 3 to 6, or 3 to 7. Cycloalkyl groups further include polycyclic cycloalkyl groups, such as, but not limited to, norbornyl, adamantyl, bornyl, camphenyl, isocamphenyl, and carenyl groups, and fused rings, such as, but not limited to, decalinyl, and the like.

[0012] "Alkenyl" refers to a straight chain, branched or cyclic alkyl group as defined above, where there is at least one double bond between two carbon atoms. Thus, an alkenyl group has from 2 to about 20 carbon atoms, typically from 2 to 12 carbon atoms, or in some embodiments, from 2 to 8 carbon atoms. Examples include, but are not limited to, CH=CH(CH3), CH=C(CH3)2, C(CH3)=CH2, C(CH3)=CH(CH3), C(CH2CH3)=CH2, vinyl, cyclohexenyl, cyclopentenyl, cyclohexadienyl, butadienyl, pentadienyl, and hexadienyl, and the like.

[0013] "Alkynyl" refers to a straight chain, branched or cyclic alkyl group as defined above, where there is at least one triple bond between two carbon atoms. Thus, an alkynyl group has from 2 to about 20 carbon atoms, typically from 2 to 12 carbon atoms, or, in some embodiments, from 2 to 8 carbon atoms. Examples include, but are not limited to, -C≡CH, -C≡C(CH3), -C≡C(CH2CH3), -CH2C≡CH, -CH2C≡C(CH3), and -CH2C≡C(CH2CH3).

[0014] "Heterocyclyl" refers to aromatic (heteroaryl) and non-aromatic ring compounds containing three or more ring members, one or more of which are heteroatoms. In some embodiments, heterocyclyl contains 3 to 20 ring members, while other such groups have 3 to 15 ring members. At least one ring contains a heteroatom, but not all rings in a polycyclic ring system need contain heteroatoms. For example, dioxolanyl and benzdioxolanyl ring systems (methylenedioxyphenyl ring systems) are both heterocyclyl groups as used herein. A heterocyclyl group referred to as C2-heterocyclyl can be a 5-membered ring with 2 carbon atoms and 3 heteroatoms, a 6-membered ring with 2 carbon atoms and 4 heteroatoms, etc. Similarly, a C4-heterocyclyl can be a 5-membered ring with 1 heteroatom, a 6-membered ring with 2 heteroatoms, etc. The sum of the number of carbon atoms and the number of heteroatoms totals to equal the total number of ring atoms. Saturated heterocyclic rings refer to heterocyclic rings that do not contain unsaturated carbon atoms. Heterocyclic rings include fused ring species, including fused ring species of aromatic and non-aromatic groups. They also include, but are not limited to, polycyclic ring systems containing heteroatoms, such as quinuclidyl.

[0015] Representative heterocyclyls include, but are not limited to, pyrrolidinyl, furanyl, tetrahydrofuranyl, dioxolanyl, piperidinyl, piperazinyl, morpholinyl, pyrrolyl, pyrazolyl, triazolyl, tetrazolyl, oxazolyl, isoxazolyl, thiazolyl, pyridinyl, thiophenyl, benzothiophenyl, benzofuranyl, dihydrobenzofuranyl, indolyl, dihydroindolyl, azaindolyl, indazolyl, benzimidazolyl, azabenzimidazolyl, benzoxazolyl, benzothiazolyl, benzothiadiazolyl, imidazopyridinyl, isoxazolopyridinyl, thianaphthalenyl, purinyl, xanthinyl, adeninyl, guaninyl, quinolinyl, isoquinolinyl, tetrahydroquinolinyl, quinoxalinyl, and quinazolinyl groups.

[0016] "Heterocyclylalkyl" means an alkyl group as defined above in which a hydrogen or carbon bond of the alkyl group is replaced with a bond to a heterocyclyl group as defined above. "Heteroaryl" refers to an aromatic heterocyclyl containing five or more ring members, one or more of which is a heteroatom. A heteroaryl group referred to as C2-heteroaryl can be a five-membered ring having two carbon atoms and three heteroatoms, a six-membered ring having two carbon atoms and four heteroatoms, etc. Similarly, a C4-heteroaryl can be a five-membered ring having one heteroatom, a six-membered ring having two heteroatoms, etc. The number of carbon atoms plus the number of heteroatoms totals up to the total number of ring atoms.

[0017] Representative heteroaryls include, but are not limited to, pyrrolyl, pyrazolyl, triazolyl, tetrazolyl, oxazolyl, isoxazolyl, thiazolyl, pyridinyl, thiophenyl, benzothiophenyl, benzofuranyl, indolyl, azaindolyl, indazolyl, benzimidazolyl, azabenzimidazolyl, benzoxazolyl, benzothiazolyl, benzothiadiazolyl, imidazopyridinyl, isoxazolopyridinyl, thianaphthalenyl, purinyl, xanthinyl, adeninyl, guaninyl, quinolinyl, isoquinolinyl, tetrahydroquinolinyl, tetrahydroisoquinolinyl, quinoxalinyl, and quinazolinyl groups.Heteroaryls also include fused ring compounds where at least one ring, but not necessarily all rings, is aromatic, including, for example, tetrahydroquinolinyl, tetrahydroisoquinolinyl, indolyl, and 2,3-dihydroindolyl. "Heteroarylalkyl" means an alkyl group as defined above in which a hydrogen or carbon bond of the alkyl group is replaced with a bond to a heteroaryl group as defined above.

[0018] In one embodiment, there is provided a compound having the structure of Formula (I), or a pharma- ceutically acceptable salt, homolog, hydrate, or solvate thereof, where R is alkyl, and in a more particular embodiment, alkyl is methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or tert-butyl. In one embodiment, there is provided a compound having the structure of Formula (I), or a pharma- ceutically acceptable salt, homolog, hydrate, or solvate thereof, wherein R is alkanediyl-NR 1 R 2 and R 1 and R 2 are independently H or C 1-4 or a pharma- ceutically acceptable salt, homolog, hydrate or solvate thereof is provided.

[0019] In one embodiment, a compound having the structure of Formula (I), or a pharma- ceutically acceptable salt, homolog, hydrate, or solvate thereof, wherein R is alkanediyl-C(=O)OR 1 and R 1 is H or C 1-4 or a pharma- ceutically acceptable salt, homolog, hydrate or solvate thereof is provided. In one embodiment, the present invention provides a compound having the structure of Formula (I), or a pharma- ceutically acceptable salt, homolog, hydrate, or solvate thereof, wherein R is heterocyclylalkyl, and heterocyclylalkyl is -(CH2) 1-3 Provided is a compound which is a heterocycle, wherein the heterocycle is as defined above, or a pharma- ceutically acceptable salt, homolog, hydrate or solvate thereof.

[0020] Representative compounds of formula (I) are listed in Table 1. Table 1 [Table 1] [Table 2] [Table 3] [Table 4]

[0021] As noted above, the compounds of structural formula (I) also include pharma- ceutically acceptable salts, homologs, hydrates or solvates thereof.

[0022] As is well known in the art, a "salt" includes organic compounds in which, for example, a carboxylic acid, a sulfonic acid, or an amine is combined in ionic form with a counterion. For example, an acid in its anionic form can form a salt with a metal cation, such as sodium, potassium, etc., e.g., NH +Or ammonium salts with cations of various amines (including tetraalkylammonium salts such as tetramethylammonium, and alkylammonium salts such as tromethanamine salts), or other cations, such as trimethylsulfonium. A "pharmacologically acceptable" or "pharmacologically acceptable" salt is a salt formed from an ion that is approved for human consumption, such as a chloride salt or a sodium salt, and is generally non-toxic. A "zwitterion" is an internal salt that can be formed in a molecule that has at least two ionizable groups, one forming an anion and the other a cation, which serve to balance each other. For example, amino acids such as glycine can exist in the form of a zwitterion. A "zwitterion" is a salt within the scope of the contemplation herein. The compounds of the present disclosure may take the form of a salt. The term "salt" includes addition salts of free acids or free bases that are compounds of the present disclosure. The salt may be a "pharmacologically acceptable salt". The term "pharmacologically acceptable salt" refers to a salt that has a toxicity profile within the range that makes it useful in pharmaceutical applications. Salts that are not pharma- ceutically acceptable may nevertheless possess properties, such as high crystallinity, that make them useful in practicing the present disclosure, e.g., useful in processes for synthesizing, purifying, or formulating the compounds of the present disclosure.

[0023] Suitable pharma- ceutically acceptable acid addition salts may be prepared from an inorganic acid or from an organic acid. Examples of inorganic acids include hydrochloric, hydrobromic, hydroiodic, nitric, carbonic, sulfuric, and phosphoric acid. Suitable organic acids may be selected from the aliphatic, alicyclic, aromatic, araliphatic, heterocyclic, carboxylic or sulfonic classes of organic acids, examples of which include formic acid, acetic acid, propionic acid, succinic acid, glycolic acid, gluconic acid, lactic acid, malic acid, tartaric acid, citric acid, ascorbic acid, glucuronic acid, maleic acid, fumaric acid, pyruvic acid, aspartic acid, glutamic acid, benzoic acid, anthranilic acid, 4-hydroxybenzoic acid, phenylacetic acid, mandelic acid, embonic acid (pamoic acid), methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, pantothenic acid, trifluoromethanesulfonic acid, 2-hydroxyethanesulfonic acid, p-toluenesulfonic acid, sulfanilic acid, cyclohexylaminosulfonic acid, stearic acid, alginic acid, β-hydroxybutyric acid, salicylic acid, galactaric acid, and galacturonic acid. Examples of pharma- ceutically unacceptable acid addition salts include, for example, perchlorates and tetrafluoroborates.

[0024] Suitable pharmaceutically acceptable base addition salts of the compounds of the present disclosure include, for example, metal salts, including alkali metal, alkaline earth metal and transition metal salts, such as, for example, calcium, magnesium, potassium, sodium and zinc salts. Pharmaceutically acceptable base addition salts also include, for example, organic salts prepared from basic amines, such as N,N'-dibenzylethylenediamine, chloroprocaine, choline, diethanolamine, ethylenediamine, meglumine (N-methylglucamine) and procaine. Examples of pharmaceutically unacceptable base addition salts include lithium salts and cyanate salts. Although pharmaceutically unacceptable salts are generally not useful as pharmaceuticals, such salts may be useful, for example, as intermediates in synthesizing compounds and in purifying them, for example, by recrystallization. All of these salts can be prepared by conventional means from the corresponding compounds, for example, by reacting the appropriate acid or base with the compound. The term "pharmaceutically acceptable salts" refers to non-toxic inorganic or organic acid and / or base addition salts. See, e.g., Gould et al., Salt Selection for Basic Drugs (1986), Int J. Pharm., 33, 201-217, incorporated herein by reference.

[0025] Non-limiting examples of possible salts of the present disclosure include hydrochloride, citrate, glycolate, fumarate, malate, tartrate, mesylate, ethanesulfonate, cinnamate, isethionate, sulfate, phosphate, diphosphate, nitrate, hydrobromide, hydroiodide, succinate, formate, acetate, dichloroacetate, lactate, p-toluenesulfonate, palmitate, pidorate, pamoate, salicylate, 4-aminosalicylate, benzoate, 4-acetamidobenzoate, glutamate, aspartate, glycolate, adipate, alginate. , ascorbate, besylate, camphorate, camphorsulfonate, camsylate, caprate, caproate, cyclamate, lauryl sulfate, edisylate, gentisate, galactarate, gluceptate, gluconate, glucuronate, oxoglutarate, hippurate, lactobionate, malonate, maleate, mandelate, napsylate, napadisylate, oxalate, oleate, sebacate, stearate, succinate, thiocyanate, undecylenate, and xinafoate.

[0026] A "homolog" of a compound of the present disclosure is a compound in which one or more atoms of the compound are replaced by an isotope of such atom. For example, a homolog includes a compound in which deuterium is substituted for one or more hydrogen atoms of the compound, such as the compound of the present disclosure, in which the methyl group of the isopropoxy portion of formulas IR and IS is fully or partially deuterated (e.g., (D3C)2CHO-). Isotopic substitutions that can be made to form a homolog of the present disclosure include non-radioactive (stable) atoms such as deuterium and carbon-13, and radioactive (unstable) atoms such as tritium, carbon-14, iodine-123, iodine-125, etc.

[0027] A "hydrate" is a compound that exists with water molecules in a composition. The composition may contain stoichiometric amounts of water, such as monohydrate or dihydrate, or may contain random amounts of water. As the term is used herein, "hydrate" refers to a solid form, i.e., a compound in an aqueous solution may be hydrated, but is not a hydrate as the term is used herein.

[0028] A "solvate" is a similar composition, except that water is replaced with a solvent other than water. For example, methanol or ethanol can form an "alcoholate", which again can be stoichiometric or non-stoichiometric. As the term is used herein, a "solvate" refers to a solid form, i.e., a solution of a compound in a solvent, although it may be solvated, is not a solvate as the term is used herein. The compounds disclosed herein can be prepared by techniques known to those of ordinary skill in the art, as well as by the procedures disclosed in the Examples below.

[0029] Working Example General Method of Synthesis 1 H NMR (400MHz) and 13 C NMR (100 MHz) was obtained in deuterated chloroform (CDCl3), deuterated methanol (CD3OD) or dimethylsulfoxide-D6 (DMSO) solutions. NMR spectra were processed using Mestrec 5.3.0 and 6.0.1. 13C NMR peaks in brackets are the two rotamers of the same carbon. Mass spectrometry (LCMS) was obtained using an Agilent 1100 / 6110 HPLC system equipped with a Thompson ODS-A, 100A, 5μ (50x4.6mm) column, using water + 0.1% formic acid as mobile phase A and acetonitrile + 0.1% formic acid as mobile phase B. The gradient was 20-100% with mobile phase B over 2.5 min, then held at 100% for 2.5 min. The flow rate was 1 mL / min. For more hydrophobic compounds, the following gradient was used, referred to as method 1 (40-95% over 0.5 min, held at 95% for 8.5 min, then returned to 40% over 2 min, flow rate 1 mL / min). The final compound was checked for purity using method 2 (5% for 1 min, 5-95% over 9 min, then hold at 95% for 5 min, flow rate 1 mL / min). Enantiomeric excess was measured by integrating the separated peaks on a Chiralpak AD-H, 250x4.6mm column, 5μm particle size. The flow rate was 1 mL / min, and the mobile phase was isocratic. Unless otherwise stated, chiral data provided uses this method. Alternatively, chiral separations were performed under the following conditions, referred to as Chiral Method 1, Chiral Method 2: Chiral Method 1 (Chiralpak AY-H, 250x4.6mm column, 5μ particle size; flow rate: 1 mL / min, and mobile phase: isocratic), and Chiral Method 2 (Chiralcel OZ-3, 250x4.6, 3μm particle size, flow rate: 0.75 ml / min). Pyridine, dichloromethane (DCM), tetrahydrofuran (THF) and toluene used in the runs were from Aldrich Sure-Seal bottles stored under nitrogen (N2). All reactions were magnetically stirred and at external reaction temperature. Chromatographic runs were performed using a Combiflash Rf flash purification system (Teledyne Isco) equipped with a Redisep (Teledyne Isco) silica gel (SiO2) column.Preparative HPLC purification was performed on a Varian ProStar / PrepStar system using water containing 0.05% trifluoroacetic acid as mobile phase A and acetonitrile containing 0.05% trifluoroacetic acid as mobile phase B. The gradient was 10-80% with mobile phase B over 12 min, then held at 80% for 2 min, then back to 10% over 2 min, at a flow rate of 22 mL / min. Other methods similar to this procedure may also be utilized. Fractions were collected using a Varian Prostar fraction collector and evaporated using a Savant SpeedVac Plus vacuum pump. Microwave heating was performed using a Biotage Initiator microwave reactor equipped with a Biotage microwave vessel. The following abbreviations were used: ethanol (EtOH), carbonyldiimidazole (CDI), isopropanol (IPA) and 4-dimethylaminopyridine (DMAP).

[0030] Example 1 Synthesis of compound number 1 [ka]

[0031] Step 1: Synthesis of 3-ethoxy-1H-indene-7-carbonitrile (Intermediate 2): A stirred mixture of 1-oxo-2,3-dihydro-1H-indene-4-carbonitrile (Intermediate 1) (20.0 g, 98 wt%, 18.6 g assay, 124.8 mmol) in anhydrous EtOH (20 mL), triethyl orthoformate (80 mL, 481 mmol) and methanesulfonic acid (0.88 mL, 12.5 mmol) in toluene (80 mL) was heated at 43-47° C. After 1 hour, GC analysis showed that the orthoformate had been consumed, leaving 12.8 area % of Intermediate 1. An additional charge of triethyl orthoformate (20 mL, 120.2 mmol) was made and after 45 minutes GC analysis showed the presence of 1.5 area % of Intermediate 1. The batch was cooled to ambient temperature and then vigorously stirred and poured into 1M aqueous K2HPO4 (200 mL) while maintaining a quench temperature of <15°C. The biphasic mixture was vigorously stirred for 10 minutes. The phases were separated and the aqueous phase (pH 11) was back extracted with toluene (100 mL). The organic phases were combined and distilled at atmospheric pressure, removing 340 mL of distillate. Toluene (500 mL) was added and distilled at atmospheric pressure, removing 500 mL of distillate. The distillation time was 3 hours total, with a temperature range of 80-120°C. At this point the batch was stored at <5°C overnight. Excess orthoformate was removed by chasing under reduced pressure with ethyl acetate (100 mL) until distillation ceased. Another volume of ethyl acetate (100 mL) was added and then concentrated under reduced pressure until distillation ceased. A third volume of ethyl acetate (100 mL) was added and then concentrated under reduced pressure until distillation ceased after which GC analysis confirmed that no orthoformate remained. The crude material was then stirred at 110° C. for 1 hour to convert the intermediate ketal to 3-ethoxy-1H-indene-7-carbonitrile (Intermediate 2). After cooling, the crude material (a flowing oil, 21.34 g) was purified by HPLC using mesitylene as the internal standard. 1 Assayed for intermediate 2 by H NMR. The oil was assayed to be 78.1 wt% product = 16.73 g assay, 90.0 mmol = 72.1% yield assay. The crude was then purified by filtration through a plug of silica gel eluting with 15% EtOAc / Hexanes. Pure fractions were combined and used in the next step.1 H NMR (400MHz, d6-DMSO) δ 7.78(d,J=8.4,1H), 7.63(m,1H), 7.49(m,1H), 5.60(m,1H), 1.38(t,J=6,8Hz,1H), 1.19(t,J=6.8Hz,1H);LRMS:C 12 H 12 NO + Calculated for [M+H]: 186.2; Found: 186.2

[0032] Step 2: Synthesis of intermediate 3: A solution of 3-ethoxy-1H-indene-7-carbonitrile (Intermediate 2) in EtOAc / hexanes (650 mL) was concentrated under reduced pressure to approximately 17 mL and isopropyl alcohol (IPA, 40 mL) was added. The solution was concentrated to approximately 17 mL and a second volume of IPA (34 mL) was added. To this stirred solution was added aqueous hydroxylamine (50%, 30 mL, 455 mmol). The batch was then warmed to 35-40° C. for 5 hours and then stirred at ambient temperature overnight. The batch was cooled to 0° C. and subjected to seeding (50 mg) and the seed bed was stirred for 30 minutes to generate. Water (250 mL) was then added dropwise over approximately 1.5 hours. The batch was stirred at 0-20° C. for 1 hour. The product was isolated by filtration, the cake washed with water (100 mL) and dried on the filter under vacuum and nitrogen atmosphere to give 3-ethoxy-N-hydroxy-1H-indene-7-carboximidamide (Intermediate 3) (20.8 g, 90% yield). 1 H NMR (400MHz, d6-DMSO) δ 9.61(s,1H), 7.43(m,1H), 7.32(m,2H), 5.77(s,1H), 5.41(s,1H), 4.08(q,J=6.8Hz,2H), 3.45(s,2H), 1.39(t,J=6.8Hz,3H);LRMS:C 12 H 15 N2O2 + Calculated for [M+H]: 219.2; Found: 219.1

[0033] Step 3: N-((3-cyano-4-isopropoxybenzoyl)oxy)-3-ethoxy-1H-indene-7-carboximidamide (Intermediate 4): A mixture of CDI (16.64 g, 102.6 mmol) and 3-cyano-4-isopropoxylbenzoic acid (21.06 g, 102.6 mmol) in DMF (83 mL) was stirred at 20° C. for 1 h. A solution of 3-ethoxy-N-hydroxy-1H-indene-7-carboximidamide (Intermediate 3) (20.8 g, 93.3 mmol) in DMF (40 mL) was added via addition funnel over approximately 5 min. After approximately 30 min, the batch became viscous and an additional volume of DMF (40 mL) was added to aid in stirring. At this point, an HPLC assay indicated the reaction was complete. The resulting slurry was diluted with water (1.5 L), cooled to 0° C., and isolated by filtration. The filter cake was washed with water (1.5 L) and the product was dried on the filter under a stream of nitrogen to give N-((3-cyano-4-isopropoxybenzoyl)oxy)-3-ethoxy-1H-indene-7-carboximidamide (Intermediate 4) as an off-white solid (34.8 g, 90% yield). 1 H NMR (400MHz, d6-DMSO) δ 8.70(s,1H), 8.33(d,J=6.8Hz,1H), 7.45(m,4H), 7.10(m,2H), 5.49(s,1H), 4.94(m,1H), 4.10(q,J=6.8Hz,2H), 3.55(s,2H), 1.38(m,9H);LRMS:C 23 H 24 N3O4 + Calculated for [M+H]: 406.4; Found: 406.2

[0034] Step 4: Synthesis of 5-(3-(3-ethoxy-1H-inden-7-yl)-1,2,4-oxadiazol-5-yl)-2-isopropoxybenzonitrile (Intermediate 5) N-((3-cyano-4-isopropoxybenzoyl)oxy)-3-ethoxy-1H-indene-7-carboximidamide (Intermediate 4) (34.8 g, 83.97 mmol) was suspended in toluene (590 mL) and heated to reflux in a Dean-Stark apparatus for 18 h. Approximately 2 mL was collected (theoretical 1.5 mL). The batch was cooled to ambient temperature, filtered through Celite, and concentrated in vacuo. The crude solid 5-(3-(3-ethoxy-1H-inden-7-yl)-1,2,4-oxadiazol-5-yl)-2-isopropoxybenzonitrile (Intermediate 5) (30 g, 90% yield) was carried directly to the next step. LRMS: C 23 H 22 N3O3 + Calculated [M+H]: 388.4; Found: 388.3

[0035] Step 5: Synthesis of 2-isopropoxy-5-(3-(1-oxo-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)benzonitrile (compound number 1): Intermediate 5 (30 g, 75.57 mmol) is suspended in IPA / H2O (4:1) (300 mL). Catalytic H2SO4 (0.1 mL, 0.19 mmol) is added and the mixture is heated to reflux for 12 h. The slurry is cooled to ambient temperature and stirred for 1 h. The product is isolated by filtration and washed with IPA / H2O (4:1) (100 mL). After drying on the filter under vacuum for 1 h, the wet cake is returned to the reactor and suspended in EtOAc (300 mL). The mixture is heated to reflux for 3 h, then cooled to ambient temperature and stirred for 1 h. The slurry is filtered, washed with EtOAc (100 mL) and dried on the filter under nitrogen to give 2-isopropoxy-5-(3-(1-oxo-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)benzonitrile (compound no. 1) (22 g, 80% yield) as an off-white solid. 1H NMR (400MHz, d6-DMSO) δ 8.55(d,J=2.0Hz,1H), 8.44(m,2H), 7.88(d,J=7.6Hz,1H), 7.69(t,J=7.6Hz,1H), 7.57(d,J=9.2Hz,1H), 4.99( h,J=12.4Hz,1H), 3.46(dd,J1=5.6, J2=11.2Hz,2H), 2.76(dd,J1=5.6, J2=11.2Hz,2H), 1.45(d,J=12.4Hz,6H); 13 C NMR (100MHz, d6-DMSO) δ 205.9, 173.4, 167.4, 162.6, 154.2, 138.1, 134.7, 134.2, 133.9, 128.2, 1 25.9, 124.5, 115.8, 115.3, 114.9, 102.5, 72.6, 35.9, 27.3, 21.5;LRMS:C 21 H 18 N3O3 + Calculated [M+H]: 360.1; Found: 360.2; CHN analysis: Found: %C: 70.25, %H: 4.69; %N: 11.71; Theoretical: %C: 70.18; %H: 4.77; %N: 11.69

[0036] Example 2 General synthesis of compounds of formula (I) [ka] Compounds of formula (I) can be synthesized starting from compound 1 (Example 1). Treatment with a cyclic acid anhydride in the presence of a catalyst such as DMAP gives compounds of formula (I). Additionally, the formation of compounds of formula (I) can be achieved by treating compound 1 with a strong base, followed by trapping with an acid chloride.

[0037] [ka] Compounds of formula (I) can also be synthesized starting from compound 1 (Example 1) by treatment with a strong base followed by trapping with 2-haloacetic anhydride and amination of the corresponding alpha haloester with a tertiary amine (where R f1 , R f2and R f3 is C 1-4 (meaning alkyl, such as alkyl).

[0038] Example 3 compound 10 ((Z)-5-(3-(1-(hydroxyimino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)-2-isopropoxybenzonitrile Synthesis of [ka] 2-Isopropoxy-5-(3-(1-oxo-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)benzonitrile (100 mg, 0.28 mmol) was completely dissolved in DCM (8 ml) and 95% EtOH (4 ml), NH2OH (43 mg, 0.61 mmol) and NaOAc (52 mg, 0.61 mmol) were added at room temperature. The reaction progress was monitored by HPLC. After the reaction was completed (overnight), the precipitate was collected and washed with DCM (5 ml x 2) to give the pure product: (Z)-5-(3-(1-(hydroxyimino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)-2-isopropoxybenzonitrile (60 mg, 0.16 mmol, 57%). 1 H NMR (400MHz, DMSO-D6) δppm 1.40(d,J=8Hz,6H), 2.90(m,2H), 3.39(m,2H), 4.99(m,1H), 7.56(m,2H), 7.80(d ,J=8Hz,1H),8.14(d,J=8Hz,1H),8.42(d,J=8Hz,1H),8.54(s,1H),11.1(s,1H);C 21 H 18 ESIMS measured value as N4O3: m / z 375.3 (M+1)

[0039] Example 4 compound 11 ((Z)-4-(((4-(5-(3-cyano-4-isopropoxyphenyl)-1,2,4-oxadiazol-3-yl)-2,3-dihydro-1H-inden-1-ylidene)amino)oxy)butanoic acid Synthesis of [ka] 2-Isopropoxy-5-(3-(1-oxo-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)benzonitrile (100 mg, 0.28 mmol) was completely dissolved in DCM (8 ml) and 70% EtOH (4 ml), 4-(aminooxy)butanoic acid hydrochloride (95 mg, 0.61 mmol) and NaOAc (68 mg, 0.61 mmol) were added at room temperature. The reaction progress was monitored by HPLC. The reaction was stirred at room temperature for 48 h and achieved 30% conversion. The solvent was removed and directly loaded onto an ISCO for purification. However, no separation was achieved; so purification again by RP ISCO [5-95% MeOH (containing 0.05% AcOH) / water] afforded the desired product: (Z)-4-(((4-(5-(3-cyano-4-isopropoxyphenyl)-1,2,4-oxadiazol-3-yl)-2,3-dihydro-1H-inden-1-ylidene)amino)oxy)butanoic acid (19 mg, 0.041 mmol, 15%). 1 H NMR (400MHz, DMSO-D6) δppm 1.47(d,J=8Hz,6H), 2.09(m,2H), 2.54(m,2H), 2.95(m,2H), 3.41(m,2H), 4.26(m,2H), 4.80(m,1H), 7.10 (d,J=8Hz,1H), 7.40(m,1H), 7.83(d,J=8Hz,1H), 8.12(d,J=8Hz,1H), 8.34(d,J=8Hz,1H), 8.40(s,1H);C 25 H 24 ESIMS measured value as N4O5: m / z 461.3 (M+1)

[0040] Example 5 compound 12 ((Z)-4-(5-(3-((12-azaneilidene)-13-methyl)-4-isopropoxyphenyl)-1,2,4-oxadiazol-3-yl)-2,3-dihydro-1H-inden-1-one O-(3-(dimethylamino)propyl)oxime) Synthesis of [ka] (Z)-4-(5-(3-((12-Azaneilidene)-13-methyl)-4-isopropoxyphenyl)-1,2,4-oxadiazol-3-yl)-2,3-dihydro-1H-inden-1-one O-(3-(dimethylamino)propyl)oxime was prepared in 25% yield by following the procedure described in Example 4 except using 3-(aminooxy)-N,N-dimethylpropan-1-amine instead of 4-(aminooxy)butanoic acid hydrochloride. 1 H NMR (400MHz, chloroform-d) δppm 1.48(d,J=8Hz,6H), 2.25(m,2H), 2.7(s,6H), 2.97(m,4H), 3.45(m,2H), 4.29(m,2H), 4.81(m,1H), 7.12(d, C 26 H 29 ESIMS measured value as N5O3: m / z 460.5 (M+1)

[0041] Example 6 compound 13 ((Z)-4-(5-(3-((12-azaneilidene)-13-methyl)-4-isopropoxyphenyl)-1,2,4-oxadiazol-3-yl)-2,3-dihydro-1H-inden-1-one O-propionyl oxime) Synthesis of [ka] (Z)-4-(5-(3-((12-azaneilidene)-13-methyl)-4-isopropoxyphenyl)-1,2,4-oxadiazol-3-yl)-2,3-dihydro-1H-inden-1-one O-propionyl oxime was prepared in 3% yield by following the procedure described in Example 4, except that O-propionylhydroxylamine hydrochloride was used instead of 4-(aminooxy)butanoic acid hydrochloride. 24 H 22 ESIMS measured value as N4O4: m / z 431.5 (M+1)

[0042] Example 7 compound 14 ((Z)-2-isopropoxy-5-(3-(1-((2-methoxyethoxy)imino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)benzonitrile) Synthesis of [ka] (Z)-2-Isopropoxy-5-(3-(1-((2-methoxyethoxy)imino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)benzonitrile was prepared in 7% yield by following the procedure described in Example 4 except using O-(2-methoxyethyl)hydroxylamine instead of 4-(aminooxy)butanoic acid hydrochloride. 1 H NMR (400MHz, chloroform-d) δppm 1.48(d,J=8Hz,6H), 3.0(m,2H), 3.01(s,3H), 3.05(m,2H), 3.72(m,2H), 4.37(m,2H), 4.81(m,1H), 7.12(d, C 24 H 24 ESIMS measured value as N4O4: m / z 433.2 (M+1)

[0043] Example 8 compound 6 ((Z)-2-(((4-(5-(3-cyano-4-isopropoxyphenyl)-1,2,4-oxadiazol-3-yl)-2,3-dihydro-1H-inden-1-ylidene)amino)oxy)acetic acid Synthesis of [ka] (Z)-2-(((4-(5-(3-cyano-4-isopropoxyphenyl)-1,2,4-oxadiazol-3-yl)-2,3-dihydro-1H-inden-1-ylidene)amino)oxy)acetic acid was prepared in 42% yield by following the procedure described in Example 4 except using 2-(aminooxy)acetic acid hydrochloride instead of 4-(aminooxy)butanoic acid hydrochloride. 1 H NMR (400MHz, DMSO-D6) δppm 1.47(d,J=8Hz,6H), 2.92(m,2H), 3.29(m,2H), 4.62(s,2H), 4.80(m,1H), 7.48(m ,2H), 7.71(d,J=8Hz,1H), 8.11(d,J=8Hz,1H), 8.31(d,J=8Hz,1H), 8.40(s,1H);C 23 H 20 ESIMS measured value as N4O5: m / z 433.1 (M+1)

[0044] Example 9 compound 15 ((Z)-5-(3-(1-((2-(diethylamino)ethoxy)imino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)-2-isopropoxybenzonitrile) Synthesis of [ka] To 2-chloro-N,N-diethylethan-1-amine hydrochloride (138 mg, 0.8 mmol) in DMF (1.5 ml) was added Et3N (0.112 ml, 0.8 mmol) and stirred for 10 min at room temperature. Meanwhile, to (Z)-5-(3-(1-(hydroxyimino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)-2-isopropoxybenzonitrile (100 mg, 0.27 mmol) in DMF (1.5 ml) was added NaH (32 mg, 0.8 mmol, 60% in oil) at room temperature and stirred for 10 min. The first solution was then added to the second solution at room temperature and stirred overnight. The reaction mixture was poured into ice water and extracted with DCM (20 ml), and the DCM layer was washed with brine, dried, concentrated and purified by ISCO (eluting with 0-10% MeOH / DCM, 0.35 M NH3) to give the desired product: (Z)-5-(3-(1-((2-(diethylamino)ethoxy)imino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)-2-isopropoxybenzonitrile (23 mg, 0.048 mmol, 18%). 1 H NMR (400MHz, chloroform-d) δppm 1.07(m,6H), 1.47(d,J=8Hz,6H), 2.66(m,4H), 2.99(m,4H), 3.42(m,2H), 4.31(m,2H), 4.81(m,1H), 7.12(d, C 27 H 31 ESIMS measured value as N5O3: m / z 474.3 (M+H)

[0045] Example 10 compound 9 ((Z)-2-isopropoxy-5-(3-(1-((2-(piperidin-1-yl)ethoxy)imino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)benzonitrile) Synthesis of [ka] (Z)-2-Isopropoxy-5-(3-(1-((2-(piperidin-1-yl)ethoxy)imino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)benzonitrile was prepared in 37% yield by following the procedure described in Example 9 except using 1-(2-chloroethyl)piperidine hydrochloride instead of 2-chloro-N,N-diethylethan-1-amine hydrochloride. 1 H NMR (400MHz, chloroform-d) δppm 1.25(m,2H), 1.47(d,J=8Hz,6H), 1.77(m,4H), 2.76(m,4H), 2.99(m,4H), 3.42(m,2H), 4.31(m,2H), 4.81(m,1H), 7 .12(d,J=8Hz,1H),7.45(t,J=4Hz,1H),7.80(d,J=8Hz,1H),8.23(d,J=8Hz,1H),8.35(d,J=8Hz,1H),8.43(s,1H);C 28 H 31 ESIMS measured value as N5O3: m / z 486.5 (M+1)

[0046] Example 11 compound 7 ((E)-3-(((4-(5-(3-cyano-4-isopropoxyphenyl)-1,2,4-oxadiazol-3-yl)-2,3-dihydro-1H-inden-1-ylidene)amino)oxy)propionic acid Synthesis of [ka] (E)-3-(((4-(5-(3-cyano-4-isopropoxyphenyl)-1,2,4-oxadiazol-3-yl)-2,3-dihydro-1H-inden-1-ylidene)amino)oxy)propionic acid was prepared in 3% yield by following the procedure described in Example 4 except using 3-(aminooxy)propionic acid hydrochloride instead of 4-(aminooxy)butanoic acid hydrochloride. 1H NMR (400MHz, chloroform-d) δppm 1.47(d,J=8Hz,6H), 2.86(m,2H), 2.97(m,2H), 3.46(m,2H), 4.48(m,2H), 4.81(m,1H), 7.12(d,J=8Hz ,1H), 7.45(t,J=4Hz,1H), 7.80(d,J=8Hz,1H), 8.23(d,J=8Hz,1H), 8.35(d,J=8Hz,1H), 8.43(s,1H) 24 H 22 ESIMS measured value as N4O5: m / z 447.4 (M+1)

[0047] Example 12 compound 2 ((Z)-2-isopropoxy-5-(3-(1-(methoxyimino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)benzonitrile Synthesis of [ka] (Z)-2-Isopropoxy-5-(3-(1-(methoxyimino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)benzonitrile (N39-031) was prepared in 34% yield by following the procedure described in Example 4, except using O-methylhydroxylamine hydrochloride instead of 4-(aminooxy)butanoic acid hydrochloride. 1 H NMR (400MHz, chloroform-d) δppm 1.47(d,J=8Hz,6H), 2.97(m,2H), 3.44(m,2H), 4.01(s,3H), 4.81(m,1H), 7.12(d,J=8Hz,1H), 7 .45(t,J=4Hz,1H), 7.80(d,J=8Hz,1H), 8.23(d,J=8Hz,1H), 8.35(d,J=8Hz,1H), 8.43(s,1H);C 22 H 20 As N4O3, ESIMS measured value: m / z 389.1 (M+1)

[0048] Example 13 compound 2 ((Z)-5-(3-(1-(ethoxyimino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)-2-isopropoxybenzonitrile Synthesis of [ka] (Z)-5-(3-(1-(ethoxyimino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)-2-isopropoxybenzonitrile (N39-030) was prepared in 65% yield by following the procedure described in Example 4, except using O-ethylhydroxylamine hydrochloride instead of 4-(aminooxy)butanoic acid hydrochloride. 1 H NMR (400MHz, chloroform-d) δppm 1.34(m,3H), 1.47(d,J=8Hz,6H), 2.97(m,2H), 3.00(m,2H), 4.23(m,2H), 4.81(m,1H), 7.12(d,J=8Hz ,1H), 7.45(t,J=4Hz,1H), 7.80(d,J=8Hz,1H), 8.23(d,J=8Hz,1H), 8.35(d,J=8Hz,1H), 8.43(s,1H) 23 H 22 As N4O3, ESIMS measured value: m / z 402.4 (M+)

[0049] Example 14 compound 4 ((Z)-2-Isopropoxy-5-(3-(1-(isopropoxyimino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)benzonitrile) Synthesis of [ka] (Z)-2-Isopropoxy-5-(3-(1-(isopropoxyimino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)benzonitrile was prepared in 48% yield by following the procedure described in Example 4, except that O-isopropylhydroxylamine hydrochloride was used instead of 4-(aminooxy)butanoic acid hydrochloride. 24 H 24 ESIMS measured value as N4O3: m / z 417.2 (M+1)

[0050] Example 15 compound 5 ((Z)-5-(3-(1-(tert-butoxyimino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)-2-isopropoxybenzonitrile Synthesis of [ka] (Z)-5-(3-(1-(tert-butoxyimino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)-2-isopropoxybenzonitrile was prepared in 51% yield by following the procedure described in Example 4, except using O-(tert-butyl)hydroxylamine hydrochloride instead of 4-(aminooxy)butanoic acid hydrochloride. 1 H NMR (400MHz, chloroform-d) δppm 1.36(s,9H), 1.47(d,J=8Hz,6H), 2.97(m,2H), 3.44(m,2H), 4.81(m,1H), 7.12(d,J=8Hz,1H), 7 .45(t,J=4Hz,1H), 7.80(d,J=8Hz,1H), 8.23(d,J=8Hz,1H), 8.35(d,J=8Hz,1H), 8.43(s,1H);C 25 H 26 As N4O3, ESIMS measured value: m / z 431.2 (M+1)

[0051] Example 16 compound 16 ((Z)-5-(3-(1-((2-hydroxyethoxy)imino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)-2-isopropoxybenzonitrile Synthesis of [ka]

[0052] Step 1: To a solution of (E)-5-(3-(1-(hydroxyimino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)-2-isopropoxybenzonitrile (0.6 g, 1.6 mmol) in DMF (9 ml) was added NaH (192 mg, 4.8 mmol) and stirred for 20 min. To this DMF slurry was added a solution of 1,2-dibromoethane (3 g, 16 mmol) in DCM (6 ml). The reaction mixture was stirred at room temperature for 16 h. LCMS showed some conversion, the reaction mixture was diluted with DCM (100 mL) and washed with water (100 mL x 2). The organic layer was dried over Na2SO4, concentrated, and purified by ISCO (25 g column, 0-100% EtOAc / Hex) to give the desired product: (E)-5-(3-(1-((2-bromoethoxy)imino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)-2-isopropoxybenzonitrile (0.08 g, 0.166 mmol, 10%). 23 H 21 BrN4O3, ESIMS measured value: m / z 481.3 (M+1)

[0053] Step 2: To a 50 mL flask was added 2-methoxy-N-methylethan-1-amine (11 mg, 0.125 mmol), DMF (1 ml), NaH (5 mg, 0.125 mmol), then stirred for 5 min. To the stirred mixture was added a solution of (E)-5-(3-(1-((2-bromoethoxy)imino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)-2-isopropoxybenzonitrile (40 mg, 0.08 mmol) in DCM (4 ml), then stirred at room temperature for 16 h. The solvent was removed and the residue was purified by ISCO (4 g column, 0-10% MeOH / DCM, 0.35N NH3) to give the desired product: (E)-2-isopropoxy-5-(3-(1-((2-((2-methoxyethyl)(methyl)amino)ethoxy)imino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)benzonitrile (10 mg, 0.02 mmol, 24%). 1 H NMR (400MHz, chloroform-d) δppm 1.47(d,J=8Hz,6H), 2.49(s,3H), 2.50(m,2H), 2.80(m,2H), 2.99(m,2H), 3.40(s,3H), 3.46(m,2H), 3.50(m,2H), 4.36(m,2H), 4 C 27 H 31 ESIMS measured value as N5O4: m / z 490.5 (M+1)

[0054] Example 17 compound 17 ((E)-5-(3-(1-((2-(azetidin-1-yl)ethoxy)imino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)-2-isopropoxybenzonitrile) Synthesis of [ka] (E)-5-(3-(1-((2-(azetidin-1-yl)ethoxy)imino)-2,3-dihydro-1H-inden-4-yl)-1,2,4-oxadiazol-5-yl)-2-isopropoxybenzonitrile was prepared in 12.9% yield by following the procedure described in Example 16, Step 2, except using azetidine instead of 2-methoxy-N-methylethan-1-amine. 1 H NMR (400MHz, chloroform-d) δppm 1.47(d,J=8Hz,6H), 1.82(m,2H), 2.46(m,2H), 2.90(m,2H), 3.01(m,2H), 3.46(m,2H), 3.60(m,2H), 4.36(m,2H), 4.80(m, C 26 H 27 ESIMS measured value for N5O3: m / z 458.6 (M+1)

[0055] Example 18 compound 18 ((Z)-2-(((4-(5-(3-cyano-4-isopropoxyphenyl)-1,2,4-oxadiazol-3-yl)-2,3-dihydro-1H-inden-1-ylidene)amino)oxy)acetamide Synthesis of [ka] (Z)-2-(((4-(5-(3-cyano-4-isopropoxyphenyl)-1,2,4-oxadiazol-3-yl)-2,3-dihydro-1H-inden-1-ylidene)amino)oxy)acetamide was prepared in 19.4% yield by following the procedure described in Example 9 except using 2-chloroacetamide instead of 2-chloro-N,N-diethylethan-1-amine hydrochloride. 1H NMR (400MHz, chloroform-d) δppm 1.47(d,J=8Hz,6H), 3.00(m,2H), 3.5(m,2H), 4.69(s,2H), 4.78(m,1H), 5.50(s,1H), 6.40(s,1H), 7.12(d, C 23 H 21 ESIMS measured value as N5O4: m / z 432.4 (M+1)

[0056] Example 19 compound 19 ((E)-2-(((4-(5-(3-cyano-4-isopropoxyphenyl)-1,2,4-oxadiazol-3-yl)-2,3-dihydro-1H-inden-1-ylidene)amino)oxy)propionic acid Synthesis of [ka]

[0057] Step 1: Methyl (E)-2-(((4-(5-(3-cyano-4-isopropoxyphenyl)-1,2,4-oxadiazol-3-yl)-2,3-dihydro-1H-inden-1-ylidene)amino)oxy)propanoate was prepared in 80% yield by following the procedure described in Example 9, except using methyl 2-bromopropanoate instead of 2-chloro-N,N-diethylethan-1-amine hydrochloride. 25 H 24 ESIMS measured value as N4O5: m / z 461.4 (M+1)

[0058] Step 2: A stirred solution of (E)-methyl 2-(((4-(5-(3-cyano-4-isopropoxyphenyl)-1,2,4-oxadiazol-3-yl)-2,3-dihydro-1H-inden-1-ylidene)amino)oxy)propanoate (33 mg, 0.072 mmol) in THF (5 mL) and MeOH (2 mL) was treated with an aqueous solution of LiOH (10.3 mg, 0.215 mmol) (1 mL). The mixture was stirred at room temperature for 2 h. The mixture was then acidified to pH 1 with 6M HCl. The mixture was diluted with DCM (20 mL) and extracted with water (20 mL). The aqueous layer was extracted with DCM (20 mL x 3). The organic layers were combined, dried over Na2SO4, and then concentrated to give the desired product: (E)-2-(((4-(5-(3-cyano-4-isopropoxyphenyl)-1,2,4-oxadiazol-3-yl)-2,3-dihydro-1H-inden-1-ylidene)-amino)oxy)propionic acid (26 mg, 0.058 mmol, 81%). 1 H NMR (400MHz, chloroform-d) δppm 1.47(d,J=8Hz,6H), 1.43(s,1H), 1.63(d,J=8Hz,3H), 3.07(m,2H), 3.50(m,2H), 4.80(m,1H), 4.82(m,1H), 7.12 (d,J=8Hz,1H), 7.45(t,J=4Hz,1H), 7.80(d,J=8Hz,1H), 8.23(d,J=8Hz,1H), 8.35(d,J=8Hz,1H), 8.43(s,1H);C 24 H 22 ESIMS measured value as N4O5: m / z 447.4 (M+1)

[0059] Example 20 In vitro biological assays Cell membrane preparation CHO cells expressing recombinant S1P receptors were cultured at 500 cm 2The cells were cultured on a 100-well culture tray and, when confluent, rinsed and detached with cell lifting buffer (10 mM HEPES, 154 mM NaCl, 6.85 mM EDTA, pH 7.4). The cells were then pelleted by centrifugation, resuspended in membrane preparation buffer (10 mM HEPES and 10 mM EDTA, pH 7.4), and homogenized using a Polytron PT 1200E homogenizer (Kinematica, Luzern, Switzerland). Cell proteins were pelleted by centrifugation at 48,000×g for 30 min at 4° C. The resulting supernatant was discarded, and the pellet was resuspended again in membrane preparation buffer, homogenized once more, and then centrifuged again, as described above. The final cell protein pellet was suspended in ice-cold resuspension buffer (10 mM HEPES and 0.1 mM EDTA, pH 7.4), aliquoted, and stored at −80° C. until use.

[0060] GTPγS binding assay [ 35Binding assays for [S]-GTPγS were performed in 96-well non-binding surface plates in a final volume of 200 μL. Test compounds were serially diluted in DMSO and added to the assay plate in a total volume of 0.4 μL using a Tecan D300E digital dispenser. The control sphingosine-1-phosphate (S1P) was prepared separately by preparing a 400 μM stock solution in 10 mM Na2CO3 containing 2% β-cyclodextrin from 100 nmoles of S1P pellet. Serial dilutions of S1P were made in complete assay buffer (20 mM HEPES, 10 mM MgCl2, 100 mM NaCl, 1 mM EDTA, 0.1% fatty acid-free bovine serum albumin [BSA], and 30 μg / mL saponin, pH 7.4) and transferred to wells previously containing 0.4 μL DMSO. All wells were then loaded with a total volume of 40 μL complete assay buffer, except for the non-specific binding (NSB) wells. For the NSB wells, 40 μL / well of 50 μM GTPγS (Sigma Aldrich, Catalog No. G8634, St. Louis, MO) was added to wells containing 0.4 μL DMSO. The assay was initiated by adding 120 μL / well of CHO-S1P receptor membrane solution containing 40 μg / mL membrane protein, 16.67 μM guanosine diphosphate (GDP; Sigma Aldrich, Catalog No. G7127, St. Louis, MO), and 2.5 mg / mL WGA PVT SPA beads in complete buffer. The assay plate was then sealed and incubated for 30 minutes at room temperature with gentle agitation. Next, 1 nM of [ 35S]-GTPγS (PerkinElmer, Cat. No. NEG030X250UC, Waltham, MA) was added to the assay plate at 40 μL / well to give a final concentration of 200 pM, and the plate was further incubated for 40 minutes at room temperature with gentle agitation. The assay was terminated by centrifuging the plate at 1000 rpm for 3 minutes in an Eppendorf 5810R centrifuge (Eppendorf, Hamburg, Germany), and G protein-bound radioactivity was quantified using a MicroBeta2 microplate scintillation counter (PerkinElmer, Waltham, MA).

[0061] Data for representative compounds assayed by the above techniques are shown in Table 2. Table 2 [Table 5]

[0062] Example 21 In vivo biological assays Determination of absolute oral bioavailability in rats Pharmacokinetic studies are performed in nonfasted male Sprague-Dawley rats (Simonsen Laboratories or Harlan Laboratories). Rats are housed in an ALAAC-accredited facility and the studies are approved by the institutional Institutional Animal Care and Use Committee (IACUC). Animals are allowed to acclimate to the laboratory for at least 48 hours prior to initiating experiments.

[0063] Compounds are formulated in 5% DMSO / 5% Thuen 20 and 90% purified water (intravenous infusion) or 5% DMSO / 5% Thuen 20 and 90% 0.1N HCL (oral gavage). Concentrations of dosing solutions are verified by HPLC-UV. For intravenous dosing, compounds are administered via an infusion pump into the jugular vein over 1 min in manually restrained animals (n=4 rats per compound). Oral dosing is by gavage using a standard stainless steel gavage needle (n=2-4 rats per compound). For both routes of administration, blood is collected at 8 time points following dosing, with a final sample taken 24 hours after dosing. Aliquots of blood samples are transferred to polypropylene 96-well plates and frozen at -20°C until analysis.

[0064] After blood samples are thawed at room temperature, 5 μL of DMSO is added to each well. Proteins are precipitated by adding 150 μL of acetonitrile containing 200 nM of the internal standard (4-hydroxy-3-(alpha-iminobenzyl)-1-methyl-6-phenylpyrindin-2-(1H)-one) and 0.1% formic acid. The plate is mixed on a plate shaker for 1 minute to facilitate protein precipitation, and then centrifuged at 3,000 rpm for 10 minutes to pellet the proteins. The supernatant is transferred to a clean plate and centrifuged at 3,000 rpm for 10 minutes to pellet any remaining solids before being subjected to LC / MS / MS analysis. A reference calibration curve is generated by spiking 5 μL of compound stock in DMSO into freshly collected EDTA rat blood. An 8-point standard curve ranging from 5 nM to 10,000 nM is included in each bioanalytical unit. Standards are treated similarly to the rat pharmacokinetic samples.

[0065] Concentrations in rat pharmacokinetic samples are measured using a standardized HPLC-LC / MS / MS method in conjunction with an 8-point standard curve. The system consists of an Agilent 1200 HPLC with a binary pump coupled to a Leap CTC Pal injector, an Applied Biosystems 3200 QTrap. Compounds are chromatographed on a 20x2mm 2μm Mercury Cartridge on a Phenomenex Synergy Fusion RP equipped with a Security Guard. A gradient method is used with mobile phase A consisting of 0.1% formic acid in water and mobile phase B consisting of 0.1% formic acid in acetonitrile at flow rates varying between 0.7-0.8mL / min. Ions are generated in positive ionization mode using an electrospray ionization (ESI) interface. A unique multiple reaction monitoring (MRM) method is developed for each compound. The heated nebulizer is set at 325°C with a nebulizer current of 4.8μA. Collision energies are used to generate daughter ions in the range of 29 and 39V. The specific mass transitions for each compound used to quantify are subjected to MRM to obtain peak area ratios. The quantification limit of this method is typically 5 nM. Data is collected and analyzed using Analyst software version 1.4.2.

[0066] Blood concentration versus time data are analyzed using noncompartmental methods (WinNonlin version 5.2; model 200 for oral administration and model 202 for intravenous infusion). Absolute oral bioavailability (%) is calculated according to the following formula: (Oral AUC x IV dose) / (IV AUC x oral dose) x 100 It is calculated using:

[0067] Lymphocytopenia With a mouse: Female C57BL6 mice (Simonsen Laboratories, Gilroy CA) were housed in an ALAAC-accredited facility and the study was approved by the institution's Institutional Animal Care and Use Committee (IACUC). Animals were acclimated to the laboratory for at least 5 days prior to initiating experiments. Mice (n=3 / compound / time point) were dosed via oral gavage with compounds at 1-30 mg / kg in a vehicle consisting of 5% DMSO / 5% Thuen 20 and 90% 0.1 N HCl. Control mice were dosed PO with vehicle. Terminal whole blood samples were collected in EDTA from mice anesthetized with isoflurane via cardiac puncture. Whole blood is incubated with rat anti-mouse CD16 / CD32 (mouse BD Fc Block, #553141), PE-rat anti-mouse CD45R / B220 (BD #553089), APC-Cy7-rat anti-mouse CD8a (BD #557654), and Alexa Fluor647-rat anti-mouse CD4 (BD #557681) on ice for 30 minutes. Red blood cells are lysed using BD Pharm Lyse Lysing buffer (#555899) and leukocytes are analyzed by FACS. Lymphopenia is expressed as the % of leukocytes that are CD4 or CD8 positive T cells. The overall lymphopenic response over 24 hours is estimated by calculating the area under the effect curve (AUEC) using the linear trapezoidal method.

[0068] In rats: Male rats (Simonsen Laboratories, Gilroy CA) were housed in an ALAAC-accredited facility and the study was approved by the institution's Institutional Animal Care and Use Committee (IACUC). Animals were acclimated to the laboratory for at least 5 days prior to initiation of experiments. Rats (n=3 / compound / time point) were dosed via oral gavage with compounds at 1-30 mg / kg in a vehicle consisting of 5% DMSO / 5% Thuhn 20 and 90% 0.1 N HCL. Control mice were dosed PO with vehicle. Whole blood was collected from rats anesthetized with isoflurane via the retro-orbital sinus, with a final sample collected into EDTA by cardiac puncture. Whole blood is incubated with mouse anti-rat CD32 (BD#550271), PE-mouse anti-rat CD45R / B220 (BD#554881), PECy5-mouse anti-rat CD4 (BD #554839), and APC-mouse anti-rat CD8a (eBioscience #17-0084) for 30 minutes on ice. Red blood cells are lysed using BD Pharm Lyse Lysing buffer (#555899) and leukocytes are analyzed by BD FACSArray. Lymphopenia is expressed as the % of leukocytes that are CD4 or CD8 positive T cells. The overall lymphopenic response over 24 hours is estimated by calculating the area under the effect curve (AUEC) using the linear trapezoidal method.

[0069] Lymphocytopenia With a mouse: Female C57BL6 mice (Simonsen Laboratories, Gilroy CA) were housed in an ALAAC-accredited facility and the study was approved by the institution's Institutional Animal Care and Use Committee (IACUC). Animals were acclimated to the laboratory for at least 5 days prior to initiation of experiments. Mice (n=3 / compound / time point) were dosed via oral gavage with compounds at 1 mg / kg in a vehicle consisting of 5% DMSO / 5% Thuen 20 and 90% 0.1 N HCl. Control mice were dosed PO with vehicle. Terminal whole blood samples were collected in EDTA from mice anesthetized with isoflurane via cardiac puncture. Whole blood is incubated with rat anti-mouse CD16 / CD32 (mouse BD Fc Block, #553141), PE-rat anti-mouse CD45R / B220 (BD #553089), APC-Cy7-rat anti-mouse CD8a (BD #557654), and Alexa Fluor647-rat anti-mouse CD4 (BD #557681) on ice for 30 minutes. Red blood cells are lysed using BD Pharm Lyse Lysing buffer (#555899) and leukocytes are analyzed by FACS. Lymphopenia is expressed as the % of leukocytes that are CD4 or CD8 positive T cells. The overall lymphopenic response over 24 hours is estimated by calculating the area under the effect curve (AUEC) using the linear trapezoidal method.

[0070] In rats: Male rats (Simonsen Laboratories, Gilroy CA) were housed in an ALAAC-accredited facility and the study was approved by the institution's Institutional Animal Care and Use Committee (IACUC). Animals were acclimated to the laboratory for at least 5 days prior to initiation of the experiment. Rats (n=3 / compound / time point) were dosed via oral gavage with compounds at 1 mg / kg in a vehicle consisting of 5% DMSO / 5% Thuhn 20 and 90% 0.1N HCL. Control mice were dosed PO with vehicle. Whole blood was collected from rats anesthetized with isoflurane via the retro-orbital sinus, with a final sample collected in EDTA by cardiac puncture. Whole blood is incubated with mouse anti-rat CD32 (BD#550271), PE-mouse anti-rat CD45R / B220 (BD#554881), PECy5-mouse anti-rat CD4 (BD #554839), and APC-mouse anti-rat CD8a (eBioscience #17-0084) for 30 minutes on ice. Red blood cells are lysed using BD Pharm Lyse Lysing buffer (#555899) and leukocytes are analyzed by BD FACS Array. Lymphopenia is expressed as the % of leukocytes that are CD4 or CD8 positive T cells. The overall lymphopenic response over 24 hours is estimated by calculating the area under the effect curve (AUEC) using the linear trapezoidal method.

[0071] The various embodiments described above may be combined to provide further embodiments. All U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications, and non-patent literature mentioned herein and / or listed in the Application Data Sheet are hereby incorporated by reference in their entirety. Aspects of the embodiments may be modified to utilize concepts from various patents, applications, and publications, as necessary, to provide further embodiments. These and other variations may be made to the embodiments in light of the above detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. U.S. Provisional Application No. 63 / 001,073, filed March 27, 2020, and U.S. Provisional Application No. 63 / 018,327, filed April 30, 2020, are hereby incorporated by reference in their entirety.

Claims

1. Structural formula (I): 【Chemistry 1】 [In the formula: R is Alkyl; Alkanediyl-NR １ R ２ ; Alkanediyl-C(=O)OR １ ;or heterocyclylalkyl; R １ and R ２ are independently H or C １－４ is alkyl] or a pharma- ceutically acceptable salt, hydrate or solvate thereof.

2. 2. The compound of claim 1, wherein R is alkyl.

3. The compound of claim 2, wherein alkyl is methyl, ethyl, isopropyl or tert-butyl.

4. R is alkanediyl-NR １ R ２ 2. The compound of claim 1,

5. R １ and R ２ The compound of claim 4 , wherein is independently hydrogen or methyl.

6. R is alkanediyl-C(=O)OR １ 2. The compound of claim 1 ,

7. R １ The compound of claim 6, wherein is hydrogen or methyl.

8. 2. The compound of claim 1, wherein R is heterocyclylalkyl.

9. Heterocyclylalkyl is -(CH ２ 9. The compound according to claim 8, which is a 1-heterocycle.

10. A compound having one of the following structures, or a pharma- ceutically acceptable salt, hydrate, or solvate thereof. 【Table 1】 【Table 2】 【Table 3】 【Table 4】

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