An intermediate for synthesizing TYK2 inhibitors and its preparation method and use

Abstract

The present invention provides an intermediate for synthesizing a TYK2 inhibitor, a preparation method and use thereof, and belongs to the pharmaceutical field. The present invention provides compounds shown in formula II and formula III, which can be used to synthesize the above-mentioned TYK2 inhibitor and are new intermediates for synthesizing TYK2 inhibitors. The method for preparing a TYK2 inhibitor using the compound shown in formula II or formula III of the present invention as a raw material has short steps, mild reaction conditions, simple post-treatment and purification, high conversion rate, cheap and easy-to-obtain raw materials, and is suitable for industrial production.

Description

Technical Field

[0001] The invention belongs to the field of pharmaceuticals, and particularly relates to a new intermediate for synthesizing a TYK2 inhibitor, and a preparation method and use of the intermediate. Background Art

[0002] Cytokines play an important role in regulating immunity and inflammation. Janus kinase (JAK) is an intracellular non-receptor tyrosine kinase that mediates the process of transmitting various cytokine signals from the extracellular space to the cell nucleus. The JAK kinase family is divided into four subtypes: JAK1, JAK2, JAK3 and TYK2, and each subtype mediates different types of cytokine signaling pathways. JAK1, JAK2 and TYK2 are expressed in various tissue cells of the human body, and JAK3 is mainly expressed in various hematopoietic tissue cells.

[0003] TYK2 is the earliest subtype discovered in the JAK family. Currently, multiple cytokine signaling pathways that require TYK2 to participate in conduction have been discovered, including interleukins (IL) and interferons (IFN) with different subtypes. In these signaling pathways, TYK2 is coupled to transmembrane cytokine receptor proteins including IFNAR1, IL-12Rβ1, IL-10R2, and IL-13Rα1, and forms different cytokine receptor complexes through heterodimerization with another receptor chain formed by JAK1 or JAK2, providing binding sites required for STAT binding. Different cytokines, including IFN-α, IL-6, IL-12, and IL-23, activate specific downstream STAT proteins by utilizing different cytokine receptor complexes. Some cytokines, through TYK2-mediated signaling pathways, enable helper T cells Th17, Th1, B cells, or bone marrow cells to function in autoimmune diseases and chronic inflammatory diseases including systemic lupus erythematosus, psoriasis, lupus nephritis, Sjögren's disease, Crohn's disease, systemic sclerosis, etc. Some studies have shown that TYK2 deletion mutations can effectively inhibit the occurrence of immune diseases such as allergies, autoimmunity and inflammation. For example, IL-23 plays a vital role in the development of psoriasis. The latest studies have shown that the pathogenesis of psoriasis is that endogenous unknown antigens activate antigen-presenting cells APC to secrete IL-23, and IL-23 activates Th17 cells to secrete IL-17 and other cytokines, inducing keratinocyte differentiation and division and secretion of IL-23, further stimulating verification and keratinocyte proliferation to produce psoriasis. TYK2 and JAK2 jointly mediate the downstream signaling pathway of IL-23. Inhibition of JAK2 can lead to anemia and other blood-related side effects. Therefore, targeting TYK2 is a good strategy to inhibit the IL-23 signaling pathway for the treatment of psoriasis.

[0004] The ATP binding sites of all kinase group members often have a high degree of homology, among which TYK2 has a higher similarity with the ATP binding sites of other members of the JAK family. Currently, the FDA-approved full-JAK family kinase inhibitors (including Tofacitinib) can act on the ATP binding pocket of TYK2, and can also bind well to JAK1, 2, and 3 subtypes. Although these inhibitors enhance their efficacy by inhibiting the activity of other subtypes such as JAK1, JAK2 and JAK3, they also lead to more serious side effects, including infection, tuberculosis, tumors, anemia, liver damage, and increased cholesterol. Since JAK2 activity is related to red blood cell differentiation and lipid metabolism, the above-mentioned adverse reactions such as anemia are believed to be related to the lack of selectivity of Tofacitinib for JAK2, which is caused by the non-selective inhibition of the drug. At present, the use of ATP-competitive TYK2 inhibitors in clinical practice is severely restricted due to their serious side effects. Developing a small molecule inhibitor with high selectivity and specificity for TYK2 and a method for synthesizing the small molecule inhibitor will effectively increase the therapeutic window of the drug and is of great significance for improving the clinical use of TYK2 inhibitors. Summary of the invention

[0005] The purpose of the present invention is to provide a new intermediate for synthesizing a TYK2 inhibitor, as well as a preparation method and use of the intermediate.

[0006] The present invention provides a compound represented by formula II, or a salt thereof:

[0007]

[0008] Among them, R 1a is halogen, R 2a is C1-4 alkyl, R 3a It is an amino protecting group.

[0009] Furthermore, R 1a is chlorine, R 2a It is ethyl.

[0010] Further, the compound is:

[0011]

[0012] The present invention also provides a compound represented by formula III, or a salt thereof:

[0013]

[0014] Among them, R 1b is halogen, R 2b is C1-4 alkyl, R 3b For hydrogen.

[0015] Furthermore, R 1b is chlorine, R 2b It is ethyl.

[0016] Further, the compound is:

[0017]

[0018] The present invention also provides a method for preparing the compound represented by formula II, the method comprising the following steps:

[0019] (a) Compound 1 reacts with compound 2' to obtain compound 3';

[0020] (b) Compound 3' reacts with a halogenating agent to obtain compound 4';

[0021] (c) reacting compound 4' with an oxidizing agent to obtain compound 5';

[0022] (d) Compound 5' undergoes reductive amination and cyclization to obtain a compound of formula II.

[0023] Further, in step (a), the molar ratio of compound 1 to compound 2' is (38-58): (22-42), the reaction temperature is 60-100°C, the reaction time is 4-20 hours, the reaction solvent is an alcohol solvent, and the reaction is carried out in the presence of a base;

[0024] In step (b), the halogenating agent is one or more of phosphorus trihalide, phosphorus pentahalide, phosphorus oxyhalide, and sulfoxide halide, the molar ratio of compound 3' to the halogenating agent is (17-37): (100-500), the reaction temperature is 60-140° C., the reaction time is 4-12 hours, and the reaction is carried out in the presence of an acid binding agent;

[0025] In step (c), the oxidizing agent is one or more of hydrogen peroxide, sodium periodate, manganese dioxide, and potassium permanganate, the molar ratio of compound 4' to the oxidizing agent is 1:(1-3), the reaction temperature is 15-35°C, the reaction time is 1-5 hours, the reaction solvent is an organic solvent, water or a mixed liquid of the two, and the reaction is carried out in the presence of a catalyst;

[0026] In step (d), the reductive amination reaction and the cyclization reaction are carried out with compound 5', an amino protecting agent and sodium cyanoborohydride as raw materials, the molar ratio of compound 5', amino protecting agent and sodium cyanoborohydride is 18:(15-21):(19-25), the reaction temperature is 15-35°C, the reaction time is 1-6 hours, the reaction solvent is an organic solvent, and the reaction is carried out in the presence of an acid.

[0027] Furthermore, in step (a), the molar ratio of compound 1 to compound 2' is 48:32, the reaction time is overnight, the reaction temperature is 80°C, the alcohol solvent is ethanol, and the base is sodium methoxide;

[0028] In step (b), the halogenating agent is phosphorus trihalide, the molar ratio of compound 3' to the halogenating agent is 27:376, the reaction temperature is 100° C., the reaction time is 8 hours, and the acid binding agent is N,N-diisopropylethylamine;

[0029] In step (c), the oxidizing agent is sodium periodate, the molar ratio of compound 4' to the oxidizing agent is 1:2, the reaction temperature is room temperature, the reaction time is 3 hours, the reaction solvent is a mixed liquid of tetrahydrofuran and water, and the catalyst is potassium osmate;

[0030] In step (d), the molar ratio of the compound 5', the amino protecting agent and sodium cyanoborohydride is 18:18:22, the reaction temperature is room temperature, the reaction time is 3 to 4 hours, the organic solvent is 1,2-dichloroethane, and the acid is glacial acetic acid.

[0031] The present invention also provides a method for preparing the compound represented by formula III, the method comprising the following steps:

[0032]

[0033] (1) Prepare the compound represented by formula II according to the above method;

[0034] (2) The compound represented by formula II reacts with a deprotecting agent to obtain a compound represented by formula III.

[0035] The present invention also provides the use of the compound represented by formula II or the compound represented by formula III in the preparation of a TYK2 inhibitor, wherein the TYK2 inhibitor is one of the following compounds:

[0036]

[0037] The present invention also provides a method for preparing the above TYK2 inhibitor, the method comprising the following steps:

[0038]

[0039] (i) reacting the compound represented by formula II with tributyltin oxide to obtain the compound represented by formula II-1;

[0040] (ii) reacting the compound represented by formula II-1 with (1R, 2S)-2-fluorocyclopropylamine or a salt thereof to obtain a compound represented by formula II-2;

[0041] (iii) reacting the compound represented by formula II-2 with compound RH to obtain a compound represented by formula II-3; wherein R is

[0042] (iv) reacting the compound represented by formula II-3 with a deprotection agent to obtain a TYK2 inhibitor.

[0043] Furthermore, in step (i), the molar ratio of the compound represented by formula II to tributyltin oxide is (10-16):(40-50), the reaction temperature is 90-130° C., the reaction time is 2-6 days, and the reaction solvent is an organic solvent;

[0044] In step (ii), the molar ratio of the compound represented by formula II-1 to (1R, 2S)-2-fluorocyclopropylamine or its salt is (8-13): (9-14), the reaction temperature is 15-35° C., the reaction time is 10-22 hours, the reaction solvent is an organic solvent, and the reaction is carried out in the presence of a condensing agent and a base;

[0045] In step (iii), the molar ratio of the compound represented by formula II-2 to compound RH is 1:(1-3), the reaction temperature is 60-100°C, the time is 10-22 hours, the reaction solvent is an organic solvent, and the reaction is carried out in the presence of a palladium catalyst, a phosphorus ligand and a base.

[0046] Furthermore, in step (i), the molar ratio of the compound represented by formula II to tributyltin oxide is 13:45.3, the reaction temperature is 110° C., the reaction time is 4 days, and the organic solvent is toluene;

[0047] In step (ii), the molar ratio of the compound represented by formula II-1 to (1R, 2S)-2-fluorocyclopropylamine or its salt is 10.6:11.2, the salt of (1R, 2S)-2-fluorocyclopropylamine is (1R, 2S)-2-fluorocyclopropylamine p-toluenesulfonate, the reaction temperature is room temperature, the reaction time is 16 hours, the organic solvent is dichloromethane, the condensation agent is 2-(7-azabenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate, and the base is triethylamine;

[0048] In step (iii), the molar ratio of the compound represented by formula II-2 to compound RH is 1:2, the reaction temperature is 80°C, the reaction time is 16 hours, the organic solvent is 1,4-dioxane, the palladium catalyst is tris(dibenzylideneacetone)dipalladium, the phosphorus ligand is 4,5-bis(diphenylphosphine)-9,9-dimethyloxanthene, and the base is cesium carbonate.

[0049] Further, in step (iii), compound RH is prepared according to the following method: With compound XR y Reaction to obtain compound RH; wherein X is halogen, R y for

[0050] In the present invention, room temperature refers to 25±2°C.

[0051] PMB is an amino protecting group: p-methoxybenzyl.

[0052] Halogen refers to fluorine, chlorine, bromine or iodine.

[0053] The phosphorus oxyhalide refers to phosphorus oxytrifluoride, phosphorus oxychloride, phosphorus oxybromide or phosphorus oxytriiodide.

[0054] The phosphorus trihalide refers to phosphorus trifluoride, phosphorus trichloride, phosphorus tribromide or phosphorus triiodide.

[0055] The phosphorus pentahalide refers to phosphorus pentafluoride, phosphorus pentachloride, phosphorus pentabromide or phosphorus pentaiodide.

[0056] The sulfoxide halide refers to sulfoxide fluoride, sulfoxide chloride, sulfoxide bromide or sulfoxide iodide.

[0057] The reaction time of overnight means the reaction time is 8 to 16 hours.

[0058] Unless otherwise specified, the reactions of the present invention are all carried out under continuous magnetic stirring and dry nitrogen, the solvents are all dry solvents, and the temperature unit is °C.

[0059] Compared with the prior art, the present invention has achieved the following beneficial effects:

[0060] 1. The present invention has developed new compounds that can competitively bind to the JH2 domain of the kinase TYK2: compounds a, b, and c. These compounds can competitively bind to the JH2 domain of the kinase TYK2, can be used to prepare TYK2 inhibitors with high selectivity for TYK2, and can be used to treat diseases related to TYK2 kinase dysfunction, such as cancer, bone disease, inflammatory disease, immune disease, nervous system disease, metabolic disease, respiratory disease, heart disease and other diseases.

[0061] 2. The present invention provides compounds of formula II and formula III, which can be used to synthesize the above-mentioned TYK2 inhibitors and are new intermediates for synthesizing TYK2 inhibitors. The method for preparing TYK2 inhibitors using the compounds of formula II or formula III of the present invention as raw materials has short steps, mild reaction conditions, simple post-treatment and purification, high conversion rate, and cheap and readily available raw materials.

[0062] 3. The present invention also provides a method for preparing the compounds of formula II and formula III. The method has cheap and readily available raw materials, mild reaction conditions, simple post-treatment and purification, high product yield and purity, and is suitable for industrial production.

[0063] Obviously, according to the above contents of the present invention, in accordance with common technical knowledge and customary means in the art, without departing from the above basic technical ideas of the present invention, other various forms of modification, replacement or change may be made.

[0064] The above contents of the present invention are further described in detail below through specific implementation methods in the form of embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples. All technologies realized based on the above contents of the present invention belong to the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of ethyl 5-chloro-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidine-3-carboxylate. DETAILED DESCRIPTION

[0066] The raw materials and equipment used in the present invention are all known products, which are obtained by purchasing commercially available products.

[0067] Example 1. Preparation of 5-chloro-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidine-3-carboxylic acid ethyl ester

[0068] Ethyl 5-chloro-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidine-3-carboxylate (i.e., the compound shown in Formula I) was synthesized according to the following route:

[0069]

[0070] Step 1: Preparation of ethyl 6-allyl-5,7-dihydroxypyrazolo[1,5-a]pyrimidine-3-carboxylate

[0071]

[0072] Dissolve 2-allylmalonic acid diethyl ester (i.e., compound 1, 9.7 g, 48 mmol), 3-amino-4-ethoxycarbonylpyrazole (i.e., compound 2, 5 g, 32 mmol), and sodium methoxide (4.5 g, 82.5 mmol) in ethanol (100 mL), and react at 80°C overnight. After the reaction, cool to room temperature, adjust the pH of the reaction solution to 2 with 1 mol / L hydrochloric acid, filter, and collect the filter cake to obtain compound 6-allyl-5,7-dihydroxypyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester (i.e., compound 3, 7.1 g, with a yield of 83%).

[0073] Step 2: Preparation of ethyl 6-allyl-5,7-dichloropyrazolo[1,5-a]pyrimidine-3-carboxylate

[0074]

[0075] 6-allyl-5,7-dihydroxypyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester (i.e., compound 3, 7.1 g, 27 mmol) was dissolved in phosphorus oxychloride (35 mL, 376 mmol), and N,N-diisopropylethylamine (7.0 g, 54 mmol) was slowly added dropwise. After the addition was completed, the reaction solution was reacted at 100°C for 8 h. After the reaction was completed, it was cooled to room temperature and concentrated under reduced pressure to remove excess phosphorus oxychloride. The residue was poured into ice water and the pH was adjusted to 8 with saturated sodium bicarbonate aqueous solution. The organic phases were extracted 3 times with ethyl acetate, and the organic phases were combined and washed with saturated sodium chloride aqueous solution, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and separated by column chromatography (eluent: ethyl acetate: petroleum ether = 5:1-1:1) to obtain 6-allyl-5,7-dichloropyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester (i.e., compound 4, 6.5 g, yield 81%).

[0076] Step 3: Preparation of ethyl 5,7-dichloro-6-(2-oxoethyl)pyrazolo[1,5-a]pyrimidine-3-carboxylate

[0077]

[0078] Dissolve 6-allyl-5,7-dichloropyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester (i.e., compound 4, 6.5 g, 22 mmol) in 120 mL (THF / H2O=3 / 1, v / v). Cool to 0°C with ice water, add catalytic equivalent potassium osmate (67 mg, 0.22 mmol) and sodium periodate (9.4 g, 44 mmol), and slowly warm to room temperature for 3 h. After the reaction, add 100 mL of saturated sodium sulfite solution, extract 3 times with ethyl acetate, combine the organic phases, wash with saturated sodium chloride aqueous solution, dry with anhydrous sodium sulfate, concentrate under reduced pressure, and separate and purify by column chromatography (eluent: ethyl acetate: petroleum ether=5:1-1:1) to obtain 5,7-dichloro-6-(2-oxoethyl)pyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester (i.e., compound 5, 5.5 g, yield 85%).

[0079] Step 4: Preparation of ethyl 5-chloro-8-(4-methoxybenzyl)-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidine-3-carboxylate

[0080]

[0081] Dissolve 5,7-dichloro-6-(2-oxoethyl)pyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester (i.e., compound 5, 5.5 g, 18 mmol) and 4-methoxybenzylamine (2.5 g, 18 mmol) in 1,2-dichloroethane (100 mL), add a catalytic amount of glacial acetic acid (55 mg, 0.91 mmol), and stir at room temperature for 1 hour. Then, add sodium cyanoborohydride (1.38 g, 22 mmol) and stir at room temperature for 3 hours. After the reaction, 100 mL of water was added, and the mixture was extracted with dichloromethane three times. The organic phases were combined and washed with a saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and separated and purified by column chromatography (eluent: ethyl acetate: petroleum ether = 3:1-1:1) to obtain 5-chloro-8-(4-methoxybenzyl)-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrole[3,2-e]pyrimidine-3-carboxylic acid ethyl ester (i.e., compound 6, 4.8 g, yield: 69%).

[0082] Step 5: Preparation of ethyl 5-chloro-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidine-3-carboxylate

[0083]

[0084] 5-Chloro-8-(4-methoxybenzyl)-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidine-3-carboxylic acid ethyl ester (i.e., compound 6, 4.8 g, 12.4 mmol) was dissolved in 50 mL of trifluoroacetic acid and stirred at 50°C for 2 hours. After the reaction, the excess trifluoroacetic acid was removed by vacuum concentration, and 100 mL of ice water was added to the residue. The mixture was extracted with ethyl acetate three times, the organic phases were combined and washed with saturated sodium chloride aqueous solution, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and separated and purified by column chromatography (dichloromethane: methanol = 20:1-10:1) to obtain 5-chloro-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidine-3-carboxylic acid ethyl ester (i.e., the compound shown in formula I, 3 g, yield 91%, purity 95%).

[0085] The H NMR spectrum of ethyl 5-chloro-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidine-3-carboxylate is shown in Figure 1 shown.

[0086] The total yield of the compound of formula I in this embodiment (based on compound 1) is: 83%×81%×85%×69%×91%=35.88%.

[0087] Example 2: Preparation of TYK2 inhibitor using 5-chloro-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidine-3-carboxylic acid ethyl ester

[0088] (I) Preparation of TYK2 inhibitor: Compound a

[0089]

[0090] Step 1: Preparation of 3-amino-5'-(N,N-dimethylamino)-2H-[1,2-bipyridyl]-2-one

[0091]

[0092] 3-amino-2-hydroxypyridine (0.5 g, 4.5 mmol), N,N'-dimethylethylenediamine (40.0 mg, 0.5 mmol), 5-(N,N-dimethylamino)-2-bromopyridine (1.0 g, 5.0 mmol), N,N-dimethylformamide (15 mL) were mixed in a sealed tube, followed by potassium carbonate (1.3 g, 9.1 mmol) and cuprous iodide (43 mg, 0.2 mmol), nitrogen replacement, sealed heating at 120 ° C overnight. After completion, the filtrate was filtered and collected, the filtrate was diluted with ethyl acetate, washed with water and saturated brine in turn, dried over anhydrous sodium sulfate, concentrated under reduced pressure, and purified by silica gel column chromatography to obtain a white solid 3-amino-5'-(N,N-dimethylamino)-2H-[1,2-bipyridine]-2-one (0.3 g, yield 28.7%).

[0093] MS m / z(ESI):231[M+H] + .

[0094] Step 2: Preparation of 5-chloro-8-p-methoxybenzyl-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidine-3-carboxylic acid

[0095]

[0096] 5-Chloro-8-p-methoxybenzyl-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidine-3-carboxylic acid ethyl ester (5.0 g, 13.0 mmol) and tributyltin oxide (27.0 g, 45.3 mmol) were dissolved in a round-bottom flask with dry toluene (50 mL), replaced with nitrogen for protection, and refluxed at 110°C for four days. After completion, the reaction was concentrated and purified by preparative liquid phase to obtain a red solid 5-chloro-8-p-methoxybenzyl-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidine-3-carboxylic acid (3.5 g, yield 76.1%).

[0097] MS m / z(ESI):359,361[M+H] + .

[0098] Step 3: Preparation of 5-chloro-N-((1S, 2R)-2-fluorocyclopropyl)-8-p-methoxybenzyl-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidine-3-carboxamide

[0099]

[0100] 5-Chloro-8-p-methoxybenzyl-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidine-3-carboxylic acid (3.8 g, 10.6 mmol) was dissolved in dichloromethane (300 mL), followed by the addition of 2-(7-azabenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate (4.85 mg, 12.7 mmol), triethylamine (6.6 mg, 26.5 mmol), and then (1R,2S)-2-fluorocyclopropylamine p-toluenesulfonate (2.76 g, 11.2 mmol). After completion, the mixture was protected by nitrogen and reacted at room temperature for 16 hours. After the reaction was completed, the system was concentrated and purified by silica gel column chromatography to obtain a red solid 5-chloro-N-((1S, 2R)-2-fluorocyclopropyl)-8-p-methoxybenzyl-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidine-3-carboxamide (2.1 g, yield was 49.5%).

[0101] MS m / z(ESI):416,418[M+H] + .

[0102] Step 4: Preparation of 5-((5'-(N,N-dimethylamino)-2-oxo-2H-[1,2'-bipyridyl]-3-yl)amino)-N-((1R,2S)-2-fluorocyclopropyl)-8-p-methoxybenzyl-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidine-3-carboxamide

[0103]

[0104] 5-Chloro-N-((1S, 2R)-2-fluorocyclopropyl)-8-p-methoxybenzyl-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidine-3-carboxamide (60.0 mg, 0.1 mmol) and 3-amino-5'-(N,N-dimethylamino)-2H-[1,2-bipyridine]-2-one (36.6 mg, 0.2 mmol) were dissolved in 1,4-dioxane (3 mL). Cesium carbonate (99.0 mg, 0.3 mmol), tris(dibenzylideneacetone)dipalladium (26.0 mg, 0.3 mmol) and 4,5-bis(diphenylphosphine)-9,9-dimethylxanthene (16.0 mg, 0.3 mmol) were added to the system. The system was heated to 80°C under nitrogen protection for 16 hours. After completion, the product was extracted with ethyl acetate, the organic layer was collected and concentrated, and purified by silica gel column chromatography to obtain 5-((5'-(N,N-dimethylamino)-2-oxo-2H-[1,2'-bipyridyl]-3-yl)amino)-N-((1R,2S)-2-fluorocyclopropyl)-8-p-methoxybenzyl-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidine-3-carboxamide (50.0 mg, yield was 56.8%).

[0105] MS m / z(ESI):610[M+H] + .

[0106] Step 5: Preparation of 5-((5'-(N,N-dimethylamino)-2-oxo-2H-[1,2'-bipyridyl]-3-yl)amino)-N-((1R,2S)-2-fluorocyclopropyl)-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidine-3-carboxamide (i.e., compound a)

[0107]

[0108] 5-((5'-(N,N-dimethylamino)-2-oxo-2H-[1,2'-bipyridyl]-3-yl)amino)-N-((1R,2S)-2-fluorocyclopropyl)-8-p-methoxybenzyl-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidine-3-carboxamide (45 mg, 0.1 mmol) was dissolved in trifluoroacetic acid (3 mL) and reacted at 75 °C for 2 hours under nitrogen protection. After the reaction was completed, the system was concentrated and purified by preparative liquid phase to give a white solid 5-((5'-(N,N-dimethylamino)-2-oxo-2H-[1,2'-bipyridyl]-3-yl)amino)-N-((1R,2S)-2-fluorocyclopropyl)-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidine-3-carboxamide (17.8 mg, yield was 49.3%).

[0109] MS m / z(ESI):490[M+H] + .

[0110] (II) Synthesis of TYK2 inhibitor: Compound b

[0111]

[0112] Referring to the synthesis method of compound a, TYK2 inhibitor compound b was prepared using 5-chloro-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidine-3-carboxylic acid ethyl ester.

[0113] (III) Synthesis of TYK2 inhibitor: Compound c

[0114]

[0115] Referring to the synthesis method of compound a, TYK2 inhibitor compound c was prepared using 5-chloro-7,8-dihydro-6H-pyrazolo[1,5-a]pyrrolo[3,2-e]pyrimidine-3-carboxylic acid ethyl ester.

[0116] The beneficial effects of the present invention are demonstrated by test examples below.

[0117] Test Example 1. Control experiment for synthesis of ethyl 6-allyl-5,7-dihydroxypyrazolo[1,5-a]pyrimidine-3-carboxylate (Compound 3)

[0118] Scheme 1: Dissolve diethyl 2-allylmalonate (i.e., compound 1, 9.7 g, 48 mmol), 3-amino-4-ethoxycarbonylpyrazole (i.e., compound 2, 5 g, 32 mmol), and sodium methoxide (4.5 g, 82.5 mmol) in ethanol (100 mL), react at 60°C overnight, cool to room temperature after the reaction, adjust the pH of the reaction solution to 2 with 1 mol / L hydrochloric acid, filter and collect the filter cake to obtain compound 6-allyl-5,7-dihydroxypyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester (i.e., compound 3, 5.1 g, yield 59%).

[0119] Scheme 2: Dissolve diethyl 2-allylmalonate (i.e., compound 1, 9.7 g, 48 mmol), 3-amino-4-ethoxycarbonylpyrazole (i.e., compound 2, 5 g, 32 mmol), and sodium methoxide (4.5 g, 82.5 mmol) in ethanol (100 mL), react at 100°C overnight, cool to room temperature after the reaction, adjust the pH of the reaction solution to 2 with 1 mol / L hydrochloric acid, filter and collect the filter cake to obtain compound 6-allyl-5,7-dihydroxypyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester (i.e., compound 3, 4.9 g, yield 57%).

[0120] Scheme 3: Dissolve diethyl 2-allylmalonate (i.e., compound 1, 9.7 g, 48 mmol), 3-amino-4-ethoxycarbonylpyrazole (i.e., compound 2, 5 g, 32 mmol), and sodium tert-butoxide (9.2 g, 82.5 mmol) in ethanol (100 mL), and react at 100 °C overnight. After the reaction, cool to room temperature, adjust the pH of the reaction solution to 2 with 1 mol / L hydrochloric acid, filter, and collect the filter cake to obtain compound 6-allyl-5,7-dihydroxypyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester (i.e., compound 3, 3.6 g, with a yield of 42%).

[0121] It can be seen that compared with the above-mentioned schemes 1, 2 and 3, the yield of compound 3 synthesized by the method of the first step of Example 1 is the highest.

[0122] Test Example 2: Control experiment for synthesis of 6-allyl-5,7-dichloropyrazole[1,5-a]pyrimidine-3-carboxylic acid ethyl ester (ie, compound 4)

[0123] Scheme 1: Dissolve 6-allyl-5,7-dihydroxypyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester (i.e., compound 3, 7.1 g, 27 mmol) in phosphorus oxychloride (10 mL, 108 mmol), slowly add N,N-diisopropylethylamine (7.0 g, 54 mmol), and react at 100°C for 8 h after the addition. After the reaction is completed, cool to room temperature and concentrate under reduced pressure to remove excess phosphorus oxychloride. Pour the residue into ice water and adjust the pH to 8 with saturated sodium bicarbonate aqueous solution. Extract with ethyl acetate three times, combine the organic phases and wash with saturated sodium chloride aqueous solution, dry with anhydrous sodium sulfate, concentrate under reduced pressure, and separate by column chromatography (eluent is ethyl acetate: petroleum ether = 5:1-1:1) to obtain 6-allyl-5,7-dichloropyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester (i.e., compound 4, 4.8 g, yield is 60%).

[0124] Scheme 2: Dissolve 6-allyl-5,7-dihydroxypyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester (i.e., compound 3, 7.1 g, 27 mmol) in phosphorus oxychloride (35 mL, 376 mmol), slowly add N,N-diisopropylethylamine (7.0 g, 54 mmol), and react at 60°C for 8 h after the addition. After the reaction is completed, cool to room temperature and concentrate under reduced pressure to remove excess phosphorus oxychloride. Pour the residue into ice water and adjust the pH to 8 with saturated sodium bicarbonate aqueous solution. Extract with ethyl acetate three times, combine the organic phases and wash with saturated sodium chloride aqueous solution, dry with anhydrous sodium sulfate, concentrate under reduced pressure, and separate by column chromatography (eluent is ethyl acetate: petroleum ether = 5:1-1:1) to obtain 6-allyl-5,7-dichloropyrazolo[1,5-a]pyrimidine-3-carboxylic acid ethyl ester (i.e., compound 4, 5.3 g, yield is 66%).

[0125] It can be seen that compared with the above-mentioned schemes 1 and 2, the yield of compound 4 synthesized by the method of the second step of Example 1 is the highest.

[0126] Experimental Example 3: Study on the binding ability of the TYK2 inhibitor of the present invention to the TYK2 JH2 domain

[0127] 1. Experimental methods

[0128] The binding ability of TYK2 inhibitors (compounds a, b, and c) to the JH2 domain of TYK2 kinase was evaluated using in vitro biochemical experiments. The specific experimental steps are as follows.

[0129] The expression of the human TYK2 kinase domain (575-869 amino acids) was obtained by the insect cell-baculovirus expression system (Bac-to-BacExpression System), and the specific experimental steps were carried out according to the operating manual of Invitrogen. After centrifugation, Sf-9 insect cells infected with the virus for 66 hours were dissolved in a Buffer A solution (50mM Hepes, pH 7.7, 500mM NaCl, 25mM imidazole, 5% (v / v) glycerol, 0.1% Triton X-100, 0.5mM TCEP) with a mass ratio of 2.5:1 and protease inhibitors. After ultrasonic disruption, the supernatant was collected and purified by AKTA Explorer-100 system at 9500rpm and 4° speed for 30 minutes. The supernatant was adsorbed and eluted through a nickel affinity adsorption column (50mM Hepes, pH 7.7, 500mM NaCl, 350mM Imidazole, 5% (v / v) glycerol, 0.5mM TCEP) and further purified by size exclusion chromatography (50mM Hepes, pH 7.7, 500mM NaCl, 1mM MnCl2, 5% (v / v) glycerol, 0.5mM TCEP) and analyzed and verified using SDS-PAGE, dynamic light scattering, liquid chromatography-mass spectrometry and other methods.

[0130] The binding ability of the compounds to the JH2 domain of the purified kinase TYK2 was detected by homogeneous time-resolved fluorescence (HTRF). A reaction system solution containing 26nM fluorescein-labeled probe and 0.2nM anti-6×His-terbium-labeled antibody (20mM Hepes pH7.5, 150mM NaCl, 10mM MgCl2, 2mM DTT, 50μg / mL BSA, and 0.015% Brij 35) was added to 10μL of recombinant protein of the human TYK2 kinase domain with a His tag, so that the final concentration of the probe was 0.5nM. Then, compounds with different concentration gradients were added, incubated at room temperature for one hour, and the HTRF signal was detected using an enzyme reader. By setting up a control group with protein and a control group without protein as controls for calculation, the IC value of the compound's competitive binding to the JH2 domain of the kinase TYK2 was obtained. 50 value.

[0131] 2. Experimental results

[0132] Table 1 IC values ​​of TYK2 inhibitors for competitive binding to the JH2 domain of kinase TYK2 50 value

[0133]

[0134] It can be seen that compounds a, b and c of the present invention can competitively bind to the JH2 domain of the kinase TYK2 and can be used as TYK2 inhibitors with high selectivity for TYK2.

[0135] In summary, the present invention provides an intermediate for synthesizing a TYK2 inhibitor, a preparation method thereof, and a use thereof. The compounds shown in formula II and formula III provided by the present invention can be used to synthesize the TYK2 inhibitor of the present invention, and are new intermediates for synthesizing TYK2 inhibitors. The method for preparing a TYK2 inhibitor using the compounds shown in formula II or formula III of the present invention as raw materials has short steps, mild reaction conditions, simple post-treatment and purification, high conversion rate, cheap and readily available raw materials, and is suitable for industrial production.

Claims

1. A compound represented by formula II, or a salt thereof: in, R 1a is halogen, R 2a C 1～4 Alkyl, R 3a It is p-methoxybenzyl.

2. The compound according to claim 1, or a salt thereof, characterized in that: R 1a is chlorine, R 2a It is ethyl.

3. The compound according to claim 2, or a salt thereof, characterized in that: The compound is:

4. A method for preparing the compound according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: (a) Compound 1 reacts with compound 2' to obtain compound 3'; (b) Compound 3' reacts with a halogenating agent to obtain compound 4'; (c) reacting compound 4' with an oxidizing agent to obtain compound 5'; (d) Compound 5' undergoes reductive amination reaction and cyclization reaction to obtain a compound of formula II; In step (a), the molar ratio of compound 1 to compound 2' is (38-58): (22-42), the reaction temperature is 60-100° C., the reaction time is 4-20 hours, the reaction solvent is an alcohol solvent, and the reaction is carried out in the presence of a base; In step (b), the halogenating agent is one or more of phosphorus trihalide, phosphorus pentahalide, phosphorus oxyhalide, and sulfoxide halide, the molar ratio of compound 3' to the halogenating agent is (17-37): (100-500), the reaction temperature is 60-140° C., the reaction time is 4-12 hours, and the reaction is carried out in the presence of an acid binding agent; In step (c), the oxidizing agent is one or more of hydrogen peroxide, sodium periodate, manganese dioxide, and potassium permanganate, the molar ratio of compound 4' to the oxidizing agent is 1:(1-3), the reaction temperature is 15-35°C, the reaction time is 1-5 hours, the reaction solvent is an organic solvent, water or a mixed liquid of the two, and the reaction is carried out in the presence of a catalyst; In step (d), the reductive amination reaction and the cyclization reaction are carried out with compound 5', an amino protecting agent and sodium cyanoborohydride as raw materials, wherein the amino protecting agent is 4-methoxybenzylamine, the molar ratio of compound 5', the amino protecting agent and sodium cyanoborohydride is 18:(15-21):(19-25), the reaction temperature is 15-35°C, the reaction time is 1-6 hours, the reaction solvent is an organic solvent, and the reaction is carried out in the presence of an acid.

5. The method according to claim 4, characterized in that: In step (a), the molar ratio of compound 1 to compound 2' is 48:32, the reaction time is overnight, the reaction temperature is 80° C., the alcohol solvent is ethanol, and the base is sodium methoxide; In step (b), the halogenating agent is phosphorus trihalide, the molar ratio of compound 3' to the halogenating agent is 27:376, the reaction temperature is 100° C., the reaction time is 8 hours, and the acid binding agent is N,N-diisopropylethylamine; In step (c), the oxidizing agent is sodium periodate, the molar ratio of compound 4' to the oxidizing agent is 1:2, the reaction temperature is room temperature, the reaction time is 3 hours, the reaction solvent is a mixed liquid of tetrahydrofuran and water, and the catalyst is potassium osmate; In step (d), the molar ratio of the compound 5', the amino protecting agent and sodium cyanoborohydride is 18:18:22, the reaction temperature is room temperature, the reaction time is 3 to 4 hours, the organic solvent is 1,2-dichloroethane, and the acid is glacial acetic acid.

6. Use of the compound according to any one of claims 1 to 3 in the preparation of a TYK2 inhibitor, wherein the TYK2 inhibitor is one of the following compounds:

7. A method for preparing a TYK2 inhibitor, characterized in that: The method comprises the following steps: (i) reacting the compound represented by formula II with tributyltin oxide to obtain the compound represented by formula II-1; the compound represented by formula II is the compound described in any one of claims 1 to 3; (ii) reacting the compound represented by formula II-1 with (1R, 2S)-2-fluorocyclopropylamine or a salt thereof to obtain a compound represented by formula II-2; (iii) reacting the compound represented by formula II-2 with compound RH to obtain a compound represented by formula II-3; wherein R is (iv) reacting the compound represented by formula II-3 with a deprotection agent to obtain a TYK2 inhibitor; In step (i), the molar ratio of the compound represented by formula II to tributyltin oxide is (10-16):(40-50), the reaction temperature is 90-130° C., the reaction time is 2-6 days, and the reaction solvent is an organic solvent; In step (ii), the molar ratio of the compound represented by formula II-1 to (1R, 2S)-2-fluorocyclopropylamine or its salt is (8-13): (9-14), the reaction temperature is 15-35° C., the reaction time is 10-22 hours, the reaction solvent is an organic solvent, and the reaction is carried out in the presence of a condensing agent and a base; In step (iii), the molar ratio of the compound represented by formula II-2 to compound RH is 1:(1-3), the reaction temperature is 60-100°C, the time is 10-22 hours, the reaction solvent is an organic solvent, and the reaction is carried out in the presence of a palladium catalyst, a phosphorus ligand and a base.

8. The method according to claim 7, characterized in that: In step (i), the molar ratio of the compound represented by formula II to tributyltin oxide is 13:45.3, the reaction temperature is 110° C., the reaction time is 4 days, and the organic solvent is toluene; In step (ii), the molar ratio of the compound represented by formula II-1 to (1R, 2S)-2-fluorocyclopropylamine or its salt is 10.6:11.2, the salt of (1R, 2S)-2-fluorocyclopropylamine is (1R, 2S)-2-fluorocyclopropylamine p-toluenesulfonate, the reaction temperature is room temperature, the reaction time is 16 hours, the organic solvent is dichloromethane, the condensation agent is 2-(7-azabenzotriazole)-N,N,N',N'-tetramethyluronium hexafluorophosphate, and the base is triethylamine; In step (iii), the molar ratio of the compound represented by formula II-2 to compound RH is 1:2, the reaction temperature is 80°C, the reaction time is 16 hours, the organic solvent is 1,4-dioxane, the palladium catalyst is tris(dibenzylideneacetone)dipalladium, the phosphorus ligand is 4,5-bis(diphenylphosphine)-9,9-dimethyloxanthene, and the base is cesium carbonate.

9. The method according to any one of claims 7 to 8, characterized in that: In step (iii), compound RH is prepared according to the following method: With compound XR y Reaction to obtain compound RH; wherein X is halogen, R y for

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