C14 position substituted steroids and methods for their preparation

Abstract

The application discloses a C14 substituted steroid and a preparation method thereof. The method uses a steroid containing an olefin group at 14 and 15 as a starting material, and under the action of a metal catalyst, a hydrogen donor, a free radical capturing agent and a protective gas, the starting material is stirred in an organic solvent at 25-60 DEG C to obtain a novel C14 substituted steroid compound. The method has the advantages of mild reaction conditions, simple preparation process, strong substrate compatibility, good regioselectivity and the like, has great application potential, and lays a good foundation for the research on the development of novel steroid drugs.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of organic synthesis, and particularly relates to a C14 position substituted steroid and a preparation method thereof. BACKGROUND

[0002] Steroids are a class of small organic molecules with a cyclopentanoperhydrophenanthrene as the mother nucleus, which are widely present in nature and have a wide range of physiological activities, including anticancer, anti-inflammatory, immunosuppressive, progestogenic, antiandrogenic, diuretic and contraceptive activities (Salvador, J. A.; Carvalho, J. F.; Neves, M. A.; Silvestre, S. M.; Leitao, A. J.; Silva, M. M.; Sa e Melo, M. L. Nat Prod Rep 2013, 30, 324.). At present, there are more than 400 steroid drugs used in clinical, accounting for about 15% of the total number of all clinically used drugs, with an annual output of more than 1 million tons and an annual global market value of more than 100 billion US dollars (Fernandez-Cabezon, L.; Galan, B.; Garcia, J. L. Front Microbiol 2018, 9, 958). Structural modification of naturally occurring steroids to obtain new steroids can provide a solid foundation for finding new steroid drugs. The substituents of C14 in natural steroids are generally limited to hydroxyl, epoxy or methyl groups, such as the C14-hydroxyl and epoxy-substituted cardiac steroids and bufotoxins, which obviously exhibit strong physiological activity or have medicinal value ([1] Gao, H.; Popescu, R.; Koppb, B.; Wang, Z. Nat. Prod. Rep. 2011, 28, 953; [2] Zhong, Y.; Zhao, C.; Wu, W.; Fan, T.; Li, N.; Chen, M.; Duan, J.; Shi, Z. Eur. J. Med. Chem. 2020, 189, 112038). According to the literature, the unnatural steroid Lnf-209 with C14 amino substitution also exhibits strong antimuscarinic activity (Lullmann, H.; Mohr, K. J. Cardiovasc. Pharmacol. 1992, 20, 807). However, it is currently quite difficult to modify the structure of C14 of steroids, and the use of C14 olefin for structural modification of steroids is an effective means to obtain C14 functional group steroids. However, the olefin is not activated and has large steric hindrance, and in addition to the construction of carbon-oxygen bonds at C14, the construction of carbon-carbon bonds or carbon-heteroatom bonds is rarely reported.In 1983, Ponsold et al. used NBS or NIS and nucleophilic reagents to perform double functionalization on C14, 15 olefins, and obtained C14 position derivative steroids substituted with bromine or isocyanate, in 1986, they used diazomethane as an alkyl source to introduce a methylene group at C14, and obtained C14, 15 cyclopropane derivative steroid products ([1] Ponsold, K.; Wunderwald, M. J. prakt. Chem. 1983, 325, 123; [2] Prousa, R.; Schoenecker, B.; Tresselt, D.; Ponsold, K. J. prakt. Chem. 1986, 328, 55); In 2013, the Baran group reported a strategy using metal hydrogen migration to successfully introduce a fluorine atom at C14 (Science 2013, 339, 59). At present, there is still a lack of methods for synthesizing diversified C14 substituted steroids, and it is of great significance to develop a method for constructing carbon-carbon bond or carbon-heteroatom bond at C14 of steroids. SUMMARY

[0003] In order to solve the problems existing in the prior art, the present application provides a C14 position substituted steroid and a preparation method thereof. The method has mild reaction conditions, simple preparation process, strong substrate compatibility and good regioselectivity.

[0004] The technical scheme provided by the present application is as follows:

[0005] In the first aspect, the present application provides a preparation method of C14 position substituted steroid, and the steps are as follows:

[0006] Under the protection of a gas atmosphere, a steroid A containing a C14, 15 olefin group is used as a starting material, and under the action of a metal catalyst B, a hydrogen donor C and a free radical trapping agent D, the reaction is stirred in an organic solvent E at 25-60℃ until completion; after the reaction is completed, the reaction mixture is filtered, concentrated and purified by column chromatography to obtain a C14 position substituted steroid compound as shown in formula F;

[0007]

[0008] Among them:

[0009] R 1 is an alkyl, a ketone carbonyl-COR 4 , a hydroxyl, an amino, a cyano or a nitro;

[0010] R 2 is hydrogen or a hydroxyl;

[0011] R 3 is -SeR 5 or -(CH2)2R6 ;

[0012] n is the number of hydrogen, which is 1 or 2.

[0013] Further, the R 1 is a C 1～6 alkyl group; -COR 4 , wherein R 4 is a C 1～6 alkyl group. Further, the metal catalyst B is selected from one or more of Co(acac)2, Co-salen, CoCl2, Co(BF4)2, Fe(acac)3, Fe(acac)2, FeCl3, FeCl2, Fe2(ox)3 . 6H2O, Mn(acac)2, Mn(dpm)3.

[0014] Further, the hydrogen donor C is one or more of Et3SiH, PhSiH3, Ph3SiH, NaBH4, PMHS.

[0015] Further, the radical trap D is selected from one or more of TsSeR 5 , CH2=CHR 6 .

[0016] wherein R 5 is a C 6-12 aryl group or a C 6-12 heteroaryl group containing N, O, S; R 6 is an ester group, a cyano group, an aldehyde group, a nitro group, a -SO2R 7 , and the like electron-withdrawing groups, wherein the ester group is -COOR', R' is a C 1～6 alkyl group, and R 7 is a C 6-12 aryl group or a C 6-12 heteroaryl group containing N, O, S.

[0017] Further, the solvent E is selected from any one or more of methanol, ethanol, isopropanol, t-butanol, tetrahydrofuran, 2-methyltetrahydrofuran, diethyl ether, dimethyl ethylene glycol ether, methyl t-butyl ether, 1,4-dioxane, 1,3-dioxane, dichloromethane, 1,2-dichloroethane, chloroform, carbon tetrachloride, a C 4-12 saturated alkane, a C 3-12 fluorinated or chlorinated alkane, benzene, toluene, xylene, mesitylene, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, acetone, N-methylpyrrolidone, acetonitrile, a C 3-12 saturated alkyl nitrile.

[0018] Further, the molar ratio of A, B, C and D is 1: (0.1-1): (1.5-10): (1-2).

[0019] Further, in the synthesis method, the reaction time is 1-36 hours, and the reaction temperature is 25-60℃. The heating process can use oil bath (such as silicone oil, paraffin oil, etc.) or other heating methods.

[0020] Further, after the reaction is completed, the reaction product is subjected to post-treatment, including extraction, concentration and purification. The extraction process can use a separatory funnel for extraction. The concentration process can use methods such as reduced pressure distillation, for example, reduced pressure concentration with a rotary evaporator. The purification method can use column chromatography for separation and purification.

[0021] In a second aspect, the present application provides a C14-substituted steroid prepared by the method of the first aspect.

[0022] The method of the present application can prepare C14-substituted steroid compounds, and compared with the prior art, the present application has the following beneficial effects:

[0023] i) The metal catalysts involved in the present application are all inexpensive metals, and there are many types, which can be used without special treatment, and some catalysts can be obtained by simple preparation; the hydrogen donor reagents are all common commercial reagents, which can be used without special treatment; and the radical trapping reagents are mostly commercial reagents, which are stable and easy to store, and low in price, and some can be obtained by one-step reaction.

[0024] ii) The metal hydrogen transfer reaction used in the present application has very high regioselectivity, and only C14-substituted steroid products are obtained.

[0025] iii) The method of the present application has good functional group compatibility, which can be compatible with carbonyl, α, β-unsaturated double bond and other groups.

[0026] iv) The method of the present application can prepare new steroids with diversified functional groups at C14 position, which provides a solid synthetic foundation for the development of new steroid drugs, and has great application potential. DETAILED DESCRIPTION

[0027] The present application is further illustrated by examples below, and it is worth noting that the present application is not limited to the following examples.

[0028] Example 1: Preparation of compounds F1 and F2

[0029]

[0030] To a reaction tube, which was dried and equipped with a magnetic stir bar, was added compound A1 (20.0 mg, 0.06 mmol), cobalt acetylacetonate (16.4 mg, 0.06 mmol) and p-tolylsulfonyl phenyl selenide (49.6 mg, 0.15 mmol) and super dry dioxane solvent (400 μί) under argon atmosphere. After stirring for 2 min, triethylsilane (102 μί, 0.64 mmol) and tert-butyl hydroperoxide (12 μί, 0.06 mmol) were added to it and stirred at room temperature overnight. After completion of the reaction, the solid was filtered off using a short silica gel column and the silica gel column was washed with ethyl acetate and the collected solution was concentrated under reduced pressure to remove the solvent. Finally, the crude product was isolated and purified using column chromatography to obtain F1 (9.7 mg, 33%, 41% recovery yield) and F2 (8.2 mg, 27%, 34% recovery yield) as white solids. 1 H NMR (400 MHz, CDC13) δ 7.67 - 7.58 (m, 2H), 7.41 - 7.30 (m, 1H), 7.32 - 7.25 (m, 2H), 5.80 (s, 1H), 3.98 (t, J = 9.0 Hz, 1H), 2.53 - 2.34 (m, 4H), 2.18 (s, 3H), 2.17 - 2.01 (m, 4H), 1.96 - 1.58 (m, 8H), 1.55 - 1.48 (m, 1H), 1.34 - 1.28 (m, 1H), 1.26 (s, 3H), 0.90 (s, 3H); 13 C NMR (151 MHz, CDC13) δ 209.9, 199.5, 170.4, 138.5, 129.08, 128.9, 128.9, 124.2, 79.5, 61.4, 49.9, 47.9, 41.7, 39.0, 35.8, 34.1, 32.7, 32.6, 31.5, 31.4, 31.1, 22.6, 20.0, 17.7, 17.4. F2: 1 H NMR (400 MHz, CDC13) δ 7.87 - 7.48 (m, 2H), 7.35 - 7.28 (m, 1H), 5.70 (s, 1H), 2.71 - 2.61 (m, 1H), 2.48 - 2.32 (m, 1H), 2.30 (s, 2H), 2.28 - 2.13 (m, 1H), 2.10 - 1.94 (m, 2H), 1.88 - 1.75 (m, 2H), 1.67 (td, J = 13.8, 5.8 Hz, 1H), 1.55 - 1.46 (m, 0H), 1.44 (s, 2H), 1.34 (ddd, J = 21.4, 12.1, 3.2 Hz, 1H), 1.19 (td, J = 12.6, 4.2 Hz, 1H), 1.03 (s, 2H); 13CNMR (151 MHz, CDC13) δ 209.5, 199.4, 170.5, 138.3, 129.3, 128.9, 128.7, 123.9, 74.1, 63.7, 51.3, 49.6, 42.4, 42.0, 39.2, 35.8, 34.0, 33.2, 32.4, 32.0, 31.3, 24.3, 22.7, 20.9, 17.5.

[0031] Example 2: Preparation of compound F3

[0032]

[0033] To a reaction tube, dried and equipped with a magnetic stir bar, under an argon atmosphere, were sequentially added compound Al (10 mg, 0.03 mmol), iron acetylacetonate (11.3 mg, 0.03 mmol) and super-dry dichloroethane (240 μί) and ethylene glycol (50 μί). After 2 min of stirring, methyl acrylate (2.9 μί, 0.03 mmol) and phenylsilane (7.1 μί, 0.048 mmol) were sequentially added at room temperature. The reaction was then warmed to 60 °C and stirring was continued for 2 h, then cooled to room temperature, washed with sodium sulfite and extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate, filtered and the solvent was removed under reduced pressure. Finally, the crude product was purified by column chromatography to give compound F3 (1.5 mg, 12% yield) as a white solid. 1 H NMR (400 MHz, CDC13) δ 5.72 (s, 1H), 3.68 (s, 3H), 2.76 (t, J = 8.6 Hz, 1H), 2.48 - 2.25 (m, 6H), 2.22 - 2.18 (m, 1H), 2.16 (s, 3H), 2.13 - 2.01 (m, 2H), 1.95 - 1.82 (m, 2H), 1.80 - 1.60 (m, 5H), 1.54 - 1.46 (m, 1H), 1.41 - 1.18 (m, 5H), 1.16 (s, 3H), 1.08 (s, 3H); 13 C NMR (151 MHz, CDC13) δ 211.7, 199.6, 174.4, 170.6, 123.9, 77.4, 77.2, 76.9, 62.8, 51.9, 49.8, 48.6, 48.0, 42.7, 39.0, 37.6, 36.0, 34.0, 33.5, 33.3, 31.1, 30.4, 29.8, 29.0, 24.2, 21.8, 19.3, 17.8.

[0034] Example 3: Preparation of compounds F4 and F5

[0035]

[0036] To a dry reaction tube equipped with a magnetic stir bar, compound A2 (30.0 mg, 0.1 mmol), cobalt acetylacetonate (24.6 mg, 0.1 mmol) and tosyl phenyl selenide (74 mg, 0.24 mmol) and ultradry dioxane solvent (1 mL) were added under argon atmosphere. After stirring for 2 min, triethylsilane (150 μL, 0.96 mmol) and tert-butyl hydroperoxide (18 μL, 0.1 mmol, 5.5 M in decane) were added and stirred at room temperature overnight. After completion of the reaction, the solid was filtered off using a short silica gel column and the silica gel column was washed with ethyl acetate and the collected solution was concentrated under reduced pressure to remove the solvent. Finally, the crude product was isolated and purified using column chromatography to obtain F4 (24 mg, yield 53%, recovery yield 75%) and F5 (6.2 mg, yield 14%, recovery yield 19% brsm) as white solids. F4: 1 H NMR (600 MHz, CDC13) δ 7.68 - 7.62 (m, 2H), 7.39 - 7.33 (m, 1H), 7.28 (t, J = 7.6 Hz, 2H), 3.97 (t, J = 9.0 Hz, 1H), 2.96 (t, J = 14.3 Hz, 1H), 2.44 (td, J = 14.7, 5.5 Hz, 1H), 2.33 (td, J = 11.9, 5.4 Hz, 1H), 2.29 - 2.19 (m, 3H), 2.18 (s, 3H), 2.12 (ddd, J = 15.0, 4.6, 2.3 Hz, 1H), 2.05 (m, 2H), 1.97 (tt, J = 13.8, 4.7 Hz, 1H), 1.93 - 1.84 (m, 3H), 1.62 - 1.57 (m, 1H), 1.55 - 1.34 (m, 6H), 1.20 (dtd, J = 14.1, 9.2, 7.1 Hz, 1H), 1.08 (s, 3H), 0.88 (s, 3H); 13 C NMR (151 MHz, CDC13) δ 213.1, 210.0, 138.5, 129.3, 128.9, 128.9, 81.7, 61.6, 50.3, 44.8, 42.8, 41.5, 37.5, 37.3, 35.5, 35.1, 33.2, 31.6, 31.3, 26.3, 24.5, 22.6, 22.6, 20.3, 17.7. F5: 1H NMR (400 MHz, CDC13) δ 7.82 - 7.73 (m, 2H), 7.37 - 7.27 (m, 3H), 2.71 - 2.55 (m, 2H), 2.51 - 2.33 (m, 3H), 2.31 (s, 3H), 2.21 - 2.07 (m, 2H), 2.05 - 1.95 (m, 3H), 1.90 - 1.64 (m, 7H), 1.48 - 1.42 (m, 1H), 1.40 (s, 3H), 1.35 - 1.19 (m, 4H), 0.90 (s, 3H); 13 CNMR (151 MHz, CDC13) δ 212.9, 209.5, 138.2, 129.5, 128.8, 128.5, 74.7, 64.1, 51.8, 43.9, 42.9, 42.4, 42.3, 37.2, 37.0, 36.8, 35.9, 32.0, 31.9, 26.9, 24.8, 24.2, 22.6, 22.4, 21.1.

[0037] Example 4: Preparation of compounds F6 and F7

[0038]

[0039] To a reaction tube, dry and equipped with a magnetic stir bar, under argon atmosphere, were successively added compound A2 (50 mg, 0.16 mmol), iron acetylacetonate (56 mg, 0.16 mmol) and super-dry dichloroethane (1.2 mL) and ethylene glycol (300 μί). After 2 min of stirring, methyl acrylate (14.5 μί, 0.16 mmol) and phenylsilane (36 μί, 0.24 mmol) were successively added at room temperature. The reaction was then warmed to 60°C and stirred for 2 h, then cooled to room temperature, washed with sodium sulfite and extracted with dichloromethane. The organic phase was dried over anhydrous sodium sulfate, filtered and the solvent was removed under reduced pressure. The crude product was finally purified by column chromatography to give compounds F6 (2.5 mg, 4% yield) and F7 (4.0 mg, 6% yield) as white solids. F6: 1H NMR (600 MHz, CDC13) δ 3.69 (s, 3 H), 3.13 (dd, J = 10.3, 7.8 Hz, 1 H), 2.62 (t, J = 14.3 Hz, 1 H), 2.47 (ddd, J = 16.6, 12.5, 4.4 Hz, 1 H), 2.42 - 2.30 (m, 2 H), 2.26 - 2.15 (m, 2 H), 2.14 (s, 3 H), 2.13 - 1.97 (m, 3 H), 1.96 - 1.76 (m, 4 H), 1.75 - 1.58 (m, 3 H), 1.54 - 1.27 (m, 7 H), 1.26 (s, 3 H), 1.24 - 1.09 (m, 2 H), 0.99 (s, 3 H); 13 C NMR (151 MHz, CDC13) δ 213.0, 210.4, 174.5, 62.0, 51.9, 51.4, 47.7, 43.8, 42.3, 37.7, 37.2, 36.9, 35.4, 34.2, 33.0, 32.3, 31.8, 31.2, 31.0, 26.9, 22.7, 22.2, 22.1, 21.9, 21.0. F7: 1 H NMR (600 MHz, CDC13) δ 3.68 (s, 3 H), 2.76 (dd, J = 9.4, 7.7 Hz, 1 H), 2.62 (dd, J = 15.4, 13.1 Hz, 1 H), 2.41 - 2.25 (m, 3 H), 2.22 - 2.16 (m, 1 H), 2.16 (s, 3 H), 2.13 - 1.95 (m, 5 H), 1.89 - 1.73 (m, 4 H), 1.70 - 1.57 (m, 3 H), 1.57 - 1.50 (m, 2 H), 1.50 - 1.37 (m, 3 H), 1.32 - 1.17 (m, 3 H), 1.05 (s, 3 H), 0.99 (s, 3 H); 13 C NMR (151 MHz, CDC13) δ 213.1, 211.7, 174.6, 63.1, 51.8, 49.9, 48.9, 43.7, 43.1, 42.2, 37.6, 37.3, 36.9, 35.5, 34.7, 33.4, 33.2, 31.0, 30.4, 26.9, 24.2, 22.8, 22.5, 22.0, 19.4.

[0040] The above description is merely preferred specific embodiments of the application, but the scope of the protection of the application is not limited thereto, any modification, equivalent replacement and improvement made by any person skilled in the art within the technical scope disclosed by the application should be included in the scope of the protection of the application.

Claims

1. A method for preparing a C14-substituted steroid, characterized in that, The steps are as follows: Under an argon atmosphere, 0.03 mmol of compound A1, 0.03 mmol of ferric acetylacetone, 240 μL of ultradry dichloroethane, and 50 μL of ethylene glycol were added sequentially to a dry reaction tube equipped with a magnetic stirrer. After stirring for 2 min, 0.03 mmol of methyl acrylate and 0.048 mmol of phenylsilane were added sequentially at room temperature. The reaction was then heated to 60 °C. o C, and stirred continuously for 2 h, then cooled to room temperature, washed with sodium sulfite, and extracted with dichloromethane; the obtained organic phase was dried with anhydrous sodium sulfate and filtered, the solvent was removed by vacuum distillation, and finally the crude product was purified by column chromatography to obtain white solid compound F3; 。

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