A kind of forskolin ester derivative and its preparation method and application

Abstract

The present invention belongs to the technical field of pharmaceutical chemistry, and discloses a forskolin ester derivative, a preparation method thereof and an application thereof. The forskolin ester derivative has a chemical structural formula shown in formula (I), and forskolin is reacted with aromatic acid or phenylacetic acid, dicyclohexylcarbodiimide and 4-dimethylaminopyridine in dichloromethane to obtain a forskolin ester intermediate 2, and then the forskolin ester intermediate 2 is reacted with palladium acetate in tetrahydrofuran in an open reaction to perform intramolecular cyclization to obtain a forskolin ester derivative 3. The forskolin ester derivative obtained by the present invention contains an cyclopentane ether structure, and this new structure gives this type of derivative excellent anti-inflammatory activity.

Description

Technical Field

[0001] The invention belongs to the technical field of pharmaceutical chemistry, and specifically relates to a forskolin ester derivative and a preparation method and application thereof. Background Art

[0002] Forskolin (hereinafter referred to as "forskolin") is a complex hemiarthane-type plant diterpenoid. Based on its activity as a cyclic adenosine monophosphate (cAMP) cyclase activator, it is used to treat a variety of diseases. Natural forskolin is currently only found in the cork layer of the root of the endangered plant Coleus forskohlii. Forskolin analogs or derivatives reported in the literature have various pharmacological activities such as anti-tumor, anticoagulant, and antihypertensive.

[0003] Summary of the invention

[0004] In view of this, the object of the present invention is to provide a forskolin ester derivative and a preparation method and application thereof. The compound structure contains a cyclic ether structure, and this new structure gives the derivative excellent anti-inflammatory activity.

[0005] The present invention provides a forskolin ester derivative, which has a structure shown in formula (I):

[0006]

[0007] Here, R represents one of phenyl, p-chlorophenyl, p-methylphenyl, p-bromophenyl, p-fluorophenyl and benzyl.

[0008] Furthermore, the forskolin ester derivative has a structure as shown in any one of Formulae 3a to 3d:

[0009]

[0010] in,

[0011] When R is phenyl, the forskolin ester derivative is a compound having a structure shown in formula 3a;

[0012] When R is p-chlorophenyl, the forskolin ester derivative is a compound having a structure shown in Formula 3b;

[0013] When R is p-methylbenzene, the forskolin ester derivative is a compound having a structure shown in Formula 3c;

[0014] When R is benzyl, the forskolin ester derivative is a compound having a structure shown in formula 3d;

[0015] The present invention also provides a method for preparing a forskolin ester derivative, comprising the following steps:

[0016] Forskolin is reacted with aromatic acid or phenylacetic acid, dicyclohexylcarbodiimide and 4-dimethylaminopyridine in dichloromethane to obtain forskolin ester intermediate 2, and then forskolin ester intermediate 2 is reacted with palladium acetate in tetrahydrofuran to obtain forskolin ester derivative 3.

[0017] Wherein, the reaction formula of the preparation method is:

[0018]

[0019] Here, R represents one of phenyl, p-chlorophenyl, p-methylphenyl, p-bromophenyl, p-fluorophenyl and benzyl.

[0020] Specifically, the preparation method comprises the following steps:

[0021] (1) Dissolving forskolin in dichloromethane, adding aromatic acid or phenylacetic acid, dicyclohexylcarbodiimide and 4-dimethylaminopyridine to react to obtain a first reaction solution, concentrating the first reaction solution under reduced pressure, diluting with an organic solvent, washing with water, washing with saturated brine, and washing with MgSO 4 Drying, concentrating under reduced pressure, and then column chromatography to obtain a white solid forskolin ester intermediate 2, wherein the molar ratio of forskolin, aromatic acid or phenylacetic acid, dicyclohexylcarbodiimide, and 4-dimethylaminopyridine is 1:1.5:2:2;

[0022] (2) Dissolve the forskolin ester intermediate 2 in tetrahydrofuran, add palladium acetate, and react in an open state to obtain a second reaction solution. After cooling the second reaction solution, concentrate it under reduced pressure, dilute it with an organic solvent, wash it with water, wash it with saturated brine, and wash it with MgSO 4 Drying, concentrating under reduced pressure, and then column chromatography to obtain a white solid forskolin ester derivative 3, wherein the molar ratio of forskolin ester intermediate 2 to palladium acetate is 1:0.2;

[0023] Wherein, the aromatic acid is one of benzoic acid, p-toluic acid, p-chlorobenzoic acid, p-bromobenzoic acid, p-fluorobenzoic acid and phenylacetic acid.

[0024] Preferably, in step (1) of the above preparation method, the reaction temperature is 25° C. and the reaction time is 24 h.

[0025] Preferably, in step (2) of the above preparation method, the reaction temperature is 40° C. and the reaction time is 24 h.

[0026] Preferably, in the above preparation method, the organic solvent is at least one of ethyl acetate, diethyl ether and benzene.

[0027] The present invention also provides a use of the forskolin ester derivatives in the preparation of anti-inflammatory drugs.

[0028] Compared with the prior art, the present application provides a new class of compounds, forskolin ester derivatives, and preparation methods and applications thereof. The compound structure contains a cyclic ether structure, and this new structure gives this class of derivatives excellent anti-inflammatory activity, and can be used in the preparation of anti-inflammatory drugs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0030] Figure 1 The NMR of the forskolin ester derivative (3a) provided in Example 2 of the present invention is 1 H spectrum;

[0031] Figure 2 The NMR of the forskolin ester derivative (3a) provided in Example 2 of the present invention is 13 C spectrum;

[0032] Figure 3 The NMR of the forskolin ester derivative (3b) provided in Example 4 of the present invention is 1 H spectrum;

[0033] Figure 4 The NMR of the forskolin ester derivative (3b) provided in Example 4 of the present invention is 13 C spectrum. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Example 1

[0036] 82 mg (0.2 mmol) of forskolin, 37 mg of benzoic acid (0.3 mmol), 82 mg of dicyclohexylcarbodiimide (0.4 mmol), and 46 mg of 4-dimethylaminopyridine (0.4 mmol) were dissolved in dichloromethane (5 ml) and reacted at room temperature for 24 hours. The reaction solution was concentrated under reduced pressure, then diluted with ethyl acetate (15 ml), and then washed with water and saturated brine, and MgSO 4 The residue was dried, concentrated under reduced pressure, and purified by column chromatography (petroleum ether:ethyl acetate=2:1) ​​to obtain 87 mg of a white solid, i.e., forskolin ester intermediate 2a (yield=85%).

[0037] 1 H NMR(400MHz,Chloroform-d)δ7.99(d,J=1.2Hz,1H,Ar-H),7.97(d,J=1.6Hz,1H,Ar-H),7.60–7.54(m,1H,Ar-H),7.4 6(dd,J=8.4,7.0Hz,2H,Ar-H),5.84(s,1H,H-1),5.80(dd,J=17.2,10.7Hz,1H,H-14),5.54(d,J=4.2Hz,1H,H-7),5. 14(dd,J=17.1,1.1Hz,1H,H-15),4.84(dd,J=10.7,1.1Hz,1H,H-15),4.52(s,1H,H-6),4.50(s,1H,9-OH),3.03(d,J =16.3Hz,1H,H-15),2.41(d,J=2.7Hz,1H,H-5),2.35(d,J=16.3Hz,1H,H-15),2.30-2.20(m,1H),2.18(s,3H,7-OCOCH 3 ),1.92(s,1H,6-OH),1.74(s,3H,CH 3 ),1.72-1.69(m,1H),1.68(s,1H),1.63(s,3H,CH 3 ),1.32(s,3H,CH 3 ),1.32(s,3H,CH 3 ),1.24-1.17(m,1H),1.10(s,3H,CH 3 ).

[0038] Example 2

[0039] 102 mg (0.2 mmol) of forskolin ester intermediate 2a was dissolved in tetrahydrofuran (4 ml), and then 10 mg (0.04 mmol) of palladium acetate was added, and the mixture was reacted at 40° C. for 24 hours. The reaction solution was concentrated under reduced pressure, and column chromatography (petroleum ether: ethyl acetate = 10:1) was performed to obtain 92 mg of a white solid, i.e., forskolin ester derivative 3a (yield = 90%).

[0040] 1H NMR(400MHz,Chloroform-d)δ8.04(dd,J=8.3,1.4Hz,1H,ArH),7.59-7.50(m,1H,ArH),7.46–7.37(m,2H ArH),5.69(t,J=2.7Hz,1H,H-1),5.26(d,J=3.8Hz,1H,H-7),4.50(t,J=2.0Hz,1H,H-6),3.71(d,J=2.3Hz,1H,H-15),3.41(d,J=2.3Hz,1 H,H-15),2.53(d,J=18.7Hz,1H,H-12),2.40(d,J=18.5Hz,1H,H-12),2.39(d,J=1.9Hz,1H,H-5),2.36-2.27(m,1H),2.15(s,3H,7-OCOCH 3 ),1.99(td,J=13.8,3.7Hz,1H),1.81(s,1H,6-OH),1.74(s,3H,CH 3 ),1.63-1.57(m,1H),1.53(s,3H,CH 3 ),1.37(s,3H,CH 3 ),1.31-1.28(m,1H),1.18(s,3H,CH 3 ),1.17(s,3H,CH 3 ); 13 C NMR (100 MHz, CDCl 3 )δ201.1,169.8,165.3,158.1,132.6,131.3,129.8,128.1,86.1,82.3,80.0,75.8,73.1,6 9.9,69.6,49.3,43.8,37.3,34.7,33.3,25.1,25.0,24.3,21.2,21.0,19.4.HRMS(ESI):m / z calcd forC 29 H 36 O 8 Na:535.2308; found:535.2316[M+Na] + .

[0041] Example 3

[0042] According to the method of Example 1 above, the forskolin ester intermediate 2b was prepared by replacing the benzoic acid in Example 1 with p-chlorobenzoic acid.

[0043] 2b: yield 87%, 1H NMR(400MHz,Chloroform-d)δ8.00–7.86(m,2H,ArH),7.45–7.37(m,2H,ArH),5.83(s,1H,H-1),5. 79(dd,J=17.2,10.8Hz,1H,H-14),5.49(d,J=4.1Hz,1H,H-7),5.18(dd,J=17.1,1.1Hz,1H,H-15),4 .88(dd,J=10.7,1.1Hz,1H,H-15),4.52(s,1H,H-6),4.22(s,1H,9-OH),2.99(d,J=16.6Hz,1H,H-12 ),2.39(d,J=16.6Hz,1H,H-12),2.39(d,J=2.8Hz,1H,H-5),2.31–2.22(m,1H),2.20(s,3H,7-OCOCH 3 ),1.97(s,1H,6-OH),1.82–1.77(m,1H),1.76(s,3H,CH 3 ),1.69–1.66(m,1H),1.62(s,3H,CH 3 ),1.33(s,6H,CH 3 ,CH 3 ),1.22(m,1H),1.10(s,3H,CH 3 ). 13 C NMR (100 MHz, CDCl 3 )δ204.6,169.8,163.9,145.6,139.3,131.0,129.3,128.8,110.6,82.4,81.8,76.4,76.2,75. 6,69.8,48.4,44.0,43.4,37.2,34.4,33.2,31.1,24.5,23.8,23.5,21.2,19.7.HRMS(ESI):m / z calcd for C 29 H 37 O 8 ClNa:571.2069; found:571.2083[M+Na] + .

[0044] Example 4

[0045] According to the method of Example 2 above, forskolin ester intermediate 3b was prepared by replacing forskolin ester intermediate 2a in Example 2 with forskolin ester intermediate 2b.

[0046] 3b: yield 85%, 1H NMR(400MHz,Chloroform-d)δ8.02-7.96(m,2H,ArH),7.44-7.39(m,2H,ArH),5.69(dd,J=3 .6,2.1Hz,1H,H-1),5.27(d,J=3.8Hz,1H,H-7),4.52(t,J=3.7Hz,1H,H-6),3.78(d,J=2.4Hz ,1H,H-15),3.47(d,J=2.3Hz,1H,H-15),2.55(d,J=18.8Hz,1H,H-12),2.40(d,J=18.7Hz,1H ,H-12),2.37(d,J=2.8Hz,1H,H-5),2.32(ddd,J=14.6,3.8,2.2Hz,1H),2.17(s,3H,7-OCOCH 3 ),1.95(td,J=13.6,3.6Hz,1H),1.83(s,1H,6-OH),1.75(s,3H,CH 3 ),1.61(dt,J=14.8,3.5Hz,1H),1.54(s,3H,CH 3 ),1.38(s,3H,CH 3 ),1.34–1.31(m,1H),1.21(s,3H,CH 3 ),1.18(s,3H,CH 3 ). 13 C NMR (100 MHz, CDCl 3 )δ201.0,169.7,164.5,158.1,138.9,131.2,129.7,128.5,86.1,82.4,80.0,75.7,73.5,69.9,6 9.5,49.2,43.9,43.8,37.3,34.7,33.2,25.1,24.9,24.3,21.2,20.9,19.4.HRMS(ESI):m / zcalcd for C 29 H 35 C1O 8 Na:569.1918; found:569.1924[M+Na] + .

[0047] Example 5

[0048] According to the method of Example 1 above, forskolin ester intermediate 2c was prepared by replacing benzoic acid in Example 1 with p-toluic acid.

[0049] 2c: yield 85%, 1H NMR(400MHz,Chloroform-d)δ7.94–7.84(m,2H,ArH),7.29–7.27(m,2H,ArH),5 .84(s,1H,H-1),5.83(dd,J=17.9,9.9Hz,1H,H-14),5.58(d,J=4.2Hz,1H,H-7), 5.16(dd,J=17.1,1.2Hz,1H,H-15),4.86(dd,J=10.6,1.2Hz,1H,H-15),4.64(s ,1H,9-OH),4.54(s,1H,H-6),3.06(d,J=16.2Hz,1H,H-12),2.43(s,3H,7-OCOCH 3 ),2.42(s,1H,H-5),2.35(d,J=16.1Hz,1H,H-12),2.26(ddd,J=15.8,12.7,3.2Hz,1H),2.20(s,3H,CH 3 ),1.93(s,1H,6-OH),1.77(d,J=3.3Hz,1H),1.75(s,3H,CH 3 ),1.69(m,1H),1.64(s,3H,CH 3 ),1.34(s,3H,CH 3 ),1.33(s,3H,,CH 3 ),1.24–1.18(m,1H),1.11(s,3H,CH 3 ). 13 C NMR (100 MHz, CDCl 3 )δ201.1,169.8,165.4,158.1,143.1,129.8,128.8,128.6,86.0,82.3,80.0,75.9,72.9,69.9,6 9.6,49.3,43.8,43.8,37.3,34.7,33.3,25.1,24.9,24.3,21.7,21.2,21.0,19.4.HRMS(ESI):m / z calcd for C 30 H 40 O 8 Na:551.2615; found:551.2628[M+Na] + .

[0050] Example 6

[0051] According to the method of Example 2 above, forskolin ester intermediate 3c was prepared by replacing forskolin ester intermediate 2a in Example 2 with forskolin ester intermediate 2c.

[0052] 3c: Yield 87%, 1 H NMR (400 MHz, Chloroform-d) δ 7.94 (d, J = 8.1 Hz, 2H, ArH), 7.23 (d, J = 8.0 Hz, 2H, ArH), 5.68 (dd, J = 3.6, 2.0 Hz, 1H, H-1), 5.28 (d, J = 3.9 Hz, 1H, H-7), 4.52 (t, J = 3.4 Hz, 1H, H-6), 3.74 (d, J = 2.2 Hz, 1H, H-15), 3.49 (d, J = 2.3 Hz, 1H, H-15), 2.53 (d, J = 18.7 Hz, 1H, H-12), 2.41 (s, 3H, 7-OCOCH 3 ), 2.41 (d, J = 18.6 Hz, 1H, H-12), 2.40 (d, J = 3.1 Hz, 1H, H-5), 2.32 (tdd, J = 14.4, 3.8, 2.2 Hz, 1H), 2.16 (s, 3H, CH 3 ), 1.98 (td, J = 13.7, 3.8 Hz, 1H), 1.88 (s, 1H, CH 3 ), 1.75 (s, 3H, CH 3 ), 1.61 (dq, J = 14.3, 3.5 Hz, 1H), 1.54 (s, 3H, CH 3 ), 1.38 (s, 3H, CH 3 ), 1.32–1.28 (m, 1H), 1.20 (s, 3H, CH 3 ), 1.18 (s, 3H, CH 3 ). 13 C NMR (101 MHz, CDCl 3 ) δ 201.1, 169.8, 165.4, 158.1, 143.1, 129.8, 128.8, 128.6, 86.0, 82.3, 80.0, 75.9, 72.9, 69.9, 69.6, 49.3, 43.8, 43.8, 37.3, 34.7, 33.3, 25.1, 24.9, 24.3, 21.7, 21.2, 21.0, 19.4. HRMS (ESI): m / z calcd for C 30 H 38 O 8 Na: 549.2464; found: 549.2462 [M+Na] + .

[0053] Example 7

[0054] According to the method of Example 1 above, phenylacetic acid was used instead of benzoic acid in Example 1 to prepare forskolin ester intermediate 2d.

[0055] 2d: yield 87%, 1 H NMR(400MHz,Chloroform-d)δ7.35–7.21(m,5H,Ar-H),5.82(dd,J=17.1,10.6Hz,1H,H-14),5.56–5. 50(m,1H,H-1),5.47(d,J=4.2Hz,1H,H-7),5.20(dd,J=17.1,1.2Hz,1H,H-15),4.95(dd,J=10.6,1.2 Hz,1H,H-15),4.45(d,J=3.5Hz,1H,H-6),4.32(s,1H,9-OH),3.61(d,J=14.6Hz,1H,ArCH),3.54(d,J =14.6Hz,1H,ArCH),2.76(d,J=16.2Hz,1H,H-12),2.22(d,J=16.3Hz,1H,H-12),2.18(s,3H,7-OCOCH 3 ),2.16(d,J=2.9Hz,1H,H-5),2.11(dt,J=14.8,3.3Hz,1H),1.87(s,1H,6-OH),1.66(s,3H,CH 3 ),1.61(dq,J=15.5,3.4Hz,1H),1.53(s,3H,CH 3 ),1.41(td,J=14.1,3.7Hz,1H),1.30(s,3H,CH 3 ),1.26(s,3H,CH 3 ),1.09(dt,J=13.4,3.5Hz,1H),1.02(s,3H,CH 3 ). 13 C NMR (100 MHz, CDCl 3 )δ205.5,169.7,169.1,145.9,133.3,129.1,128.8,127.4,110.3,81.9,81.7,76.5,75.6,69. 6,48.6,43.8,43.2,42.3,36.7,34.1,32.9,30.9,24.2,23.8,23.1,21.2,19.8.HRMS(ESI):m / z calcd for C 30 H 40 O 8Na:551.2615; found:551.2622[M+Na] + .

[0056] Example 8

[0057] According to the method of Example 2 above, forskolin ester intermediate 3d was prepared by replacing forskolin ester intermediate 2a in Example 2 with forskolin ester intermediate 2d.

[0058] 3d: yield 92%, 1 H NMR(400MHz,Chloroform-d)δ7.34-7.25(m,5H,ArH),5.41(d,J=2.8Hz,1H,H-1),5.32(d,J =3.9Hz,1H,H-7),4.48(dt,J=4.3,2.4Hz,1H,H-6),4.41(d,J=2.3Hz,1H,H-15),4.18(d,J=2 .3Hz,1H,H-15),3.64(d,J=15.1Hz,1H,ArCH),3.53(d,J=15.1Hz,1H,ArCH),2.56(d,J=18.7 Hz,1H,H-12),2.42(d,J=18.7Hz,1H,H-12),2.26(d,J=2.8Hz,1H,H-5),2.18(s,3H,7-OCOCH 3 ),2.16-2.06(m,1H),1.87(s,1H,6-OH),1.67(s,3H,CH 3 ),1.59(td,J=14.1,4.0Hz,1H),1.53(S,3H,CH 3 ),1.40-1.36(m,1H),1.36-1.33(m,1H),1.32(s,3H,CH 3 ),1.30(s,3H,CH 3 ),1.07(s,3H,CH 3 ). 13 C NMR (100 MHz, CDCl 3 )δ200.8,170.5,169.8,158.9,134.5,129.4,128.4,126.8,86.1,82.3,80.2,75.8,73.4,70.1,6 9.5,49.1,43.6,41.9,36.6,34.5,32.9,25.0,24.6,24.3,21.2,21.0,19.3.HRMS(ESI):m / zcalcd for C 30 H 38 O8 Na:549.2464; found:549.2471[M+Na] + .

[0059] In order to better understand the essence of the present invention, the pharmacological experimental results of the inhibitory effect of the forskolin ester derivatives provided by the present invention on the NO release of RAW264.7 cells induced by LPS are used below to illustrate its new use in the field of anti-tumor drug research. The pharmacological examples give some activity data of representative compounds. It must be noted that the pharmacological examples of the present invention are used to illustrate the present invention rather than to limit the present invention. Simple improvements made to the present invention according to the essence of the present invention all belong to the scope of protection claimed in the present invention.

[0060] Drug Example 1: Inhibitory activity of compounds 3a-3d and dexamethasone on LPS-induced NO release in RAW 264.7 macrophages

[0061] RAW264.7 macrophages were cultured at 1×10 5 The cells were seeded at a density of 100 / mL in a 96-well plate and incubated at 37°C and 5% CO 2 Incubate in the incubator for 24 hours. This experiment set up a control group, an LPS-induced group, a positive control dexamethasone (DEX) group and an experimental group. The positive control group and the experimental group added 0.2, 1.0, 5.0, and 25.0 μM of the test compound 3a-3d or DEX to the treated RAW264.7 macrophages. After 4 hours, 10 μL of culture medium was added to the control group, and LPS (1.0 μg / mL) was added to the other groups to induce the cells. The cells were incubated for 24 hours, centrifuged, and the supernatant of the cells was collected. The release of NO was determined by a nitric oxide kit, and the IC was calculated using Graphpad5 software. 50 The MTT method was used to detect the effects of the compounds at 20 μM on the growth of RAW264.7 macrophages.

[0062] Table 1 Inhibitory activity of compounds 3a-3d and dexamethasone on LPS-induced NO release in RAW 264.7 macrophages

[0063] Compound <![CDATA[IC 50 / (μM)]]> Cell survival rate / % 3a 1.9 99.96±2.11 3b 17.1 99.55±3.12 3c 2.9 100.11±4.02 3d 0.5 99.86±3.21 DEX 34.2 98.27±4.53

[0064] As shown in Table 1, the forskolin ester derivatives provided by the present invention have important biological activities. The inhibitory activity test of LPS-induced RAW 264.7 macrophage NO release shows that the forskolin ester derivatives of the structure shown in formula (1) have good inhibitory activity on LPS-induced RAW264.7 macrophage NO release. The inhibitory effects of compounds 3a-3d in the examples are significantly better than those of the positive control drug dexamethasone, and there is no obvious cytotoxicity, so they may be developed into new anti-inflammatory drugs.

[0065] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. Use of a forskolin ester derivative in the preparation of anti-inflammatory drugs; The structure of the forskolin ester derivative is shown in the following formula: in, R represents one of phenyl, p-chlorophenyl, p-methylphenyl, p-bromophenyl, p-fluorophenyl and benzyl.

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