阅读说明：本技术 一种二苯乙烷类化合物的制备方法 (Preparation method of diphenylethane compound ) 是由 吴范宏 李玉洁 黄金文 刘运立 夏郅 聂辉 李中原 唐慧 于 2020-11-05 设计创作，主要内容包括：本发明涉及一种二苯乙烷类化合物的制备方法,包括以下步骤：(1)将3,4,5-三甲氧基苯乙酸和3-羟基-4-烷氧基苯甲醛溶于有机溶剂中,加入有机碱,经Perkin反应制得二苯基乙烯酸中间体；(2)将二苯乙烯酸中间体溶于有机溶剂中,加入叠氮磷酸二苯酯和有机碱,经Curtis重排反应制得N-叔丁氧酰二苯乙烯胺中间体；(3)将N-叔丁氧酰二苯乙烯胺中间体用强酸脱保护和水解,制得酮中间体；(4)将酮中间体溶于有机溶剂中,加入水合肼和氢氧化钾,经Wolff-Kishner-黄鸣龙还原反应,制得具有如下结构的二苯乙烷类化合物：其中,R为甲基或乙基。与现有技术相比,本发明具有反应条件温和,合成难度低,后处理较简单,储存条件温和,合成过程较为安全等优点。(The invention relates to a preparation method of diphenylethane compounds, which comprises the following steps: (1) 3,4, 5-trimethoxy phenylacetic acid and 3-hydroxy-4-Dissolving alkoxy benzaldehyde in an organic solvent, adding organic base, and performing Perkin reaction to obtain a diphenylethylene acid intermediate; (2) dissolving the stilbene acid intermediate in an organic solvent, adding diphenyl phosphorazide and organic base, and carrying out Curtis rearrangement reaction to obtain an N-tert-butoxy acyl stilbene amine intermediate; (3) deprotecting and hydrolyzing the N-tert-butoxy acyl stilbene amine intermediate by strong acid to prepare a ketone intermediate; (4) dissolving the ketone intermediate in an organic solvent, adding hydrazine hydrate and potassium hydroxide, and carrying out Wolff-Kishner-Huang Minlon reduction reaction to obtain a diphenylethane compound with the following structure: wherein R is methyl or ethyl. Compared with the prior art, the method has the advantages of mild reaction conditions, low synthesis difficulty, simpler post-treatment, mild storage conditions, safer synthesis process and the like.)

1. A preparation method of diphenylethane compounds is characterized by comprising the following steps:

(1) dissolving 3,4, 5-trimethoxy phenylacetic acid and 3-hydroxy-4-alkoxy benzaldehyde in an organic solvent, adding organic base, and performing Perkin reaction to obtain a diphenylethylene acid intermediate;

(2) dissolving the stilbene acid intermediate in an organic solvent, adding diphenyl phosphorazide and organic base, and carrying out Curtis rearrangement reaction to obtain an N-tert-butoxy acyl stilbene amine intermediate;

(3) deprotecting and hydrolyzing the N-tert-butoxy acyl stilbene amine intermediate by strong acid to prepare a ketone intermediate;

(4) dissolving the ketone intermediate in an organic solvent, adding hydrazine hydrate and potassium hydroxide, and carrying out Wolff-Kishner-Huang Minlon reduction reaction to obtain the diphenylethane compound.

2. A process for the preparation of diphenylethane compounds according to claim 1 wherein said diphenylethane compounds have the structure shown below:

wherein R is methyl or ethyl;

the 3-hydroxy-4-alkoxy benzaldehyde is 3-hydroxy-4-methoxy benzaldehyde or 3-hydroxy-4-ethoxy benzaldehyde.

3. The method for preparing diphenylethane compounds according to claim 1, wherein the organic solvent in step (1) is acetic anhydride, and the organic base is triethylamine or diisopropylethylamine.

4. A method for producing a diphenylethane compound according to claim 1 or 3, wherein the molar ratio of the 3,4, 5-trimethoxyphenylacetic acid, the 3-hydroxy-4-alkoxybenzaldehyde and the organic base in step (1) is 1:1: 1.5-2.0.

5. The method for preparing diphenylethane compounds according to claim 1 or 3, wherein the reaction temperature in step (1) is 90-130 ℃ and the reaction time is 6-8 h.

6. The method for preparing diphenylethane compounds according to claim 1, wherein the organic solvent in step (2) is t-butanol, and the organic base is triethylamine.

7. The method for preparing diphenylethane compounds according to claim 1 or 6, wherein the molar ratio of the diphenylethylene acid intermediate in step (2), the diphenyl phosphorazidate and the organic base is 1: 1.1-2.0.

8. The method for preparing diphenylethane compounds according to claim 1 or 6, wherein the reaction temperature in step (2) is 80-100 ℃ and the reaction time is 15-18 h.

9. The method for preparing diphenylethane compounds according to claim 1, wherein the acid used for the deprotection in step (3) is 4-12M hydrochloric acid, an alcohol solution of hydrochloric acid, or a dichloromethane solution of trifluoroacetic acid or trifluoroacetic acid.

10. The preparation method of the diphenylethane compounds according to claim 1, wherein the organic solvent in the step (4) is ethylene glycol or diethylene glycol, the molar ratio of the ketone intermediate, hydrazine hydrate and potassium hydroxide is 1: 2-3: 3, the reaction temperature is 120-200 ℃, and the reaction time is 4-8 h.

Technical Field

The invention relates to the technical field of medicinal chemistry, in particular to a preparation method of diphenylethane compounds.

Background

Erianin, whose chemical name is 3,4, 5-trimethoxy-3 '-hydroxy-4' -methoxy diphenylethane (code: MLS), is a natural diphenylethane active component extracted from noble Chinese medicinal material dendrobium and has anti-tumor effect. The erianin structurally has the same structural characteristics with the toluastatin A-4 (code number CA4, also called windmill element) which is a natural product of stilbenes, has a common AB ring structure, and is equivalent to CA4 with a hydrogenated vinyl bridge. Like CA4, erianin is a tubulin inhibitor and has strong tumor blood vessel targeted disruption effect, acting on colchicine binding site. In addition, the literature reports that the antitumor effect of erianin is possibly related to the induction of tumor cell apoptosis through the action of inhibiting VEGF expression and telomerase, and the erianin also has the anticancer effect on liver cancer, melanoma, non-small cell lung cancer, myeloid leukemia, breast cancer and osteosarcoma. The ethoxy erianin (code number EBT, Ib) is a structural modifier substituted by the 4 th ethoxy group of the ring of erianin B, has the same action mechanism as erianin, obviously enhances the anti-tumor activity under the same condition, and shows good application and development prospects.

The synthesis literature of erianin mostly synthesizes olefin by using Wittig reaction, the Wittig reaction is a very efficient method for preparing olefin by reducing double bonds through Pd/C, but the reaction conditions are harsh, ylide reagents are sensitive to water and oxygen, phenolic hydroxyl groups in aldehyde raw materials are usually protected by benzyl, inert gas is required for protection in the reaction process, water and air need to be isolated in the synthesis process, and in addition, the problem of heavy metal residue can be caused by using palladium-carbon to dehydrogenate benzyl. Therefore, there is a need to develop a new green and efficient process for synthesizing erianin and derivatives thereof.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide a preparation method of a diphenylethane compound, which has the advantages of mild reaction conditions, no need of anhydrous and anaerobic operation treatment, avoidance of heavy metal residue caused by palladium-carbon, low synthesis difficulty, simple post-treatment, mild storage conditions and safer synthesis process.

The purpose of the invention can be realized by the following technical scheme: a preparation method of diphenylethane compounds comprises the following steps:

(1) dissolving 3,4, 5-trimethoxy phenylacetic acid and 3-hydroxy-4-alkoxy benzaldehyde in an organic solvent, adding organic base, and performing Perkin reaction to obtain a diphenylethylene acid intermediate;

(2) dissolving a stilbene acid intermediate in an organic solvent, adding diphenyl phosphorazide (DPPA) and an organic base, and carrying out Curtis rearrangement reaction to obtain an N-tert-butoxy acyl stilbene amine intermediate;

(3) deprotecting and hydrolyzing the N-tert-butoxy acyl stilbene amine intermediate by strong acid to prepare a ketone intermediate;

(4) dissolving the ketone intermediate in an organic solvent, adding hydrazine hydrate and potassium hydroxide, and carrying out Wolff-Kishner-Huang Minlon reduction reaction to obtain the diphenylethane compound.

The diphenylethane compound has the following structure:

wherein R is methyl or ethyl.

The 3-hydroxy-4-alkoxy benzaldehyde is 3-hydroxy-4-methoxy benzaldehyde or 3-hydroxy-4-ethoxy benzaldehyde.

Further, the organic solvent in the step (1) is acetic anhydride, and the organic base is triethylamine or diisopropylethylamine.

The molar ratio of the 3,4, 5-trimethoxyphenylacetic acid, the 3-hydroxy-4-alkoxybenzaldehyde and the organic base in the step (1) is 1:1: 1.5-2.0, the reaction temperature is 90-130 ℃, and the reaction time is 6-8 h.

The organic solvent in the step (2) is tert-butyl alcohol, the organic base is triethylamine, the molar ratio of the stilbene acid intermediate to the diphenyl azidophosphate to the organic base is 1: 1.1-2.0, the reaction temperature is 80-100 ℃, and the reaction time is 15-18 hours.

And (3) the acid used for the deprotection operation in the step (3) is 4-12M hydrochloric acid, an alcohol solution of hydrochloric acid, trifluoroacetic acid or a dichloromethane solution of trifluoroacetic acid, and preferably 6M hydrochloric acid.

The organic solvent in the step (4) is ethylene glycol or diethylene glycol, the molar ratio of the ketone intermediate to hydrazine hydrate to potassium hydroxide is 1: 2-3: 3, the reaction temperature is 120-200 ℃, and the reaction time is 4-8 hours.

The 3,4, 5-trimethoxyphenylacetic acid and 3-hydroxy-4-methoxybenzaldehyde are commercial reagents purchased from Shanghai Tantan chemical Co., Ltd, and the 3-hydroxy-4-ethoxybenzaldehyde is synthesized by referring to Chinese patent CN 107382796.

The invention adopts easily available 3,4, 5-trimethoxyphenylacetic acid and 3-hydroxy-4-methoxybenzaldehyde or 3-hydroxy-4-ethoxybenzaldehyde as raw materials, and prepares the erianin and 4-ethoxy substituted derivatives thereof through 4-step reaction, the reaction conditions are mild, the reaction does not need anhydrous and anaerobic operation treatment, the post-treatment process is relatively simple, the phenolic hydroxyl in the aldehyde raw materials used in the process does not need benzyl protection operation, the heavy metal residue problem caused by the use of palladium carbon for debenzylation is avoided, and the invention has the characteristics of low synthesis cost, small synthesis difficulty, simpler post-treatment, mild storage conditions and safer synthesis process.

Compared with the prior art, the invention has the following advantages: the method has the advantages of cheap and easily-obtained raw material reagents, mild reaction conditions, simple experimental operation and good stability of each intermediate product, avoids using organophosphorus and palladium carbon catalysts, has no triphenoxy phosphorus by-product and no heavy metal residue compared with the wittig reaction process, and is more suitable for industrial production.

Drawings

FIG. 1 is a schematic diagram of the synthetic routes of examples 1 to 6;

FIG. 2 is a NMR spectrum of the product of example 1;

FIG. 3 is a NMR spectrum of the product of example 2;

FIG. 4 is a NMR spectrum of the product of example 3;

FIG. 5 is a NMR spectrum of the product of example 4;

FIG. 6 is a NMR spectrum of the product of example 5;

FIG. 7 is a NMR spectrum of the product of example 6.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments. The following examples are carried out on the premise of the technical scheme of the invention, and detailed embodiments and specific operation processes are given, but the scope of the invention is not limited to the following examples.

Example 1

(E) Preparation of 3- (3-hydroxy-4-methoxyphenyl) -2- (3,4, 5-trimethoxyphenyl) acrylic acid (3 a):

putting 3,4, 5-trimethoxyphenylacetic acid (50.0g) and 3-hydroxy-4-methoxybenzaldehyde (33.6g) into a 500mL round-bottom flask, adding 200mL acetic anhydride, stirring to dissolve, dropwise adding 33.5g triethylamine, and heating to 100 ℃ to react for 6-8 h. And (3) cooling the TLC spot plate to room temperature after complete reaction, pouring the reaction liquid into ice water, adjusting the pH value to 1-2 by using 1M hydrochloric acid, stirring for 4 hours to obtain an orange solid, and performing suction filtration. Dissolving the filter cake in 10% NaOH aqueous solution, extracting with ethyl acetate for 3 times (discarding), adjusting pH of the aqueous phase to 1-2 with 1M hydrochloric acid to obtain light yellow solid, filtering, washing with water, and drying to obtain 62.5g of light yellow solid with yield of 78.5%.¹H NMR(500MHz,DMSO-d₆)δ7.56(s,1H),6.78(d,J＝5.0Hz,1H),6.60–6.56(m,2H),6.44(s,2H),3.72(d,J＝5.0Hz,6H),3.68(s,6H).¹³C NMR(125MHz,DMSO-d₆)δ169.15,153.14,153.14,148.79,146.02,138.36,137.02,132.79,131.70,127.50,122.79,122.79,117.32,111.64,106.94,60.26,56.03,56.03,55.58。

Example 2

(E) Preparation of 3- (3-hydroxy-4-ethoxyphenyl) -2- (3,4, 5-trimethoxyphenyl) acrylic acid (3 b):

3,4, 5-trimethoxyphenylacetic acid (50.0g) and 3-hydroxy-4-ethoxybenzaldehyde (36.7g) were placed in a 500mL round-bottomed flask, 200mL of acetic anhydride was added, and stirred to dissolve, 57.1g of diisopropylethylamine was added dropwise, and the mixture was reacted at 100 ℃ for 6 to 8 hours. After the TLC plate reaction is completed, the plate is cooled to room temperature. Pouring the reaction solution into ice water, adjusting the pH value to 1-2 by using 1M hydrochloric acid, separating out orange yellow solid, and performing suction filtration. Dissolving the filter cake in 10% NaOH aqueous solution, extracting with ethyl acetate for 3 times, discarding the organic phase, adjusting pH of the water phase to 1-2 with 1M hydrochloric acid to precipitate pale yellow solid, filtering, washing with water, and drying to obtain 73.4g of pale yellow solid with a yield of 88.8%.¹H NMR(500MHz,CDCl₃)δ7.66(s,1H),7.32(s,1H),7.03(s,1H),6.89(s,1H),6.87(d,J＝10.0Hz,2H),4.10(q,J＝5.0Hz,2H),3.90(s,6H),3.83(s,3H),1.42(t,J＝5.0Hz,3H).¹³C NMR(125MHz,CDCl₃)δ167.12,153.56,153.56,149.68,149.26,149.13,139.52,136.68,131.45,130.02,128.65,128.65,128.59,128.28,127.94,127.94,122.19,114.35,113.77,108.40,108.40,70.07,65.62,62.82,56.49,56.49,14.55。

Example 3

Synthesis of 2- (3-hydroxy-4-methoxyphenyl) -1- (3,4, 5-trimethoxyphenyl) ethan-1-one (5 a):

50.0g of the product obtained in example 1 was placed in a 500mL round-bottom flask, and 200mL of t-butanol, triethylamine (14.9g) and diphenylphosphorylazide (40.4g) were added to the flask with a stirrer, and the mixture was stirred well and heated under reflux for 15 to 18 hours. And (3) cooling the TLC spot plate to room temperature after complete reaction, adding water, stirring for 10min, separating liquid, washing with water, and performing reduced pressure rotary evaporation on an organic phase to recover tert-butyl alcohol.

Dissolving the residual liquid in ethanol, adding 6M hydrochloric acid, stirring for 1h to precipitate solid, filtering, washing with methanol water (1/1), and drying to obtain 43.5g solid with yield of 94.0%.¹H NMR(500MHz,CDCl₃)δ7.62-7.59(m,2H),6.90(d,J＝10.0Hz,2H),6.47(s,2H),4.16(s,3H),3.96(s,3H),3.84(s,6H),3.82(s,3H).¹³C NMR(125MHz,CDCl₃)δ197.16,153.47,153.47,149.27,148.77,143.06,137.76,132.18,128.91,128.91,128.21,127.90,127.75,127.75,122.79,116.59,114.57,106.77,106.77,71.83,65.19,61.41,56.73,56.73,45.61,15.44。

Example 4

Preparation of 2- (3-hydroxy-4-ethoxyphenyl) -1- (3,4, 5-trimethoxyphenyl) ethan-1-one (5 b):

50.0g of the product obtained in example 2 was placed in a 500mL round-bottom flask, and 200mL of t-butanol, triethylamine (14.9g) and diphenylphosphorylazide (40.4g) were added to the flask with a stirrer, and the mixture was stirred well and heated under reflux for 15 to 18 hours. And (3) cooling the TLC spot plate to room temperature after complete reaction, adding water, stirring for 10min, separating liquid, washing with water, and performing reduced pressure rotary evaporation on an organic phase to recover tert-butyl alcohol.

Dissolving the residual liquid in ethanol, adding 6M hydrochloric acid, stirring for 1h,a solid precipitated, and was filtered, washed with methanol water (1/1), and dried to obtain 43.5g of a solid with a yield of 94.0%.¹H NMR(500MHz,CDCl₃)δ6.80(d,J＝5.0,1H),6.74(d,J＝10.0,1H),6.62–6.60(m,2H),6.50(s,2H),4.06(q,J＝5.0,3H),3.83(s,3H),3.81(s,6H),1.40(t,J＝7.5Hz,3H).¹³C NMR(125MHz,CDCl₃)δ197.16,153.47,153.47,149.27,148.77,143.06,137.76,132.18,128.91,128.91,128.21,127.90,127.75,127.75,122.79,116.59,114.57,106.77,106.77,71.83,65.19,61.41,56.73,56.73,45.61,15.44。

Example 5

Synthesis of 3,4, 5-trimethoxy-3 '-hydroxy-4' -methoxydiphenylethane (Ia, i.e. erianin):

40g of the ketone intermediate obtained in example 3 was placed in a 250mL round-bottom flask, and 20mL of ethylene glycol, 12g of hydrazine hydrate, and 20.2g of potassium hydroxide were sequentially added with a stirrer. Heating to 120 ℃ for reaction for 2h, then heating to slowly evaporate excessive hydrazine hydrate, heating the reaction solution to 180 ℃ for heat preservation reaction for 5h, detecting by TLC (thin layer chromatography), cooling to room temperature, pouring the reaction solution into ice water, adjusting the pH to 3-5 with hydrochloric acid, separating out solids, filtering, and recrystallizing the solids with methanol to obtain white solids, wherein the yield is 85%, and 32.6 g.¹H NMR(500MHz,CDCl₃)δ6.81(s,1H),6.77(d,J＝20.0Hz,1H),6.64(dd,J＝0,10.0Hz,1H),6.38(s,2H),5.58(s,1H),3.87(s,3H),3.83(s,9H),2.82(s,4H).¹³C NMR(125MHz,CDCl₃)δ153.10,153.10,147.29,146.35,136.60,136.41,135.09,122.09,115.68,111.80,105.81,105.81,60.81,56.22,56.13,56.13,37.39,36.83。

Example 6

Synthesis of 3,4, 5-trimethoxy-3 '-hydroxy-4' -ethoxy diphenylethane (Ib)

40g of the product obtained in example 4 are placed in a 250mL round-bottom flask, a stirrer is added, and 200mL of ethylene glycol solution, 17.3g of hydrazine hydrate and 19.4g of potassium hydroxide are added in sequence. Heating to 120 ℃ for reaction for 2h, then heating to slowly evaporate excessive hydrazine hydrate, keeping the temperature after the temperature of the reaction mixture reaches 200 ℃, reacting for about 3h, detecting by TLC, cooling to room temperature, pouring the reaction liquid into ice water, adjusting the pH to 3-5 by hydrochloric acid,solid was precipitated, filtered and the solid was recrystallized from ethanol to give a white solid with a yield of 34.5g of 90%.¹H NMR(500MHz,CDCl₃)δ6.81(s,J＝2.1Hz,1H),6.75(d,J＝10.0Hz,1H),6.62(d,J＝10.0Hz,1H),6.38(s,2H),5.66(s,1H),4.09(q,J＝5.0Hz,2H),3.83(s,9H),2.82(s,4H),1.43(t,J＝7.5Hz,3H).¹³C NMR(125MHz,CDCl₃)δ153.5(x2),146.2,144.6，138.1,136.6,135.4,120.3,115.1,112.1,105.9(x2),65.1,61.4,56.5(x2),38.9,37.8,15.4。

The synthetic routes described in examples 1-6 are shown in FIG. 1.

The embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.