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Method for preparing 3,4,5-trimethoxyphenol

A technology for trimethoxyphenol and trimethoxybenzamide is applied in the field of preparation of pharmaceutical intermediates 3, can solve the problems of difficulty in obtaining, high price, low product yield and the like, and achieves simple and practical operation, safe use, high yield and the like. high effect

Inactive Publication Date: 2011-03-23
KPC PHARM INC +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The process conditions of this method are harsh, the reagents used in the reaction are flammable and explosive, expensive and difficult to obtain or cannot be prepared in large quantities, the product yield is also very low, less than 50%, and has no industrial application value
However, it is the main disadvantage that a large amount of waste acid and iron sludge residues remaining in the nitrification and reduction reactions are not easy to handle.

Method used

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  • Method for preparing 3,4,5-trimethoxyphenol
  • Method for preparing 3,4,5-trimethoxyphenol

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Step 1: Synthesis of 3,4,5-trimethoxybenzamide

[0041] Weigh 106g (0.5mol) of 3,4,5-trimethoxybenzoic acid and place it in a 1000ml reaction flask, add 150ml of dichloromethane and 6 drops of DMF, add SOCl 2A total of about 45ml. Then stirred and heated to 30° C. for reflux reaction for 5 hours. Let cool, and try to remove all solvent and unreacted SOCl by distillation under reduced pressure 2 , add 200ml of acetone to dissolve the residual solid (i.e. acid chloride) and then slowly add dropwise to 500ml of 25% concentrated ammonia water at 0°C for about 30min while vigorously stirring. After dropping, continue to stir for 20 minutes, filter, collect the precipitate, wash with a small amount of cold water, press dry, and dry at 80°C to obtain a white powdery solid, namely 3,4,5-trimethoxybenzamide. Melting point: 172-175°C, weighing: 98.5g, yield: 93%. 1 HNMR (CDCl 3 ): δ7.06(s, 2H), δ3.92(s, 6H), δ3.91(s, 3H).

[0042] Step 2: Synthesis of 3,4,5-trimethoxyanilin...

Embodiment 2

[0049] Step 1: Synthesis of 3,4,5-trimethoxybenzamide

[0050] Weigh 159g (0.75mol) of 3,4,5-trimethoxybenzoic acid into a 1000ml reaction bottle, add 150ml of dichloromethane and 6ml of pyridine, and add phosphorus oxychloride to a total of about 45ml. Then stirred and heated to 80° C. for reflux reaction for 5 hours. Let cool, remove all solvents and unreacted phosphorus oxychloride by distillation under reduced pressure as much as possible, add 200ml acetone to dissolve the residual solid (i.e. acid chloride), then slowly add dropwise to 500ml 20% concentrated ammonia water at 10°C, drop it in about 30 minutes, and vigorously Stir. After dropping, continue to stir for 20 minutes, filter, collect the precipitate, wash with a small amount of cold water, press dry, and dry at 80°C to obtain a white powdery solid, namely 3,4,5-trimethoxybenzamide. Melting point: 172-175°C, weighing: 143.1 g, yield: 90%. 1 HNMR (CDCl 3 ): δ7.06(s, 2H), δ3.92(s, 6H), δ3.91(s, 3H).

[0051] S...

Embodiment 3

[0058] Step 1: Synthesis of 3,4,5-trimethoxybenzamide

[0059] Weigh 106g (0.5mol) of 3,4,5-trimethoxybenzoic acid into a 1000ml reaction bottle, add 150ml of dichloromethane and 6 drops of DMF, and add phosphorus pentachloride to a total of about 45ml. Then stirred and heated to 50° C. for reflux reaction for 5 hours. Let cool, remove all solvents and unreacted phosphorus pentachloride as much as possible by distillation under reduced pressure, add 200ml acetone to dissolve the residual solid (acyl chloride) and slowly add 500ml 30% concentrated ammonia water at 5°C dropwise for about 30 minutes. Stir. After dropping, continue to stir for 20 minutes, filter, collect the precipitate, wash with a small amount of cold water, press dry, and dry at 80°C to obtain a white powdery solid, namely 3,4,5-trimethoxybenzamide. Melting point: 172-175°C, weighing: 100.7g, yield: 95%. 1 HNMR (CDCl 3 ): δ7.06(s, 2H), δ3.92(s, 6H), δ3.91(s, 3H).

[0060] Step 2: Synthesis of 3,4,5-trimeth...

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Abstract

The invention discloses a method for preparing 3,4,5-trimethoxyphenol, relating to the field of organic synthesis. In the method, with 3,4,5-trimethoxybenzoic acid as a starting material, the 3,4,5-trimethoxyphenol is prepared by the processes of halogenation, ammonolysis, Hoffman rearrangement, diazotization and hydrolysis reaction, and the yield reach up to at least 60 percent. The method for preparing 3,4,5-trimethoxyphenol has rich raw material source, simple process, low cost and has wide industrial application prospect.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a method for preparing a pharmaceutical intermediate 3,4,5-trimethoxyphenol. Background technique: [0002] 3,4,5-Trimethoxyphenol is an important intermediate in the synthesis of natural medicines such as scutellarin and baicalein, and there is a large demand for 3,4,5-trimethoxyphenol in the industrial preparation of medicines and related drug research , many scholars have conducted research on its synthesis method, and related literature can be found in: [0003] 1. Huang. Wen-Hsin, Yang. Ching-Huey, Chien. Pei-Yu, et al., Chinese Pharmaceutical Journal (Taipei, Taiwan) 2002, 55(2), 102-107. [0004] 2. Liao. Hua-Lin, Hu. Ming-Kuan. Chemical & Pharmaceutical Bulletin. 2004, 52(10), 1162-1165. [0005] 3. Kim. Sanghee, Sohn. Dae-Won, Kim. Youn-Chul, et al., Archives of Pharmaceutical Research, 2007, 30(1), 18-21. [0006] 4. Parmar. Virinders, Gupta. Suman, Bisht. Kirpals, e...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C43/23C07C41/26
Inventor 杨健陈铎之杨兆祥普俊学杨波张伟
Owner KPC PHARM INC
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