High-purity 5-ethyl-5-(1-methylbutyl)barbituric acid preparation method

A technology of methyl butyl and barbituric acid, applied in the direction of organic chemistry, can solve the problems of affecting product purity, incomplete reaction, and poor product appearance, and achieve the effects of solvent recycling, low production cost, and less waste.

Inactive Publication Date: 2019-09-20
SHANDONG XINHUA PHARMA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, its proportioning urea and sodium alkoxide consumption is not enough, also is to cause incomplete reaction, therefore has had a strong impact on product purity, and by-product is many, and yield is lower, and complex operation, reaction time is long, and energy consumption is high, and gained product appearance is poor, needs A large amount of activated carbon decolorizes, there are many three wastes, and the cost is high

Method used

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  • High-purity 5-ethyl-5-(1-methylbutyl)barbituric acid preparation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] Step A: Add 700g of 2-pentanol and 18g of anhydrous sodium carbonate into a 2000L reaction bottle, stir and cool down to -10°C ~ -15°C, and slowly add 200g of phosphorus tribromide dropwise at a controlled temperature of -10±5°C. It takes about 2 hours to drip. It takes about 3 hours to control the reaction temperature from -10°C to room temperature under stirring, then gradually increase the temperature and distill until the internal temperature does not exceed 150°C, then stop the distillation. Evaporate the alkanol and dry it with anhydrous sodium sulfate, then add 20g of anhydrous sodium carbonate and stir for 5-10 minutes (the pH value of the alkanol solution should be neutral at this time), filter immediately, and the filtrate is subjected to atmospheric pressure fractionation, and the collection column The fraction with a top temperature of 110-113°C yielded 793.84 g of a mixture of 2-bromopentane and 2-pentanol. The content of 2-bromopentane was 33.74%.

[002...

Embodiment 2

[0026] Step A: Add 700g of 2-pentanol and 14g of anhydrous sodium carbonate into a 2000L reaction bottle, stir and cool down to -10°C ~ -15°C, and slowly add 175g of phosphorus tribromide dropwise at a temperature of -10±5°C. It takes about 2 hours to drip. It takes about 3 hours to control the reaction temperature from -10°C to room temperature under stirring, then gradually increase the temperature and distill until the internal temperature does not exceed 150°C, then stop the distillation. Evaporate the alkanol and dry it with anhydrous sodium sulfate, then add 20g of anhydrous sodium carbonate and stir for 5-10 minutes (the pH value of the alkanol solution should be neutral at this time), filter immediately, and the filtrate is subjected to normal pressure fractionation, and the collection column The fraction with a top temperature of 110-113°C yielded 756.65 g of a mixture of 2-bromopentane and 2-pentanol. The content of 2-bromopentane was 30.67%.

[0027] Step B: Add 3...

Embodiment 3

[0030] Step A: Add 700g of 2-pentanol and 42g of anhydrous sodium carbonate into a 2000L reaction bottle, stir and cool down to -10°C ~ -15°C, and slowly add 210g of phosphorus tribromide dropwise at a temperature of -10±5°C. It takes about 2 hours to drip. It takes about 3 hours to control the reaction temperature from -10°C to room temperature under stirring, then gradually increase the temperature and distill until the internal temperature does not exceed 150°C, then stop the distillation. Evaporate the alkanol and dry it with anhydrous sodium sulfate, then add 20g of anhydrous sodium carbonate and stir for 5-10 minutes (the pH value of the alkanol solution should be neutral at this time), filter immediately, and the filtrate is subjected to normal pressure fractionation, and the collection column The fraction with a top temperature of 110-113°C yielded 800.38 g of a mixture of 2-bromopentane and 2-pentanol. The content of 2-bromopentane was 34.98%.

[0031] Step B: Add 3...

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Abstract

The present invention relates to a preparation method of a drug pentobarbital (1) for sedation, hypnosis, pre-anesthesia administration and anti-convulsion, and provides a new preparation process for preparing high-purity pentobarbital (I) from diethyl ethylmalonate, wherein the process comprises three steps: A, bromination; B, alkylation; and C, cyclization, acidification, and purification. According to the present invention, the method has advantages of simple operation, short production cycle, low energy consumption, mother liquor circulation, less three-waste, stable process, good product quality, high product purity, isomer impurity content of less than 0.1%, high yield and low production cost, and is suitable for industrial production.

Description

technical field [0001] The invention belongs to the field of chemical drug preparation, and in particular relates to a preparation method for 5-ethyl-5-(1-methylbutyl)barbituric acid, which is used for sedation, hypnosis, drug administration before anesthesia and anticonvulsant. Background technique [0002] The preparation method of relevant bibliography report pentobarbital has following several; Chemical reagent 2011,33 (9), the paper " synthetic technique research of pentobarbital sodium " of 857~858 reports, uses 2-bromopentane and A synthetic process for preparing 2-ethyl-2-(1-methylbutyl)-diethyl malonate by reacting with diethyl ethyl malonate, and then reacting with urea to prepare pentobarbital. Since the 2-bromopentane used is an analytical reagent produced by Beijing Qinghongfu Technology Co., Ltd., its content is marked ≥99.0%, and the content of 2-bromopentane is only about 95% by gas chromatography, of which 3-bromopentane The alkane content accounts for abou...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D239/62
CPCC07D239/62
Inventor 朱连博徐豪杰赵帅
Owner SHANDONG XINHUA PHARMA CO LTD
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