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Synthesis process of important pharmaceutical chemical intermediate 4-nitroindole

The technology of a nitroindole and an intermediate, which is applied in a synthesis field of 4-nitroindole, can solve the problems that the product is not easily separated, the atom economy is low, and the process requirements are high, and achieves the realization of large-scale industrial production and product The effect of high purity and simple operation steps

Inactive Publication Date: 2013-10-16
ZHANG JIA GANG VINSCE BIO PHARM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, there are certain deficiencies in the research reported abroad, such as: low atom economy, high process requirements, many side reactions, difficult separation of products, etc., and there are no relevant reports on large-scale production at home and abroad.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0009] The first step, the synthesis of N-(2-methyl-3-nitrophenyl) ethoxymethanimine

[0010] 2-Methyl-3-nitroaniline (60.8g, 0.4mol) was dissolved in a 250ml three-necked flask filled with triethyl orthoformate (80.0g, 0.54mol), and p-toluenesulfonic acid (0.7g, 4mmol) was added ), heated under stirring, and the condensed liquid was collected into a single-necked bottle by a fractional distillation and condensation device. The reaction was maintained at 115° C. for 1.5 hr, and the reaction was stopped. A total of 35.0 g of condensed liquid was collected to obtain 101.3 g of reaction liquid, which was recrystallized by adding n-hexane to obtain N-(2-methyl-3-nitrophenyl)ethoxymethimine (46.6 g, 0.2240 mol).

[0011] The second step, the synthesis of 4-nitroindole

[0012] Add DMF (50ml) and diethyl oxalate (29.2g, 0.2mol) into a 150ml three-neck flask, place in an ice bath, stir and cool. Control the temperature below 5°C, and slowly add potassium ethoxide (16.8 g, 0.2 mol)...

Embodiment 2

[0017] The first step, the synthesis of N-(2-methyl-3-nitrophenyl) ethoxymethanimine

[0018] 2-Methyl-3-nitroaniline (91.2g, 0.6mol) was dissolved in a 500ml three-necked flask filled with triethyl orthoformate (120.0g, 0.81mol), and p-toluenesulfonic acid (1.05g, 6mmol) was added ), heated under stirring, and the condensed liquid was collected into a single-necked bottle by a fractional distillation and condensation device. The reaction was maintained at 120° C. for 1.5 hr, and the reaction was stopped. A total of 55.0 g of condensed liquid was collected to obtain 151.2 g of reaction liquid, which was recrystallized by adding n-hexane to obtain N-(2-methyl-3-nitrophenyl)ethoxymethimine (65 g, 0.3125 mol).

[0019] The second step, the synthesis of 4-nitroindole

[0020] Add DMF (75ml) and diethyl oxalate (43.8g, 0.3mol) into a 250ml three-neck flask, place in an ice bath, stir and cool. Control the temperature below 5°C, and slowly add potassium ethoxide (25.2 g, 0.3 mol)...

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PUM

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Abstract

The invention relates to a synthesis process of an important pharmaceutical chemical intermediate 4-nitroindole. The synthesis process consists of: under the catalysis of p-toluenesulfonic acid, reacting 2-methyl-3-nitroaniline with triethyl orthoformate to produce N-(2-methyl-3-nitrophenyl)ethoxy methylenimine, then reacting the N-(2-methyl-3-nitrophenyl)ethoxy methylenimine with potassium ethoxide and diethyl oxalate to generate 4-nitroindole, then carrying out recrystallization and vacuum sublimation, thus obtaining a light yellow product, i.e. the 4-nitroindole. And the total yield is about 35%.

Description

technical field [0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a synthesis method of 4-nitroindole. Background technique [0002] 4-nitroindole is an important intermediate for the preparation of other simple 4-substituted indoles, and is also an important raw material for the synthesis of dyes and drugs. There are no relevant domestic reports on the synthesis method of 4-nitroindole, and there are many studies abroad. : Such as the synthesis of 4-nitroindole through 2-methyl-3-nitroaniline ring closure, the preparation of 4-nitroindole through m-dinitrobenzene derivatives, and the cyclization of m-phenylnitrophenylhydrazone Preparation of 4-nitroindole by hydrolysis and other methods. [0003] At present, there are certain deficiencies in the research reported abroad, such as: low atom economy, high process requirements, many side reactions, difficult separation of products, etc., and there are no related reports on l...

Claims

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Application Information

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IPC IPC(8): C07D209/08
Inventor 彭学东张梅赵金召陈晓龙
Owner ZHANG JIA GANG VINSCE BIO PHARM
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