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Improved method for preparing benzo[d][1,2,3] thiadiazole-7-formic acid trifluoroacetate

A technology of benzothiadiazole and thiadiazole, which is applied in the direction of organic chemistry and can solve the problem of low yield

Inactive Publication Date: 2011-02-16
EAST CHINA UNIV OF SCI & TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] However, due to the existing method for preparing trifluoroethyl benzo[d][1,2,3]thiadiazole-7-carboxylate (especially: from benzo[d][1,2,3]thiadiazole -7-formic acid is produced into benzo[d][1,2,3]thiadiazole-7-formic acid trifluoroethyl ester through esterification) there is a defect that the yield is low (ZL 03116948.1), which limits Application of Trifluoroethyl Benzo[d][1,2,3]thiadiazole-7-carboxylate

Method used

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  • Improved method for preparing benzo[d][1,2,3] thiadiazole-7-formic acid trifluoroacetate
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  • Improved method for preparing benzo[d][1,2,3] thiadiazole-7-formic acid trifluoroacetate

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preparation example Construction

[0017] The preparation method of benzo[d][1,2,3]thiadiazole-7-formic acid trifluoroethyl ester of the present invention comprises the steps:

[0018] (1) Synthesis of methyl m-aminobenzoate:

[0019] Mix m-aminobenzoic acid and methanol, add thionyl chloride dropwise under temperature control, and then heat to reflux until the raw materials are completely converted. The material ratio of m-aminobenzoic acid and thionyl chloride is 1:1.5-4 (equivalent ratio), and the reaction time is 4 hours to 10 hours.

[0020] (2) Synthesis of N-(3-methoxycarbonylphenyl)-thiourea:

[0021] Dissolve methyl m-aminobenzoate in chlorobenzene, add thiocyanate and surfactant in batches, and react at 50°C to 120°C for 8 hours to 15 hours to obtain N-(3-methoxycarbonylphenyl) - Thiourea;

[0022] Wherein: said thiocyanate is potassium thiocyanate, sodium thiocyanate or ammonium thiocyanate, and said surface active agent of the table can be quaternary ammonium salt (such as triethylbenzyl ammonium...

Embodiment

[0035] (1) Synthesis of methyl m-aminobenzoate:

[0036]

[0037] Add 200 mL of anhydrous methanol into a 500 mL three-neck flask, stir with a magnetic force, cool to -5°C in an ice-salt bath, and add m-aminobenzoic acid (34.3 g, 0.25 mol) while stirring. Measure SOCl 2 (65.3mL, 0.9mol) was placed in a constant-pressure dropping funnel and added dropwise, controlling the temperature below 0°C. After the dropwise addition, stir for 15 minutes, remove the ice bath, replace the heating reflux device, and reflux for 5 hours. Spin off residual anhydrous methanol and SOCl 2 , washed the dark pink flocculent product with saturated aqueous sodium bicarbonate solution. Then it was extracted with ethyl acetate, dried, then suction filtered, and concentrated by rotary evaporation to obtain 35.9 g of dark brown oily liquid. Yield 95%. HPLC purity 99.6%.

[0038] (2) Synthesis of N-(3-methoxycarbonylphenyl)-thiourea:

[0039]

[0040] Add methyl 3-aminobenzoate (35.9g, 0.24mol...

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Abstract

The invention relates to a synthesis method of benzo[d][1,2,3] thiadiazole-7-formic acid trifluoroacetate. The synthesis method comprises the following main steps of: performing esterification on m-aminobenzoic acid serving as an initiative raw material and methanol so as to obtain m-aminobenzoic acid methyl ester; in the presence of a surfactant, reacting the m-aminobenzoic acid methyl ester and thiocyanate so as to obtain N-(3-carbomethoxy phenyl)-thiourea; adding bromine into the N-(3-carbomethoxy phenyl)-thiourea in chlorobenzene or glacial acetic acid to perform a cyclization reaction so as to obtain 2-amino-7-carbomethoxy benzothiazole; performing heating and loop opening on the 2-amino-7-carbomethoxy benzothiazole in aqueous solution of KOH and performing diazotization and loop closing under an acid condition so as to obtain 7-carboxylic acid-[1,2,3] diazosulfide; and in the presence of oxalyl chloride, performing an esterification reaction on the 7-carboxylic acid-[1,2,3] diazosulfide and trifluoroethanol so as to obtain a target product. Compared with the prior art, the method increases the yield of the benzo[d][1,2,3] thiadiazole-7-formic acid trifluoroacetate.

Description

technical field [0001] The invention relates to a synthesis method of benzo[d][1,2,3]thiadiazole-7-carboxylic acid trifluoroethyl ester. Background technique [0002] Benzo[d][1,2,3]thiadiazole-7-carboxylate trifluoroethyl ester is the anti-disease activator benzo[d][1,2,3]thiadiazole-7-carboxylate A multi-purpose bioactive substance developed on the basis of methyl ester (BTH). It was first used as a chemical inducer to paclitaxel, a secondary metabolite in yew plant cell culture, and the effect was very significant (ZL 03116948.1). As a plant disease resistance activator, its performance is equivalent to or better than BTH (ZL 200610027833.2), and it is a plant protection product with great application prospects. [0003] However, due to the existing method for preparing trifluoroethyl benzo[d][1,2,3]thiadiazole-7-carboxylate (especially: from benzo[d][1,2,3]thiadiazole -7-formic acid is produced into benzo[d][1,2,3]thiadiazole-7-formic acid trifluoroethyl ester through...

Claims

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Application Information

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IPC IPC(8): C07D285/14
Inventor 赵振江朱维平钱旭红徐玉芳周济陈孟杰
Owner EAST CHINA UNIV OF SCI & TECH
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