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Method for preparing 5-methylbenzimidazole-2-methyl carbamate

A technology of methyl carbamate and methyl cyanocarbamate, which is applied in the field of preparation of fungicides, can solve the problems of long reaction steps, difficulty in industrial production, and high toxicity, and achieve the effects of mild reaction conditions, reduced dosage, and low toxicity

Inactive Publication Date: 2012-02-15
NANJING FORESTRY UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, only Ernest Lacey et al. (Biochemical Pharmacology, Vol.34, No.7, pp.1073-1077, 1985) have reported acetylation, nitration, hydrolysis, reduction, ring formation, rearrangement, etc. The step prepares 5-methylbenzimidazole-2-methyl carbamate, wherein the reaction step is too long, and the reagents used, such as stannous chloride, cyanogen bromide, isothiourea, etc., are more toxic and difficult for industrialized production

Method used

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  • Method for preparing 5-methylbenzimidazole-2-methyl carbamate
  • Method for preparing 5-methylbenzimidazole-2-methyl carbamate
  • Method for preparing 5-methylbenzimidazole-2-methyl carbamate

Examples

Experimental program
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Effect test

Embodiment 1

[0032] In a 250mL four-necked flask with a thermometer and a stirring device, add 16.8g of 50% cyanamide solution (containing 0.2mol of cyanamide), 60ml of methanol solvent, 64g of 25% NaOH solution (containing 0.4mol of NaOH) and 0.5 g benzyltrimethylammonium chloride was used as a phase transfer catalyst, and 18.9 g (0.2 mol) of methyl chloroformate was uniformly added dropwise at a rate of 30 g / h, kept at 45 ° C for about 3 hours, and the reaction solution was cooled, and then poured into a large amount of ice-water mixture, white crystals are precipitated, suction filtration under 760mmHg vacuum condition, the filter cake is washed with methanol and washed to neutrality successively, and dried to obtain 18.7g of methyl cyanocarbamate sodium salt, the yield is 76.8 %.

[0033] In a 250mL four-necked flask equipped with a thermometer and a stirring device, mix and react 18.3g (0.15mol) of sodium methyl cyanocarbamate and 30ml of 5mol / L hydrochloric acid (containing 0.15mol o...

Embodiment 2

[0036] In a 250mL four-necked flask with a thermometer and a stirring device, add 33.6g of 50% cyanamide solution (containing 0.4mol of cyanamide), 60ml of methanol solvent, 64g of 25% NaOH solution (containing 0.4mol of NaOH) and 0.5 g benzyltrimethylammonium chloride was used as a phase transfer catalyst, and 18.9 g (0.2 mol) of methyl chloroformate was uniformly added dropwise at a rate of 30 g / h, kept at 45 ° C for about 3 hours, and the reaction solution was cooled, and then poured into a large amount of ice-water mixture, white crystals are precipitated, suction filtration under 760mmHg vacuum condition, the filter cake is washed with methanol and washed to neutrality successively, and dried to obtain 21.0g of methyl cyanocarbamate sodium salt, the yield is 86.0 %.

[0037] In a 250mL four-neck flask equipped with a thermometer and a stirring device, mix and react 18.8g (0.15mol) of sodium methyl cyanocarbamate and 60ml of 5mol / L hydrochloric acid (containing 0.3mol of h...

Embodiment 3

[0040] In a 250mL four-necked flask with a thermometer and a stirring device, add 33.6g of 50% cyanamide solution (containing 0.4mol of cyanamide), 60ml of methanol solvent, 96g of 25% NaOH solution (containing 0.6mol of NaOH) and 0.5 g benzyltrimethylammonium chloride was used as a phase transfer catalyst, and 18.9 g (0.2 mol) of methyl chloroformate was uniformly added dropwise at a rate of 30 g / h, kept at 45 ° C for about 3 hours, and the reaction solution was cooled, and then poured into a large amount of ice-water mixture, white crystals are precipitated, suction filtration under 760mmHg vacuum condition, the filter cake is washed with methanol and washed to neutrality successively, and dried to obtain 20.1g of methyl cyanocarbamate sodium salt, the yield is 82.2 %.

[0041] In a 250mL four-necked flask equipped with a thermometer and a stirring device, mix and react 18.3g (0.15mol) of sodium methyl cyanocarbamate and 50ml of 5mol / L hydrochloric acid (containing 0.25mol o...

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Abstract

The invention discloses a method for preparing 5-methylbenzimidazole-2-methyl carbamate. Three reaction steps, namely cyanamide formation, acidification and ring closing are performed, operating procedures are simplified, strong base such as sodium hydroxide is adopted for cyanamide formation, hydrochloric acid is adopted for acidification, sodium thiosulfate is adopted for catalyzing ring closing, waste acid is reduced, and pollutants are reduced on the premise of ensuring product quality and yield. The method comprises the following step of: performing cyanamide formation reaction, acidification reaction and ring closing reaction on methylclhlorofonmate serving as a raw material to obtain the product, wherein in the cyanamide formation reaction, the methylclhlorofonmate is reacted with cyanamide under the alkaline condition to form methylcyanocarbamate salt; in the acidification reaction, the methylcyanocarbamate salt is reacted with the hydrochloric acid to form methylcyanocarbamate; and in the ring closing reaction, the methylcyanocarbamate and 4-methoxy-o-phenylenediamine are subjected to condensation reaction to form the 5-methylbenzimidazole-2-methyl carbamate.

Description

technical field [0001] The present invention relates to a kind of preparation method of bactericide, more specifically relate to a kind of preparation method of 5-methylbenzimidazole-2-carbamate methyl ester namely 5-methylcarbendazim. Background technique [0002] 5-Methylbenzimidazole-2-carbamate, namely 5-methylcarbendazim, is a highly efficient, broad-spectrum, and low-toxic systemic fungicide with stable chemical properties and low toxicity. The half-lethal dose of acute toxicity is LD50 value: oral administration to rats is greater than 20g / kg (better than the LD50 value of carbendazim, which is 15g / kg). It belongs to the high-efficiency broad-spectrum fungicide, which can be absorbed by plants and transferred to other parts through conduction, interfering with the mitosis of germ cells and inhibiting their growth. It has the control effect on diseases caused by fungi (such as Deuteromycetes, polyascomycetes, etc.) of various crops, and can be used for foliar spraying...

Claims

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Application Information

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IPC IPC(8): C07D235/32A01P3/00
Inventor 程康华顾晓利黄涛
Owner NANJING FORESTRY UNIV
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