Preparation method and applications of azimsulfuron key intermediate

A technology of tetrazole and pyrazole, applied in the new preparation, the application field in the preparation of rimsulfuron-methyl tetrazole, can solve the problems of adverse environmental impact, long route, environmental pollution, etc., and achieve the goal of being suitable for industrial production and improving reaction Efficiency, the effect of reducing environmental pollution

Active Publication Date: 2016-03-09
JIANGXI ANLIDA CHEM CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This route has the following disadvantages: the route is long; expensive methyl iodide is used for methylation, and the methylation yield is only 50%; the total yield of the whole route is about 17.0%; the benzyl mercaptan used has a pungent smell , Chlorine gas is highly corrosive and has adverse effects on the environment
But the disclosed method of above-mentioned two patent documents needs to pass into a large amount of SO 2 Gas, polluting the environment, and inconvenient to operate

Method used

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  • Preparation method and applications of azimsulfuron key intermediate
  • Preparation method and applications of azimsulfuron key intermediate
  • Preparation method and applications of azimsulfuron key intermediate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0058] Example 1 Preparation of 1-methyl-4-(2-methyl-2H-tetrazol-5-yl)-1H-pyrazole-5-sulfonamide

[0059] Step 1, Synthesis of 2-Methoxymethenylmalononitrile

[0060]

[0061] Add 53g (0.5mol) trimethyl orthoformate, 33g (0.5mol) malononitrile, and 200mL acetic anhydride into a 500mL reaction flask equipped with a reflux tube and a thermometer. Under electric stirring, heat to reflux for 6h, then Distill out low-boiling solvents such as acetic anhydride and by-product methyl acetate. Cool to room temperature (solids are precipitated at this time), add appropriate amount of methanol, wait until the solids are completely dissolved, add activated carbon for decolorization, filter while hot, freeze the filtrate in the refrigerator for 1-3h, precipitate solids, filter with suction, and wash the filter cake with methanol. After drying, 41.04 g of the title compound (white solid) was obtained with a yield of 67.4%.

[0062] m / z:108[M+1] + .

[0063] Step 2. Synthesis of 1-methyl-4-cyano-5-...

Embodiment 2

[0083] Example 2 Preparation of 1-methyl-4-(2-methyl-2H-tetrazol-5-yl)-1H-pyrazole-5-sulfonamide

[0084] Step 1, Synthesis of 2-Methoxymethenylmalononitrile

[0085]

[0086] Add 53 g (0.5 mol) trimethyl orthoformate, 33 g (0.5 mol) malononitrile, and 200 mL acetic anhydride into a 500 mL reaction flask equipped with a reflux tube and a thermometer. Under electric stirring, heat and reflux for 10 hours, then Distill out low-boiling solvents such as acetic anhydride and by-product methyl acetate. Cool to room temperature (solids are precipitated at this time), add appropriate amount of methanol, wait until the solids are completely dissolved, add activated carbon for decolorization, filter while hot, freeze the filtrate in the refrigerator for 1-3h, precipitate solids, filter with suction, and wash the filter cake with methanol. After drying, 42 g of the title compound (white solid) was obtained with a yield of 69%

[0087] m / z:108[M+1] + .

[0088] Step 2. Synthesis of 1-methyl-4...

Embodiment 3 4

[0108] Example 3 Synthesis of Tetrazosulfuron

[0109]

[0110] 60.5 g (0.25 mol) of 1-methyl-4-(2-methyl-2H-tetrazol-5-yl)-1H-pyrazole-5-sulfonamide prepared according to the method described in Example 2 , (4,6-Dimethoxypyrimidin-2-yl) phenylcarbamate 68.7g (0.25mol), potassium carbonate 55.2g (0.4mol) and 200ml dioxane were put into the reaction flask, stirred to dissolve, Then stir at 40-50°C for 5h. Most of the solvent was evaporated under reduced pressure, 200ml of water was added, neutralized with hydrochloric acid to neutral pH, filtered, the filter cake was washed with water, and dried to obtain 99.4 g of the title compound with a yield of 93.3%. Melting point: 173-176, HPLC purity 98.6%.

[0111] m / z: 421.

[0112] 1 H-NMR(CDCl3): δ2.50(s, CH 3 ), 2.51(s, CH 3 ),3.81(s, 2CH 3 O), 4.67 (s, CH), 5.80 (s, CH-Pyrimidin).

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Abstract

The present invention provides a preparation method of 1-methyl-4-(2-methyl-2H-tetrazole-5-yl)1H-pyrazole-5-sulfamide. The preparation method comprises that trimethyl orthoformate and malononitrile are adopted as starting raw materials, a three-step reaction is performed to obtain 1-methyl-5-amino-4-(tetrazole-5-yl)pyrazole, the 1-methyl-5-amino-4-(tetrazole-5-yl)pyrazole reacts with dimethylsulfate in the presence of an acid-binding agent to obtain 2-methyl-5-(1-methyl-5-amino-1H-pyrazole-4-yl)-2H-tetrazole, the 2-methyl-5-(1-methyl-5-amino-1H-pyrazole-4-yl)-2H-tetrazole is subjected to a sodium nitrite diazo-reaction under an acid condition, the obtained material reacts with a sodium sulfite-copper chloride-acetic acid mixture, and finally hydrolysis with ammonia is performed to obtain the target product. The present invention further provides a preparation method of azimsulfuron prepared from the 1-methyl-4-(2-methyl-2H-tetrazole-5-yl)1H-pyrazole-5-sulfamide. The preparation method of the present invention has characteristics of short reaction route, environmental protection raw materials, and high yield.

Description

Technical field [0001] The invention belongs to the field of organic chemistry, and specifically relates to a key intermediate of the paddy field herbicide tetrazosulfuron, 1-methyl-4-(2-methyl-2H-tetrazol-5-yl)-1H -A new preparation method of pyrazole-5-sulfonamide and its application in the preparation of tetrazosulfuron. Background technique [0002] Tetrazosulfuron is a paddy field herbicide developed by DuPont. Its chemical name is 1-((4,6-dimethoxypyrimidin-2-yl)-3-(1-methyl-4-(2-methyl) 2-H-tetrazol-5-yl)pyrazole)-5-ylsulfonylurea, the pure product is almost white crystals, the melting point is 170-173°C, and the structural formula is shown in 1. [0003] [0004] Tetrazosulfuron is an acetolactate synthase inhibitor, especially for the biochemical synthesis of branched amino acids. Through this mechanism, sulfimuron-methyl interferes with the cell division and growth of weeds, which can effectively control a variety of broad-leaved weeds and cyperaceae weeds in paddy fiel...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D403/04C07D403/14
CPCC07D403/04C07D403/14
Inventor 范恩荣高荣明高勤伟
Owner JIANGXI ANLIDA CHEM CO LTD
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