Synthetic method of benzyl carbazate

A technology of benzyl carbazate and a synthesis method, which is applied in the synthesis field of benzyl carbazate, can solve the problems of harsh reaction conditions, long production cycle, low comprehensive yield and the like, achieves fewer reaction steps, low production cost, The effect of easy availability of raw materials

Inactive Publication Date: 2014-05-28
JIANGSU HUITENG BIOMEDICAL TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This process route has the disadvantages of low comprehensive yield, high cost, harsh reaction conditions and long production cycle

Method used

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  • Synthetic method of benzyl carbazate

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Experimental program
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Effect test

Embodiment 1

[0024] Embodiment 1: the synthesis of crude product of benzyl carbazate

[0025] In a three-necked reaction flask, add hydrazine hydrate (2.0 mol), potassium carbonate (2.0 mol) and 50 mL of tetrahydrofuran, cool the reaction system to -20°C, and add benzyl chloroformate (2.0 mol) dropwise. After the dropwise addition was completed, the reaction was continued for 2 hours, potassium carbonate was removed by filtration, and washed with water. The organic phase was concentrated to obtain the product (yield 95.0%, purity 96.0%, high performance gas chromatography (GC) internal standard method).

Embodiment 2

[0026] Embodiment 2: Purification of crude product of benzyl carbazate into salt

[0027] In a three-necked reaction flask, 40.0 g of crude benzyl carbazate (96.0% purity, high-performance gas chromatography (GC) internal standard method) and 400 mL of dichloromethane were added, and 80 mL of 30% hydrochloric acid was added dropwise to the reaction system. Solids precipitated in the reaction system. Add 150 mL of water to the reaction system until the solid part dissolves. The organic layer was separated and the aqueous layer was retained. Add 80 mL of ammonia water dropwise to the aqueous layer until the solution becomes alkaline. The aqueous layer was extracted three times with 250 mL of dichloromethane. The organic phase was concentrated to obtain 36.0 g of pure benzyl carbazate (99.5% purity, high performance gas chromatography (GC) internal standard method, yield 90.0%).

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Abstract

The invention relates to a synthetic method of benzyl carbazate. The method comprises the following steps of: a), dissolving hydrazine hydrate in a solvent and adding an alkali; b), controlling the reaction temperature to be 20-80 DEG C, dropping benzyl chloroformate; c), removing impurities after salt forming reaction of an obtained crude product; and d), performing basic dissociation of an obtained salt to obtain a pure f benzyl carbazate product. The synthetic method has the advantages of simple operation, good safety, high yield and low production cost, so as to meet a large demand of volume production of new pesticide indoxacarb and other fine chemical products on the key intermediate-benzyl carbazate.

Description

technical field [0001] The invention relates to a method for synthesizing benzyl carbazate. Background technique [0002] With the increase of the world's population and the continuous enhancement of human awareness of sustainable development, people's demand for the coordinated development of food and the environment has become increasingly prominent, but the high yield of food cannot do without the ecological environment created by herbicides and pesticides. favorable growing environment. Since the birth of suicide insecticides, their development has been limited by their activity, selectivity, and safety. Most of the insecticides put on the market have caused insect pests to become resistant due to their long-term and excessive use. The problems of pesticide safety and drug resistance require that old varieties be eliminated continuously, and varieties with new structure types or new mechanisms of action be developed. With people's emphasis on safety, its biological rat...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C281/02
Inventor 胡惜朝葛忠平王小兵
Owner JIANGSU HUITENG BIOMEDICAL TECH
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