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A kind of preparation method of 1-(3-chloropyridin-2-yl)-3-bromo-1h-pyrazole-5-carboxylate

A technology of chloropyridine and formate, which is applied in the field of preparation of 1--3-bromo-1H-pyrazole-5-carboxylate, can solve the problems of being unsuitable for industrial production, poor atom economy, long steps, etc. Achieve the effects of avoiding the use of oxidizing reagents, less waste, and low cost

Active Publication Date: 2021-06-29
JIANGSU SEVENCONTINENT GREEN CHEM CO LTD
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Problems solved by technology

[0003] The synthetic method of 1-(3-chloropyridin-2-yl)-3-bromo-1H-pyrazole-5-carboxylate in the published patent and reported literature is mainly based on 3-chloro-2-hydrazine Base pyridine as raw material, first react with diethyl maleate to synthesize 1-(3-chloropyridin-2-yl-)-3-hydroxyl-4,5-dihydro-1H-pyrazole-3-ethyl carboxylate , and then reacted with a brominating reagent to obtain ethyl 1-(3-chloropyridin-2-yl-)-3-bromo-4,5-dihydro-1H-pyrazole-5-carboxylate, which was finally oxidized by an oxidizing reagent , to obtain 1-(3-chloropyridin-2-yl)-3-bromo-1H-pyrazole-5-carboxylic acid ethyl ester, the synthetic method step is long, and the yield is low, wherein the first step cyclization reaction yield is only In addition, the oxidation reaction needs to use a large amount of potassium persulfate, the atom economy is poor, and a large amount of three wastes are produced, which is not suitable for industrial production

Method used

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  • A kind of preparation method of 1-(3-chloropyridin-2-yl)-3-bromo-1h-pyrazole-5-carboxylate

Examples

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Effect test

Embodiment 1

[0034] In a 250ml round bottom flask, add 20g (0.139mol) of 3-chloro-2-hydrazinopyridine, 100g of methanol, 9g (0.166mol) of sodium methylate, heat up to reflux, and dropwise add 24.7g of raw material B (R=Me) ( 0.174mol), dripped for 1 hour, refluxed for 2 hours, cooled to 50°C, added 12g of glacial acetic acid, adjusted the pH to 6-7, recovered methanol under negative pressure, then added 100g of water and 20g of methanol, slowly cooled to 0°C, pumped After filtering and drying, 26.5 g of product C (R=Me) was obtained, with a content of 98.7% and a yield of 74.0%.

Embodiment 2

[0036] Add 40g (0.279mol) of 3-chloro-2-hydrazinopyridine, 80g ethanol, and 22.7g (0.333mol) of sodium ethoxide into a 250ml round bottom flask, heat up to reflux, and add 59.2g of raw material B (R=Et) dropwise (0.348mol), after 1 hour of dripping, reflux for 1 hour, cool down to 50°C, add 26g of glacial acetic acid, adjust the pH to 6-7, recover ethanol under negative pressure, then add 150g of water and 40g of ethanol, slowly cool down to 0°C, After suction filtration and drying, 59.8 g of product C (R=Et) was obtained, with a content of 98.5% and a yield of 78.8%.

Embodiment 3

[0038] In a 250ml round bottom flask, add 40g (0.279mol) of 3-chloro-2-hydrazinopyridine, 80g of tert-butanol, 33.1g (0.345mol) of sodium tert-butoxide, heat up to reflux, and dropwise add raw material B (R = Et) 60.4g (0.355mol), 1h dripping, reflux for 1h, cool down to 50°C, add 26g of glacial acetic acid, adjust the pH to 6-7, recover the solvent under negative pressure, then add 180g of water and 20g of ethanol, slowly cool down to 0°C, suction filtered, and dried to obtain 49.2 g of product C (R=Et), with a content of 97.2% and a yield of 64%.

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Abstract

The present invention relates to a kind of preparation method of 1-(3-chloropyridine-2-yl)-3-bromo-1H-pyrazole-5-formate, the preparation method is based on 3-chloro-2-hydrazine Pyridine is the starting material, under alkaline conditions, reacts with butynedioic acid dimethyl or butynedioic acid diethyl ester to obtain 1-(3-chloropyridine-2-yl-)-3-hydroxyl-1H ‑Pyrazole‑5‑formate, 1‑(3‑chloropyridine‑2‑yl‑)‑3‑hydroxy‑1H‑pyrazole‑5‑formate reacts with phosphorus oxybromide to obtain 1‑( 3-Chloropyridin-2-yl)-3-bromo-1H-pyrazole-5-carboxylate. The preparation method of the invention shortens the reaction steps, avoids the use of oxidizing reagents, has simple operation, low cost, less three wastes, high content of target products, and is suitable for industrial production.

Description

technical field [0001] The invention relates to a preparation method of 1-(3-chloropyridin-2-yl)-3-bromo-1H-pyrazole-5-carboxylate. Background technique [0002] 1-(3-Chloropyridin-2-yl)-3-bromo-1H-pyrazole-5-carboxylate is a key intermediate in the synthesis of the insecticide chlorantraniliprole. Chlorantraniliprole is a new type of amide insecticide developed by DuPont in 2000. It is a new type of ryanodine receptor inhibitor with high efficiency, low toxicity and unique mechanism of action. Its main mechanism of action is to induce insect fish The activation of nitine receptors causes the release of endogenous calcium ions, leading to the death of insects, and has special effects on Lepidoptera pests. The market demand for chlorantraniliprole is large, and there is no large-scale production in China, so study its key intermediate 1-(3-chloropyridin-2-yl)-3-bromo-1H-pyrazole-5-carboxylic acid ethyl ester The synthetic method is of great significance. [0003] The synth...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D401/04
CPCC07D401/04
Inventor 张虎吕国雨刘玉超安静顾怡
Owner JIANGSU SEVENCONTINENT GREEN CHEM CO LTD
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