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Method for synthesizing 3-chloro-5-amino-1H-pyrazolyl-4-ethyl formate

A technology of ethyl formate and a synthetic method, applied in directions such as organic chemistry, can solve the problems of troublesome post-processing, many by-products, long synthesis route, etc., and achieves the advantages of convenient operation and post-processing, high total yield and easy cost. Effect

Active Publication Date: 2014-11-19
SUZHOU KANGRUN PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The derivative of 3-bromo-5-amino-1H-pyrazole-4-carboxylic acid ethyl ester is a non-commercialized reagent, and the synthetic route for preparing this raw material is long and the cost is high; in the reaction with butyllithium, the active site of the reaction Many points lead to complex reaction, many by-products, troublesome post-processing and low yield

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0015] Step 1: 2-aminopyrazoline[1,5-α]pyrimidine-3-acid ethyl ester

[0016] 1,1,4,4-Tetramethoxypropane (25.7 g, 156 mmol) was added to ethyl 3,5-diamino-1H-pyrazole-4-carboxylate (29.6 g, 173 mmol ) in 2M hydrochloric acid aqueous solution (120 mL). The mixture was stirred at this temperature for 1 hour and then cooled. After adding saturated aqueous sodium bicarbonate solution to pH = 9, the solution was extracted with ethyl acetate. The organic phase was dried with anhydrous sodium sulfate and pulled Drying. The residue was subjected to column chromatography to obtain 2-aminopyrazoline[1,5-α]pyrimidine-3-oic acid ethyl ester (28.7g, 89%).

[0017] 1 HNMR (400MHz, CDCl 3 ): 1.46 (t, 3 H), 4.50 (m, 2 H), 5.52 (s, 2 H), 6.84 (m, 1 H), 8.45 (d, 1 H), 8.57 (d, 1 H).

[0018] The second step: the synthesis of 2-chloropyrazoline [1,5-α] pyrimidine-3-acid ethyl ester

[0019] At 0-5°C, an aqueous solution (24 mL) of sodium nitrite (8.46 g, 123 mmol) was added dropwise to ethy...

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Abstract

The invention relates to a method for synthesizing 3-chloro-5-amino-1H-pyrazolyl-4-ethyl formate. The method comprises the following steps of: condensing 3,5-diamino-1H-pyrazolyl-4-ethyl formate which is taken as a raw material and 1,1,3,3-tetramethoxypropane to obtain 2-aminopyrazolo[1,5-alpha]pyrimidine-3-ethyl gallate, reacting 2-aminopyrazolo[1,5-alpha]pyrimidine-3-ethyl gallate with sodium nitrite in the presence of cuprous chloride and hydrochloric acid to obtain 2-chloropyrazolo[1,5-alpha]pyrimidine-3-ethyl gallate, and finally, reacting 2-chloropyrazolo[1,5-alpha]pyrimidine-3-ethyl gallate with hydrazine hydrate in ethanol to obtain 3-chloro-5-amino-1H-pyrazolyl-4-ethyl formate. The method for synthesizing 3-chloro-5-amino-1H-pyrazolyl-4-ethyl formate is low in cost, convenient to operate and easy to scale-up, the raw material is readily available, the route is concise, the post-treatment is convenient, the total yield is high, and the mass production can be performed.

Description

technical field [0001] The invention relates to a method for synthesizing ethyl 3-chloro-5-amino-1H-pyrazole-4-carboxylate. Background technique [0002] Ethyl 3-chloro-5-amino-1H-pyrazole-4-carboxylate is an important intermediate in organic synthesis, and its derivative structures are also contained in many drug candidate molecular structures (WO2006133261; WO200746548; WO20084698; WO20113065). It has superior modifiable characteristics: (1) The chlorine atom in the molecule is a highly active reaction site, which can undergo substitution reactions with some fragments or intermediates containing heteroatoms, through the chlorine atom and the adjacent ester group Reacting with derivatives of urea or thiourea can synthesize pyrimidopyrazoles with very good biological activity (Eur.J.Med.Chem., 2011, 46(2), 631, etc.); (2) the amino group in the molecule It can also be modified to obtain a series of different organic compounds and candidate drug active molecules, [0003] ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D231/38
Inventor 徐卫良左兵徐炜政
Owner SUZHOU KANGRUN PHARMA