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Pyrazolo[1,5-a]pyridine-3-carboxylate derivative synthetic method

A synthesis method and technology of pyridine acetate, applied in directions such as organic chemistry, can solve problems such as difficult industrial production, difficult separation, poor selectivity, etc., and achieve the effects of high selectivity, easy availability of raw materials, and mild reaction conditions

Inactive Publication Date: 2017-09-15
上海毕得医药科技股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The technical problem solved by the present invention is that the synthesis of pyrazolo[1,5-a]pyridine-3-carboxylate derivatives in the prior art has low yield, poor selectivity and difficult separation, and it is difficult to scale up to industrial production And other issues

Method used

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  • Pyrazolo[1,5-a]pyridine-3-carboxylate derivative synthetic method

Examples

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Embodiment 1

[0035] Example 1 Synthesis of methyl 6-fluoropyrazolo[1,5-A]pyridine-3-carboxylate

[0036]

[0037] (1) Compound 1' (600g, 3.50mol, 1.0eq) was added to 6L of isopropanol, then DMF-DMA (507.2g, 4.20mol, 1.2eq) was added, and the reaction solution was heated to reflux for 3 hours;

[0038] (2) After TLC monitors that the reaction is complete, cool the reaction solution to room temperature, then add hydroxylamine hydrochloride (316.2g, 4.55mol, 1.3eq), anhydrous methanol 1.5L, continue to heat the reaction to reflux for 6 hours, and TCL monitors that the reaction is complete Finally, concentrate the reaction solution, then add an appropriate amount of water to the reaction solution and stir until the solid does not increase, filter, wash the filter cake with water, and dry to obtain compound 3' (684.3g, 3.22mol), the yield is about 92%

[0039] (3) Add compound 3' (600g, 2.82mol, 1.0eq) into 6L of THF, cool the reaction to about 0 degrees, slowly add trifluoroacetic anhydride...

Embodiment 2

[0041]Example 2 Synthesis of methyl 4-methylpyrazolo[1,5-A]pyridine-3-carboxylate

[0042]

[0043] (1) Compound 1" (300g, 1.82mol, 1.0eq) was added to 1.8L of isopropanol, then DMF-DMA (259.8g, 2.18mol, 1.2eq) was added, and the reaction solution was heated to reflux for 2.5 hours;

[0044] (2) After TLC monitors that the reaction is complete, cool the reaction solution to room temperature, then add hydroxylamine hydrochloride (164.7g, 2.37mol, 1.3eq), anhydrous methanol 0.9L, continue to heat the reaction to reflux for 5 hours, and TCL monitors that the reaction is complete Finally, concentrate the reaction solution, then add an appropriate amount of water to the reaction solution and stir until the solids no longer increase, filter, wash the filter cake with water, and dry to obtain compound 3" (330.8g, 3.22mol), with a yield of about 87.3%;

[0045] (3) Add compound 3" (300g, 1.44mol, 1.0eq) into 3L of THF, cool the reaction to about 0 degrees, slowly add trifluoroaceti...

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Abstract

The invention relates to the field of organic synthesis, and discloses a method for synthesizing a pyrazolo[1,5-a]pyridine-3-carboxylate derivative. The method comprises the following step: 1) 2-pyridine acetate or substitute 2-pyridine acetate and N,N-dimethylformamide dimethyl acetal are subjected to a reaction; 2) hydroxylamine hydrochloride is continuously added for a reaction to obtain a compound III; and 3) the compound III and trifluoroactic anhydride are subjected to the reaction to generate the product. After the reaction is completed, water is added, and the pH value is adjusted to neutrality, extraction is carried out and the organic phases are merged, and then the steps of drying, concentration and re-crystallization are carried out. The synthetic method has the advantages of easy acquisition of the raw materials, mild reaction condition and high yield; whether the raw materials have a symmetrical structure or not, the target product can be specifically obtained, post-treatment and purifying are easily operated, and amplification production can be realized.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a synthesis method of pyrazolo[1,5-a]pyridine-3-carboxylate derivatives. Background technique [0002] Pyrazolopyridine derivatives are a very important class of nitrogen-containing fused heterocyclic compounds, which have good application prospects in pharmacological research. [0003] For example, this type of compound has significant curative effect and biological activity in the prevention and treatment of Klinefelter-negative and positive bacteria, various malignant tumors, neurological diseases, osteoporosis and Alzheimer's disease; meanwhile, in the field of pesticides, heterocyclic compounds Become the mainstream of the development of new pesticides, making pesticides enter a new era of ultra-efficient and pollution-free green pesticides. [0004] There are mainly three kinds of commonly used pyrazolopyridine derivatives, namely pyrazolo[3,4-b]pyridine, pyrazolo[4,3-c]py...

Claims

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Application Information

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IPC IPC(8): C07D471/04
CPCC07D471/04
Inventor 米涛冉李新玲巫循伟张锐豪黄良富
Owner 上海毕得医药科技股份有限公司
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