2-（3-氯-2-吡啶基）-5-氧代-3-吡唑烷甲酸乙酯的合成

Synthesis of ethyl 2-（3-chloro-2-pyridinyl）-5-oxo-3-pyrazolidinecarboxylate

摘要:

以3-氨基吡啶为原料，经取代、重氮化得到2,3-二氯吡啶，再与水合肼经亲电取代制得3-氯-2-肼基吡啶。所得产品无需提纯可直接用于下步反应。所得产物与马来酸二乙酯在氮气保护条件下，以绝对乙醇为溶剂，反应得到有机中间体2-(3-氯-2-吡啶基)-5-氧代-3-吡唑烷甲酸乙酯，反应总收率为48.0%。所得产物经IR、1H NMR确定其结构。并对合成工艺进行优化，所得适宜工艺条件（以3-氯-2-肼基吡啶228.57mmol计）：在无水无氧反应体系中，回流状态下滴加马来酸二乙酯速度为10s/d时，回流反应1h，产率为80.1%。

Abstract:

2,3-dichloropyridine was synthesized from 3-aminopyridine by substitution and diazotization, which reacted with hydrazine to give 3-chloro-2 (1H)-pyridinone by electrophilic substitution.The resultant can be used in the next reaction without purification. Under the protection of nitrogen，absolute ethanol as solvent, Ethyl 3-chloro-2(1H)-pyridinone hydrazone reacted with diethyl maleate to give 2-(3-chloro-2-pyridinyl)-5-oxo-3-pyrazolidinecarboxylate, the total yield was 48.0%. Structure of the products were confirmed by IR and 1H NMR.The synthesis process was optimized, optimization of the reaction conditions were found as follows (base on 228.57 mmol 3-chloro-2(1H)-pyridinone hydrazone): under no water and oxygen, speed of dropping diethyl maleate was 10s/d , reflux 1h, the yield was 80.1%.