文献类型：专利

英文题名：Preparation of pyrazolidone-type compound involves adding 2,3-dichloro pyridine into reactor, adding hydrazine hydrate solution in organic solvent, heating, refluxing, adding alkali, separating out solid, filtering and washing by water

作者：LI G

机构：[1]UNIV EAST CHINA SCI&TECHNOLOGY

申请号：CN102584694-A

申请日：2012-01-06

公开日：2012-07-18

语种：英文

收录：DERWENT

摘要：NOVELTY - 2,3-Dichloro pyridine is added into reactor, and hydrazine hydrate solution is added in an organic solvent, heated and refluxed, cooled, filtered and washed by water, to obtain (3-chloro-pyridin-2-yl)-hydrazine. The obtained product is added to the (Z)-but-2-enedioic acid diethyl ester, alkali is added, heated and refluxed for 5 minutes, continuously reflowed to 2-hydrazine-3-chlorine pyridine, cooled, solid is separated out, water is added to dilute, filtered, and washed by water, to obtain ethyl 2-(3-chloropyridin-2-yl)-5-oxopyrazolidine-3-carboxylate. USE - Preparation of pyrazolidone-type compound. ADVANTAGE - The pyrazolidone-type compound is efficiently prepared with high yield. DETAILED DESCRIPTION - 2,3-Dichloro pyridine is added as raw material into a reactor, and hydrazine hydrate solution is added in an organic solvent, heated and refluxed, cooled to room temperature, filtered and washed by water, to obtain (3-chloro-pyridin-2-yl)-hydrazine. The obtained product is added to the (Z)-but-2-enedioic acid diethyl ester, alkali is added, heated and refluxed for 5 minutes, diethyl maleate is added, continuously reflowed to 2-hydrazine-3-chlorine pyridine, cooled to room temperature, solid is separated out, water is added to dilute, filtered, and washed by water, to obtain ethyl 2-(3-chloropyridin-2-yl)-5-oxopyrazolidine-3-carboxylate.