Ji Ya-fei
2009
Citations
0
Influential Citations
0
Citations
Journal
Chinese Journal of Synthetic Chemistry
Abstract
Ethyl 2-(3-chloro-2-pyridinyl)-5-oxo-3-pyrazolidinecarboxylate(5) was prepared from 2,3-dichloropyidine by nucleophilic substitution with aqueous hydrazine,and then cyclization with diethyl maleate. Ethyl 3-bromo-1-(3-chloro-2-pyridinyl)-4,5-dihydro-1H-pyrazole-5-carboxylate(7) was prepared from 5 by esterification with benzenesulfonyl chloride,and then bromination with hydrogen bromide. A key intermediate for preparing chlorantraniliprole,3-bromo-1-(3-chloro-2-pyridinyl)-1H-pyrazole-5-carboxylic acid(1),was synthesized from 7 by dehydrogenation and hydrolysis in overall yield of 39.5%. The structures were confirmed by 1H NMR and MS.