Molecules

Methyl carbonium ion migration during the reaction of 4-chloro-5-methoxyl-3 (2H)-pyridazinone with trifluoroethylation agents

Q Li, G Lin, L Liu, Z Yang, LH Zhang

Index: Li, Qin; Lin, Guichun; Liu, Li; Yang, Zhenjun; Zhang, Li-He Molecules, 2009 , vol. 14, # 2 p. 777 - 784

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Citation Number: 4

Abstract

Abstract: To synthesize 4-chloro-5-methoxy-2-(β-trifluoroethyl)-3 (2 H)-pyridazinone (4), the reactions of 4-chloro-5-methoxy-3 (2 H)-pyridazinone (5) with RCH 2 CF 3 (R= I, TsO, MsO, TfO) in different solvents were studied. It was found that methyl group migration took place during this reaction. An oxonium salt 9 was suggested as the active intermediate for the formation of the byproduct 4-chloro-5-methoxy-2-methyl-3 (2 H)-pyridazinone (7) and 4- ...