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

Molecules. 2009 Feb 13;14(2):777-84. doi: 10.3390/molecules14020777.

Abstract

To synthesize 4-chloro-5-methoxy-2-(b-trifluoroethyl)-3(2H)-pyridazinone (4), the reactions of 4-chloro-5-methoxy-3(2H)-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(2H)-pyridazinone (7) and 4-chloro-2-methyl-5-(b-trifluoroethoxy)-3(2)-pyridazinone(8).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Ethanol / chemistry
  • Fluorine / chemistry*
  • Ions / chemistry*
  • Molecular Structure
  • Pyridazines / chemistry*
  • Salts / chemistry

Substances

  • Ions
  • Pyridazines
  • Salts
  • Fluorine
  • Ethanol