Synthesis of 4-(trifluoromethyl)thiocoumarins
摘要
A convenient method for the synthesis of poorly studied 4-(trifluoromethyl)thiocoumarins from 1-[2-(tert-butylthio)phenyl]-2,2,2-trifluoroethanones was developed. Thiopyranone core of 4-(trifluoromethyl)thiocoumarins was constructed by S-acylation of 1-[2-(tert-butylthio)phenyl]-2,2,2-trifluoroethanones with bromoacetyl bromide followed by treatment with triphenylphosphine to give the phosphonium salt and subsequent intramolecular Wittig reaction. S-Acylation of these substrates with acetyl chlorides bearing active methylene group and subsequent intramolecular Knövenagel condensation gave 3-substituted 4-(trifluoromethyl)thiocoumarins.