Derivatives of 4-hydroxy-5,6,7,8-tetrafluorocoumarin in reactions with o-aminothiophenol

The derivatives of 4-hydroxy-5,6,7,8-tetrafluorocoumarin in reactions with o-aminothiophenol yield products of S-substitution at C-7 atom, 7-substitut ed 5,6,8-trifluorocoumarins afford benzothiazoles as a result of cleavage o f the pyrone cycle, 2-methyl-3-ethoxycarbonyl-5,6,7,8-tetrafluorochromone u ndergoes acidic cleavage to 2-(2-hydroxy-3,4,5,6-tetrafluorophenyl)benzothi azole. S-substituted coumarins in alkaline media suffer decomposition to ac etophenone. In acidic media 3-iminoacetyl-4-hydroxy-5,6,8-trifluoro-7-(2-am inophenylthio)coumarin affords 2-methyl-5,6,8-trifluoro-7-(2-aminophenylthi o)chromone. In condensation of 4-hydroxy-5,6,8-trifluoro-7-(2-aminophenylth io)coumarin in the presence of NaH was isolated 4-hydroxy-5,6-difluoro-2H-p yrano[6,5-a]phenothiazin2-one.