Reaction of 2, 2-dichloro-2-(4′-nitrophenyl) acetonitrile with mercury (II) oxide/pyridinium poly (hydrogen fluoride),(aqueous work-up), gave 2, 2-difluoro-2-(4′-nitrophenyl) acetamide, from which were made the parent acid and thence its acid chloride. This and ethyl propanedioate/methyl lithium afforded ethyl 4, 4-difluoro-4-(4′-nitrophenyl)-3- oxobutanoate, converted by SF4/HF into ethyl 3, 3, 4, 4-tetrafluoro-4-(4′-nitrophenyl) ...