Synthesis of Heterocyclic Compounds Containing Perfluoroalkyl Groups. Reactions of Perfluoro(2-methyl-2-pentene) and Perfluoro(5-aza-4-nonene) with N,S-Dinucleophiles

Perfluoro(2-methyl-2-pentene) and perfluoro(5-aza-4-nonene) react with 1,4,5,6-tetrahydropyrimi-dine-2-thiol, pyridine-2-thiol, and 1,2,4-triazole-3-thiol to afford fused heterocyclic systems, while their reactions with tetrahydrothiazole-2-thione and pyrimidine-2-thiol result in replacement of the fluorine atom at the double bond. Treatment of 3,3,3-trifluoro-1-pentafluoroethyl-2-trifluoromethyl-1-pentenyl isothiocyanate with ammonia gives N-(3,3,3-trifluoro-1-pentafluoroethyl-2-trifluoromethyl-1-propenyl)thiourea which undergoes ring closure to 4-tetrafluoroethylidene-5,5-bis(trifluoromethyl)-4,5-dihydrothiazol-2-amine. Possible cyclization paths and the effect of the 1,3(N,S)-dinucleophile nature on the direction of nucleophilic addition at the double bond are discussed.