Trifluoromethylisocyanide CF 3NC, a source for n-trifluoromethyl-carbimidoyl-compounds CF 3NCXY

Abstract

The new high yield synthesis of trifluoromethylisocyanide by reductive elimination of halogen from N-trifluoromethylcarbimidoyl-dihalogenides allows the study of the structure and reactivity of this reactive compound. In the reaction of trifluoromethylisocyanide with hydrogen halides, N-trifluoromethylcarbimidoyl-halides are formed. From NMR-data we can conclude that both possible isomers are formed, but only one is the major product. In the case of the HF addition the amine CF 3NHCF 2H is formed as a by-product. This amine undergoes HF elimination on treatment with anhydrous KF forming CF 3NCHF. The N-trifluoromethyl- carbimidoyl-halides dimerise slowly at room temperature forming formamidines of the type CF 3N=C ▪ (CF 3)(CX 2H) . In the α-addition of SF 5Br to CF 3NC only one isomer is formed.