Fluorinated acetylenes. Part V. Reaction of trifluoronitroso-methane with certain NN-bistrifluoromethylamino-substituted acetylenes

Abstract

Trifluoronitrosomethane reacts with acetylenes of the type (CF₃)₂N·C⋮CR [where R = H, Br, CF₃, or N(CF₃)₂] at ca, 90° to give high yields of 1 : 1 adducts. The structures of the adducts have been assigned on the basis of their i.r., n.m.r., and mass spectra. The symmetrical acetylene [R = N(CF₃)₂] forms only one adduct, perfluoro(2-methyl-4-dimethylamino-2,5-diazahex-4-en-3-one)(CF₃)₂N·CO·C(:N·CF₃)·N(CF₃)₂, but the acetylenes (R = H, Br, or CF₃) give the adducts (CF₃)₂N·CO·CR:N·CF₃ and (CF₃)₂N·C(COR):N·CF₃, with the former predominating. NN-Bistrifluoromethylprop-1-ynylamine reacts with trifluoronitrosomethane at 120° to give the 1 : 1 adduct 1,1,1,6,6,6-hexafluoro-4-methyl-2-trifluoromethyl-2,5-diazahex-4-en-3-one, (CF₃)₂N·CO·CH(CH₃):N·CF₃, and two unidentified products. The formation of the adducts is explained by the initial formation of the corresponding cyclic oxazetines which then ring open.