Ethyl (1,1,1-trifluoro-2-propylidene)carbazate is converted with tert-butyl
hypochlorite to the 2-chloro-1,1,1-trifluoro-2-propyl azo compound 2, whic
h reacts with antimony pentachloride to produce the trifluoromethylated 1-a
za-2-azoniaallene salt 3 as a highly reactive intermediate. The cation 3 is
employed as a CF3-containing synthon for the preparation of the 5-trifluor
omethylated 1H-1,2,4-triazolium picrates 6a-e.