| Abstract |
The reaction of aminonitrones (RC)-C-1(NH2) = N+(Me)O- (R-1 = Alk, Ar) with isocyanides (RNC)-N-2 (R-2 = Alk, Ar; 1.2 equiv.) and Br-2 (1 equiv.) conducted in CHCl3 (RT, 5 min) gives 2-methyl-5-amino-1,2,4-oxadiazolium bromides in good to excellent yields (65-95\%; 16 examples). These species are highly electrophilically activated and 5-cyclohexylamino-2-methyl-3-phenyl-1,2,4-oxadiazolium bromide, taken as a model compound for the reactivity study, reacts rapidly under mild conditions with hydroxylamine, hydrazine, or benzamidine,to give 5-cyclohexylamino-3-phenyl-1,2,4-oxadiazole (88\%), 5-cyclo-hexylamino-3-phenyl-1,2,4-triazole (95\%), and 2-cyclohexylamino-4,6-diphenyl-1,3,5-triazine (64\%), respectively. Treatment of the oxadiazolium salt with excess water provides N-benzoyl-N -cyclohexylurea (95\%). |
