Synthesis and reaction of 1-(N,N-disubstituted amino)pyrazoles.

Abstract

Some 1-(N, N-disubstituted amino) pyrazoles were synthesized by 1, 3-dipolar cyclo-addition of 3-(N, N-disubstituted amino) sydnones with acetylenes. Arylacetylenes gave 3-arylpyrazoles preferentially. The structures were determined by ultraviolet and nuclear magnetic resonance spectroscopy, and further confirmed by catalytic hydrogenolysis and mass spectroscopy. Nitration and halogenation of 3-phenyl-1-aminopyrazoles occurred smoothly at C-4 first and at C-5 subsequently.