Abstract:
A method for the preparation of pyrazolo [3, 4-hl pyridines,
i
pyrazolo [1, 5-al pyrimidine and triazolo [1, 5-al pyrimidines from
aminopyrazoles and amino triazoles was developed. 5-Amino-3-
methyl-1-phenyl pyrazole when reacted with benzaldehyde give the
Schiff base which on reaction with acetophenone gives the
corresponding pyrazolo 13, 4-hJ pyrimidines (i). The reaction of 3-
amino-4-cyanopyrazole under similar conditions gave nitrogen
bridgehead 11, 5-al in the form of pyrazolo [1, 5-al-pyrimidines (ii)
while 3-amino-triazole and 3-amino-5-phenyl-triazole also undergo
cyclization to give the condensed systems, pyrazolo [1, 5-al
pyrimidines (ii) and triazolo [1, 5-al pyrimidines (iii) in good yields.
II and III were isolated as their dihydroproducts. The mechanism
for the formation of these products is also proposed. The reaction
products were characterized through their IR, PMR and mass
spectra or elemental analysis. The products obtained from these
reactions were also tested for antibacterial activity.