-chloro-3-alkyl-7-methyl-3H-

[1,2,3]triazolo[4,5-d]pyrimidine (2a-e). Further reaction of compounds (2a-e) with NaN3 in

EtOH was resulted in various derivatives of novel heterocyclic system of tetrazolo[1,5-

a][1,2,3]triazolo[4,5-d...