Pyrazolo[1,5-a]pyrimidines are purine analogues. They have benefcial properties as antimetabolites in purine biochemical reactions. This division compounds have attracted wide pharmaceutical interest because of their antitrypanosomal activity. | Synthesis of some new pyrazolo 1 5-a pyrimidine pyrazolo 5 1-c triazine 1 3 4-thiadiazole and pyridine derivatives containing 1 2 3-triazole moiety