A facile synthesis of substituted 4,5,6,7-tetrahydropyrazolo[3,4-d]-pyrimidine and 1,2,3,4-tetrahydropyrazolo[1,5-a]triazine derivatives

Cyclocondensation of 3(5)-alkylamino- and 3(5-arylaminopyrazoles 1a-c and 1d-e with formaldehyde and primary amines affords novel tetrahydropyrazolo[3,4-d]pyrimidines 2 and tetrahydropyrazolo[1,5-a]triazine derivatives 3 respectivley in good yields.