Synthèse des pyrido[2,3‐d] el [3,2‐d] ‐s‐triazolo[3,4‐f] pyrimidines el de (pyrazolyl‐1')‐4 pyrido[2,3‐d] et [3,2‐d] pyrimidines

The synthesis of two new heterocycles is described: pyrido‐[2,3‐d]‐.s‐triazolo[ 3,4‐f] pyrimidine and pyrido[3,2‐d]‐.s‐triayzolo‐[3,4‐f] pyrimidine. 4‐[I'‐Pyrazolyl]pyrido[2,3‐d]pyrimidines and 4‐[1′‐pyrazoly1] pyrido[ 3,2‐d] pyrimidine are obtained by the action of 4‐hydrazinopyrido[2,3‐d]pyrimidine and 4‐hydrazinopyrido‐[3,2‐d]pyrimidine with several β‐diketones.