ChemInform Abstract: Polyfunctional Pyrazoles. Part 8. Synthesis of 6‐Alkyl‐2‐aryl‐2H‐pyrazolo[4, 3‐d]pyrimidine‐5, 7(4H, 6H)‐diones (IV) Based on Ethyl 1‐Aryl‐4‐isocyanatopyrazole‐3‐carboxylates (I). Issue 21 (27th May 2014) - Bratenko, M. K.; Barus, M. M.; Vovk, M. V.