InChI=1/C13H9N5O2/c1-2-20-13(19)11-9-7-16-12-8(5-14)6-17-18(12)10(9)3-4-15-11/h3-4,6-7H,2H2,1H ethyl 3-cyanopyrazolo[1,5-a]pyrido[3,4-e]pyrimidine-6-carboxylate pyrazolo[1,5-a]pyrido[3,4-e]pyrimidine-6-carboxylic acid, 3-cyano-, ethyl ester