1H-Pyrazolo[3,4-b]pyridine-5-carboxylic acid, 4-(butylamino)-1-ethyl-, ethyl ester 34966-41-1 Cartazolate Ethyl 4-(butylamino)-1-ethyl-1H-pyrazolo[3,4-b]-pyridine-5-carboxylate NSC166873 SQ 65396