6,8-Diphenyl-8,9-dihydro-7H-pyrimido[4,5-b][1,4]diazepin-4-amine 6,8-Diphenyl-8,9-dihydro-7H-pyrimido[4,5-b][1,4]diazepin-4-ylamine AIDS-149422 AIDS149422 NSC683888