Novel Nonnucleoside Inhibitors of HIV-1 Reverse Transcriptase. 8. 8-Aryloxymethyl- and 8-Arylthiomethyldipyridodiazepinones¹

Nevirapine (I) is the first human immunodeficiency virus type 1 (HIV-1) nonnucleoside reverse transcriptase (RT) inhibitor to reach regulatory approval. As a result of a second generation program around the tricyclic core system of nevirapine, 2-chloro-5,11-dihydro-11-ethyl-5-methyl-8-(2-(pyridin-4-yl)ethyl)-6H-dipyrido[3,2-b:2',3'-e][1,4]diazepin-6-one (II)(1a) and 2-chloro-5,11-dihydro-11- ethyl-5-methyl-8-phenylethyl-6H-dipyrido[3,2-b :2',3'-e][1,4]diazepin-6-one (III)(1a) were identified as broad spectrum HIV-1 RT inhibitors. A detailed examination of replacing either of the methylenes of the 8-ethyl linker of II or III is presented. It was found that 8-aryloxymethyl and 8-arylthiomethyl are the preferred pattern of substitution for potency against RT. The most potent compounds were further evaluated against a panel of clinically significant mutant RT enzymes (K103N, V106A, G190A, P236L) and in cytotoxicity and in vitro metabolism assays. The most potent compound was 2-chloro-8-phenylthiomethyl analogue 37 which displayed sub-100 nM activity against all HIV-1 RT enzymes tested.