Bis(heteroaryl)piperazine (BHAP) reverse transcriptase inhibitors: structure-activity relationships of novel substituted indole analogs and the identification of 1-[(5-methanesulfonamido-1H-indol-2-yl)carbonyl]-4-[3-[(1-methylethyl)amino]pyridinyl]piperazinemonomethanesulfonate (U-90152S), a second-generation clinical candidate | doi.page