Improving Druggability of Novel Diarylpyrimidine NNRTIs by a Fragment-Based Replacement Strategy: From Biphenyl-DAPYs to Heteroaromatic-Biphenyl-DAPYs

A series of novel heteroaromatic-difluoro-biphenyl-diarylpyrimidines were designed as non-nucleoside anti-HIV inhibitors targeting reverse transcriptase by a fragment-based replacement strategy with the purpose of improving the druggability. Hopping five- or six-membered heterocycle groups on the biphenyl moiety as bioisosterism for intrinsically cyanophenyl gave 23 derivatives. All of these compounds possessed excellent HIV-1 inhibitory activity in the nanomolar range. Among them, <b>12g</b> with a 4-pyridine group displayed excellent inhibitory activity toward WT and mutant HIV virus possessing significant selectivity. Moreover, this compound exhibited a decent improvement in druggability than etravirine and rilpivirine: (1) The hydrochloric acid salt of <b>12g</b> exhibited significantly improved water solubility in different pH conditions. (2) <b>12g</b> did not show apparent CYP enzymatic inhibitory activity or acute toxicity. (3) Excellent oral bioavailability was also revealed (<i>F</i> = 126%, rats) in <b>12g</b>. Collectively, these novel heteroaromatic-biphenyl-DAPYs represent promising drug candidates for HIV clinical therapy.