“…These additional binding contacts improved the potency of R221239 against a panel of HIV-1-resistant strains bearing the V106A, Y188L, and F227C mutations ( Figure 2). 18 In an effort to more fully explore the structure-activity relationships (SARs) of the diarylpyrimidine (DAPY)-based NNRTIs (exemplified by 6, etravirine, ETV) and potentially attenuate the resistance of the existing mutants, a further investigation of the interactions of the DAPYs with the solvent-exposed region of RT resulted in the identification of piperidine-linked aminopyrimidine and thiophene [3,2-d]pyrimidine derivatives, which exhibited broad-spectrum activity with low (single-digit) nanomolar EC 50 values toward a panel of WT, single-mutant, and double-mutant HIV-1 strains. [19][20][21][22][23][24][25] Compared with 6, piperidine-linked aminopyrimidine derivatives 7 and 8 possess broad potency against…”