Synthesis, Antiviral Activity, and Structure–Activity Relationship of 1,3‐Benzodioxolyl Pyrrole‐Based Entry Inhibitors Targeting the Phe43 Cavity in HIV‐1 gp120

The pathway by which HIV‐1 enters host cells is a prime target for novel drug discovery because of its critical role in the life cycle of HIV‐1. The HIV‐1 envelope glycoprotein gp120 plays an important role in initiating virus entry by targeting the primary cell receptor CD4. We explored the substitution of bulky molecular groups in region I in the NBD class of entry inhibitors. Previous attempts at bulky substituents in that region abolished antiviral activity, even though the binding site is hydrophobic. We synthesized a series of entry inhibitors containing the 1,3‐benzodioxolyl moiety or its bioisostere, 2,1,3‐benzothiadiazole. The introduction of the bulkier groups was well tolerated, and despite only minor improvements in antiviral activity, the selectivity index of these compounds improved significantly.