Cyclic sulfone-3-carboxamides are effective P2-1igands for HIV-1 protease inhibitors. Incorporation of 3S-tetrahydro-2H-thiopyrancarboxamide-l, l-dioxide in the hydroxyethylamine series resulted in inhibitor 14 (IC50=9 nM, CIC95=200 nM) with improved potency compared to its corresponding urethane derivative 18 (IC50=2.0 μM).