(2S)-N-((1S,2R)-3-{(1S,4S,6S)-3-Aza-4-[N-(tert-butyl)carbamoyl]bicyclo[4.4.0]dec-3-yl}-2-hydroxy-1-benzylpropyl)-2-(acetylamino)-3-methylbutanamide AIDS-059197 AIDS059197 Ac-Val-Phe-psi [CH(O)CH2]-DIQ-NH-tBu deriv.