Thiazol-5-ylmethyl ((2S,3S,5S)-5-Amino-3-((tert-butyldimethylsilyl)oxy)-1,6-diphenylhexan-2-yl)carbamate is an intermediate in synthesizing Bis(thiazol-5-yl-methyl)[carbonylbis[imino[(2S,3S,5S)-3-hydroxy-1,6-diphenylhexane-5,2-diyl]]]dicarbamate (R535035). Ritonavir Impurity P is derived from 2S,3S,5S-5-Amino-2-[N-[[(5-thiozolyl)methoxy]carbonyl]amino]-1,6-diphenyl-3-hydroxyhexane (A630525), which is an intermediate in the synthesis of Ritonavir (R535000), a selective HIV protease inhibitor.