Download PDF Opens in a new window. Article suggestions will be shown in a dialog on return to ScienceDirect. ... Please enable JavaScript to use all the features on this page. ... The HIV protease inhibitor ABT-378 (Lopinavir) has a 2,6-dimethylphenoxyacetyl group in the P-2′ position. Analogues in which this group is replaced with various substituted phenyl or heteroaryl groups were synthesized and the structure–activity relationships explored.