4-[[[3-[2-[[(1,1-Dimethylethyl)amino]carbonyl]-1-piperidinyl]-2-hydroxypropyl]amino]carbonyl]-5,5-dimethyl-.alpha.-[(phenylacetyl)amino]-N-(phenylmethyl)-2-thiazolidineacetamide, [2R-[2.alpha.(R*),4. AIDS-006798 AIDS006798 Penicillin, 1Piperid-OHPrNH2 analog