AIDS-005387 AIDS005387 Penicillin Et(NH)2 dimer [2R-[2.alpha.(R*),4.-beta.-]]-4,4'-[1,2-Ethanediylbis[aminocarbonyl]]-bis[5,5-dimethyl-.alpha.-[(2-pyridinylacetyl)amino]-2-thiazolidineacetic acid, methyl ester]