AIDS-005398 AIDS005398 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]-N-benzyl-2-thiazolidineacetamide]