AIDS-005480 AIDS005480 Penicillin deriv. [2R-[2.alpha.(R*),4.beta.(R)]]-5,5-Dimethyl-.alpha.-[(phenylacetyl)amino]-N-(phenylmethyl)-4-[[[1-(2-phenyl-1-methyl)ethyl]amino]carbonyl]-2-thiazolidineacetamide