4-Thiazolidinecarboxamide, N-[3-(4-morpholinyl)-1-oxopropyl]-3-(1-naphthalenyl)-L-alanyl-L-valyl-(.alpha.S,.beta.S)-.beta.-amino-.alpha.-hydroxybenzenebutanoyl-N-(1,1-dimethylethyl)-, (4R)- AIDS-029859 AIDS029859