2-Heptenoic acid, 4-[[[(3R,6S,8aS)-hexahydro-5-oxo-6-[[(phenylmethoxy)carbonyl]amino]-5H-thiazolo[3,2-a]pyridin-3-yl]carbonyl]amino]-7-amino-7-oxo-, ethyl ester, (2E,4S)- AIDS-121701 AIDS121701