Benzeneacetic acid, alpha-hydroxy-, 5,5a,13,13a-tetrahydro-7,15-dioxo-8H,16H-7a,15a-epitetrathio-7H,15H-bisoxepino(3',4':4,5)pyrrolo(1,2-a:1',2'-d)pyrazine-5,13-diyl ester, (5S-(5alpha(S*),5aalpha,7abeta,13alpha(S*),13aalpha,15abeta))-