Acetic acid, ((2-((bromoacetyl)amino)ethyl)thio)-, 6-ethenyldecahydro-5-hydroxy-4,6,9,10-tetramethyl-1-oxo-3a,9-propano-3aH-cyclopentacycloocten-8-yl ester, (3aS-(3aalpha,4beta,5alpha,6alpha,8beta,9beta,9abeta,10S*))-