FURO[3',4':6,7]NAPHTHO[2,3-D]-1,3-DIOXOL-6(5AH)-ONE, 9-(ETHYLTHIO)-5,8,8A,9-TETRAHYDRO-5-(3,4,5-TRIMETHOXYPHENYL)-, [5R-(5A,5ASS,8AA,9SS)]-