127311-83-5 3a-Methyl-4,7-hexahydroepoxybenzo(c)thiophene-1,3-dione (3a-alpha,4-beta,7-beta,7a-alpha)- 4,7-Epoxybenzo(c)thiophene-1,3-dione, hexahydro-3a-methyl-, (3a-alpha,4-beta,7-beta,7a-alpha)-