Methyl 1,2,3,9b-tetrahydro-4λ4-benzo[c]thieno[2,1-e]isothiazole-8-carboxylate 4-oxideMethyl 1,2,3,9b-tetrahydro-4λ4-benzo[c]thieno[2,1-e]isothiazole-8-carboxylate 4-oxide 95%