1,3,3a,4,9,9a-Hexahydrothieno(3,4-b)quinoxaline 2-oxide 121431-71-8 Hexahydro-1,3,3a,4,9,9a thieno(3,4-b)quinoxaline oxyde-2 [French] Thieno(3,4-b)quinoxaline, 1,3,3a,4,9,9a-hexahydro-, 2-oxide