37895-65-1 4,4-Dimethyl-1,7-dioxa-2,6-diaza-7a-thia-3H,5H-benzo(cd)pentalene 6H-3.lambda.4-(1,2,5)Oxathiazolo(4,3,2-hi)(2,1,3)benzoxathiazole, 7,8-dihydro-7,7-dimethyl- HEP-I