Sulfuric Acid → HCID 19027004, compound
Reaction equation
O[CH:2]1[C:7]2[CH:8]=[CH:9][S:10][C:6]=2[S:5](=[O:12])(=[O:11])[NH:4][CH2:3]1.S(=O)(=O)(O)[OH:14].[C:18](#[N:20])[CH3:19]>>[C:18]([NH:20][CH:2]1[C:7]2[CH:8]=[CH:9][S:10][C:6]=2[S:5](=[O:12])(=[O:11])[NH:4][CH2:3]1)(=[O:14])[CH3:19]Participants
4
Procedure
A solution of 3,4-dihydro-4-hydroxy-2H-thieno[3,2-e]-1,2-thiazine-1,1-dioxide (10.26 g, 0.05 mol) in acetonitrile (100 ml) was cooled to 0° C. Then concentrated sulfuric acid (26.6 ml, 0.50 mol) was added dropwise over 1/2 hr. at 0° to 5° C. The reaction mixture was stirred for 1/2 hr. at 5° C. and for 4 hrs. at ambient temperature. The resulting solution was poured into ice water (200 ml). A pale beige solid precipitated and was filtered and dried. Wt. was 10.2 g. Yield 83%.