Hydrochloric Acid → 3-Acetyl-2,5-dihydro-4-hydroxy-5-methyl-1,2-thiazino[5,6-b]indole-1,1-dioxide

Participants

Reaction Steps

10 gm (34 millimols) of 2-acetonyl-4-methyl-2H-isothiazolo [4,5-b]-indole-3(4H)-one-1,1-dioxide were added to a methanolic sodium methylate solution [1.6 gm of sodium (0.107 gm-atoms) in 60 ml of anhydrous methanol]. After half an hour of stirring at room temperature, the mixture was heated for 45 minutes on an oil bath at 60° C. Subsequently, the reaction mixture was cooled on an ice bath and acidified with 1 N hydrochloric acid to a pH of 3-4. The precipitate formed thereby was filtered off, washed with ice water, dried and recrystallized from ethylene chloride, yielding 6.4 gm (64% of theory) of 3-acetyl-2,5-dihydro-4-hydroxy-5-methyl-1,2-thiazino[5,6-b ]-indole-1,1-dioxide. M.p.: 210°-211° C.;

Provenance & Evidence