Hydrochloric Acid → HCID 14234716, compound

Participants

Reaction Steps

Methyl 3,4-dihydro-2-isopropyl-3-thioxo-2H-1,4-benzothiazine-4-acetate (20.65 g) was dissolved in methanol-dioxane (1:2, v/v, 210 ml), to which 2N-NaOH (70 ml) was added dropwise with stirring. The mixture was stirred at room temperature for further 2 hours, diluted with water and acidified with hydrochloric acid. The crystalline precipitate was collected by filtration and recrystallized from 2-propanol-water to give 3,4-dihydro-2-isopropyl-3-thioxo-2H-1,4-benzothiazine-4-acetic acid as yellow prism. Yield was 18.0 g (91.5%). mp 175°-176° C.

Provenance & Evidence