Ethanol → 3-(2-hydroxy-3-morpholinopropyl)-1H-2,3-benzothiazin-4(3H)-one 2,2-dioxide

Participants

Reaction Conditions

Reaction Steps

In dry ethanol (10 mL) was dissolved metallic sodium (23 mg, 1 mmol.), and to the solution was added 1H-2,3-benzothiazin-4(3H)-one 2,2-dioxide (197 mg, 1 mmol.). The mixture was stirred at 50° C. for 30 min. To the reaction solution was added 1-chloro-3-morpholino-2-propanol (198 mg, 1.1 mmol.). The mixture was then heated for 6 hours under refluxing. The reaction liquid was placed under reduced pressure to distill the solvent off. The resulting residue was treated with 1N hydrochloric acid and ethyl acetate. The aqueous layer was taken out, and made basic by addition of potassium carbonate. The oil precipitated and was extracted with ethyl acetate. The ethyl acetate portion was washed with an aqueous saturated sodium chloride solution, and then dried over anhydrous sodium sulfate. The dried ethyl acetate portion was placed under reduced pressure to distill the solvent off. The resulting residue was treated by silica gel column chromatography (chloroform/methanol=40/1) to give 3-(2-hydroxy-3-morpholinopropyl)-1H-2,3-benzothiazin-4(3H)-one 2,2-dioxide (215 mg, yield 63%) as a colorless oil, and 3-(2 -ethoxy3-morpholinopropyl)-1H-2,3-benzothiazin-4(3H)-one 2,2-dioxide (70 mg, yield 20%) as an colorless oil.

Provenance & Evidence