Hydrochloric Acid → HCID 22934786, compound

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Reaction Steps

2-Chloro-4,7-dihydro-1,3-benzothiazol-6(5H)-one (Helv. Cim. Acta., vol. 77, p. 1256 (1994)) (2.0 g) was dissolved in methanol (100 mL), and to the solution were added ammonium acetate (8.2 g) and sodium cyanoborohydride (4.0 g), followed by heating under reflux for 20 hours. Hydrochloric acid was added to the reaction mixture, to thereby decompose excess sodium cyanoborohydride, and the solvent was distilled away under reduced pressure. A 1N sodium hydroxide solution was added to the residue, to thereby make the mixture alkaline. The mixture was extracted with methylene chloride. The organic layer was dried over anhydrous magnesium sulfate, and the solvent was distilled away under reduced pressure, to thereby give a pale-yellow oily matter. This oily matter was dissolved in methanol (50 mL), and to the solution were added aqueous formaldehyde (4.29 g) and sodium cyanoborohydride (3.49 g), followed by stirring at room temperature for 12 hours. The solvent was distilled away under reduced pressure, and methylene chloride was added to the residue. The thus-obtained mixture was washed with saturated sodium hydrogencarbonate, and the organic layer was dried over anhydrous magnesium sulfate. The solvent was distilled away under reduced pressure, and the residue was purified by silica gel column chromatography (methylene chloride:methanol=10:1), to thereby give the title compound (740 mg).

Provenance & Evidence