Hydrochloric Acid → HCID 59718797, compound

Participants

Reaction Steps

4M sodium hydroxide solution (15.2 mL, 60.8 mM) was added to a methanol (30 mL) solution of ethyl 1-cyclohexylmethyl-2-oxo-1,5,7,8,tetrahydro-2H-thiopyrano[4,3-b]pyridine-3-carboxylate (AA08, 8.16 g, 24.3 mmol), which had been obtained in Example 8, at room temperature, and the mixture was heated and refluxed for 30 minutes. The reaction mixture was diluted with water (100 mL) and washed with ether (100 mL). 5M hydrochloric acid (13 mL, 65 mmol) was added to the water layer, the precipitated crystal was separated by filtration and washed with water, and the brown crystal of 1-cyclohexylmethyl-2-oxo-1,5,7,8,tetrahydro-2H-thiopyrano[4,3-b]pyridine-3-carboxylic acid (6.78 g) was obtained. The crystal was recrystallized from ethanol-water to give light brown crystalline powder (AA09, 6.30 g, 84.3%).

Provenance & Evidence