Hydrochloric Acid → 6-Carboxy-8-chloro-5-methylthiochroman-4-one

Participants

Reaction Steps

2.0 Grams (7.0 mmol) of 8-chloro-6-ethoxycarbonyl-5-methylthiochroman-4-one was dissolved in 10 ml of acetic acid, and 10 ml of a 4N hydrochloric acid aqueous solution was added. The mixture was refluxed under heat for 5 hours. After allowed to cool to room temperature, the reaction mixture was diluted with about 100 ml of water, and a precipitated solid was extracted with ethyl acetate. A carboxylic acid component was extracted from an organic layer with a saturated sodium hydrogencarbonate aqueous solution, and an aqueous layer was neutralized and acidified with a 5 wt % hydrochloric acid aqueous solution. A precipitated solid was extracted with ethyl acetate, and an organic layer was washed with a saturated sodium chloride aqueous solution and dried over anhydrous sodium sulfate. The solvent was distilled off to give 1.6 g (yield 90%) of 6-carboxy-8-chloro-5-methylthiochroman-4-one in the form of a white solid.

Provenance & Evidence