Sodium Carbonate → 5-Methyl-6-ethoxycarbonyl-8-chlorothiochroman-4-one

Participants

Reaction Steps

47.7 Grams (157 mmol) of 3-(2-chloro-4-ethoxycarbonyl-5-methylphenylthio)propionic acid was added to 167 g of 20 wt % P2O5 -containing polyphosphoric acid heated at 80~85° C., and then the mixture was stirred under heat for 1 hour and 20 minutes. After allowed to cool to room temperature, the reaction mixture was gradually added to a mixture of 191 g (1.80 mol) of sodium carbonate and ice, and the mixture was stirred at room temperature until the sodium carbonate was almost dissolved. The mixture was extracted with ethyl acetate twice, and the extract was washed with a sodium carbonate aqueous solution twice, with water twice and with a saturated sodium chloride aqueous solution once, and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure to give 41.3 g (yield 85%) of 8-chloro-6-ethoxycarbonyl-5-methylthiochroman-4-one.

Provenance & Evidence