Hydrochloric Acid → HCID 21440743, compound

Participants

Reaction Steps

A solution of the 5-(2-carboxy-5-methoxybenzylidene)rhodanine of Example 4 in dilute sodium hydroxide (35 ml. of 20% NaOH + 11 ml. H2O) is refluxed for one hour and then poured into dilute HCl. The resulting pale yellow solid is collected and recrystallized repeatedly from ethanol to give 6-methoxy-1-oxo-1H-2-benzothiopyran-3-carboxylic acid as pale yellow crystals, m.p. 278°-279°.

Provenance & Evidence