反应详情

A solution of the benzylidenerhodanine of Example 10 in 46 ml. of 15% NaOH is refluxed for 0.75 hour, cooled, and poured into dilute HCl. The resulting tan precipitate is collected and air-dried. Two recrystallizations from methanol (charcoal) give 8-methoxy-1-oxo-1H-2-benzothiopyran-3-carboxylic acid as a pale yellow solid, m.p. 275° (dec.).

1. temperaturecooled
2. customThe resulting tan precipitate is collected
3. customair-dried
4. customTwo recrystallizations from methanol (charcoal)