反应详情

A solution of 3-methyl-4-oxo-4H,5H-[1]benzothiopyrano[4,3-b]pyran-2-carbonitrile (0.255 g, 1 mmole, described in Example 6) in 2.5 N aqueous sodium hydroxide (10 ml) and methanol (5 ml) is refluxed overnight. The solution is acidified with hydrochloric acid. The precipitate is collected and dissolved in 1 N aqueous sodium hydroxide. The solution is washed with chloroform and acidified with hydrochloric acid. The precipitate is collected and crystallized from methanol to give the title compound (0.070 g), mp 275°-277° C.

1. customThe precipitate is collected
2. dissolutiondissolved in 1 N aqueous sodium hydroxide
3. washThe solution is washed with chloroform
4. customThe precipitate is collected
5. customcrystallized from methanol