反应详情

The carboxylic acid group of the compound of Example 2 (ethyl 4-oxochromane-2-carboxylate) was treated with a metallic hydroxide base in ethanol, and then the aqueous layer was treated with an acid to form the free acid, which was washed with water and then dried to yield 3 g of 4-oxo-chromane-2-carboxylic acid.

1. additionthe aqueous layer was treated with an acid
2. customto form the free acid, which
3. washwas washed with water
4. customdried