反应详情

A mixture of 8-methoxy-5-nitro-3,4-dihydro-2H-1-benzopyran-3-carboxylic acid ethyl ester (5.8 g, 21 mmol) in ethanol (150 mL) and 2 M NaOH (15 mL) was heated to reflux for 30 min The solvent was evaporated in vacuo the residue dissolved in water. Acidification to pH 2 and extraction with ethyl acetate followed by evaporation of the solvent in vacuo gave 4.9 g (94% yield) of the title compound: mp 181-183° C.; EIMS (70 eV) m/z (relative intensity) 253 (55, M+).

1. temperaturewas heated
2. temperatureto reflux for 30 min The solvent
3. customwas evaporated in vacuo the residue
4. dissolutiondissolved in water
5. extractionAcidification to pH 2 and extraction with ethyl acetate
6. customfollowed by evaporation of the solvent in vacuo