反应详情

2,3-Dimethoxy-6-nitrobenzoic acid (l, 180.0 g, 0.792 mole) was dissolved in triethyl orthoformate (466.2 g, 3.14 mole) optionally containing dimethylformamide (4 mL) and the mixture was heated to reflux for one hour. The solvent was removed in vacuo, the residue was extracted with chloroform (2 L) and the organic layer was dried over magnesium sulfate. Removal of the solvent in vacuo gave the product as a pale brown oil which crystallized upon standing at room temperature, 202 g (100%, m.p. 70°-72° C.). This material could be recrystallized from isopropanol but was generally reacted in the next step without additional purification.

1. temperaturethe mixture was heated
2. temperatureto reflux for one hour
3. customThe solvent was removed in vacuo
4. extractionthe residue was extracted with chloroform (2 L)
5. dry with materialthe organic layer was dried over magnesium sulfate
6. customRemoval of the solvent in vacuo