反应详情

Ethyl 3-amino-4-methylaminobenzoate (24.1 g, 124 mmol) in the Step 1-1-3 was dissolved in formic acid (200 ml), and the solution was heated under reflux for 2 hours. After being cooled by ice, the solution was neutralized with a 25% ammonia water. The solution was subjected to extraction with chloroform, and the extract was dried over anhydrous magnesium sulfate and then concentrated. The concentrate was purified by silica gel column chromatography (chloroform:methanol=20:1) to give the title compound (26.1 g, quantitative) as a light-purple powder.

1. temperaturethe solution was heated
2. temperatureunder reflux for 2 hours
3. temperatureAfter being cooled by ice
4. extractionThe solution was subjected to extraction with chloroform
5. dry with materialthe extract was dried over anhydrous magnesium sulfate
6. concentrationconcentrated
7. customThe concentrate was purified by silica gel column chromatography (chloroform:methanol=20:1)