反应详情

2-(4-Hydroxy-5-oxo-1,3,6-cycloheptatrien-1-ylamino)-2-butenedioic acid diethyl ester (100 g, described in Example 1) is added in portions over 5 minutes to diphenyl ether (1000 ml) at reflux temperature. The solution is refluxed for 25 minutes and cooled to room temperature. Hexane (2000 ml) is added and the crystalline precipitate is collected. The precipitate is crystallized from acetic acid to obtain crystals of the title compound, mp > 300° C. and ν max 3270, 3170, 3100, 1740, 1620 and 1575 cm-1.

1. temperatureat reflux temperature
2. temperatureThe solution is refluxed for 25 minutes
3. customthe crystalline precipitate is collected
4. customThe precipitate is crystallized from acetic acid