反应详情

温度

2.5 °C

A mixture of 4-amino-3-nitrobenzonitrile (63.3 g, 388 mmol) in 1,4-dioxane (600 mL) and anhydrous ethanol (600 mL) was cooled in an ice water bath to 0-5° C. and treated with gaseous HCl for 1.5 h. The reaction mixture was tightly sealed and allowed to warm up to room temperature with stirring for 18 h. The flask was then carefully unsealed and the reaction mixture was diluted with anhydrous diethyl ether (about 2.4 L) until a cloudy solution was obtained. A minimum amount of absolute ethanol required to give a clear solution was then added, and the resulting solution stirred until crystals of 4-amino-3-nitro-benzimidic acid ethyl ester were observed. Ether was then cautiously added to complete the crystallization process and the suspension was allowed to stand for about 30 minutes. The crystals were filtered and washed with dry diethyl ether, then allowed to dry under aspirator vacuum. The crystals were dried in vacuo to give 4-amino-3-nitro-benzimidic acid ethyl ester hydrochloride (84.6 g) as off-white crystals.

1. customThe reaction mixture was tightly sealed
2. temperatureto warm up to room temperature
3. customwas obtained
4. customto give a clear solution
5. additionwas then added
6. waitto stand for about 30 minutes
7. filtrationThe crystals were filtered
8. washwashed with dry diethyl ether
9. customto dry under aspirator vacuum
10. customThe crystals were dried in vacuo