反应详情

9.81 g (50 mmoles) of methyl N-(4-nitrophenyl)carbamate, 6.9 g (50 mmoles) of 4-nitroaniline, 140 ml of xylene and 11.8 g (about 50 mmoles) of Genamin CS 302 D (a mixture of N,N-dimethyl-C10-18 alkylamines sold by the firm Hoechst AG) are introduced into a flask equipped with a reflux condenser, and the mixture is boiled. The yellow crystals of the end-product appear already in the 3rd minute of boiling, and the amount of the crystalline precipitate rapidly increases. After 0.5 hours of boiling the thick, orange crystal suspension is filtered in vacuo when hot, the filter cake is washed twich with 20 ml of hot xylene, each, and then with acetone, finally the product is dried in vacuo. 12.78 g (85.2%) of N,N'-bis(4-nitrophenyl)-urea are obtained. The product is uniform when examined by layer chromatography utilizing a 3:1 mixture of n-hexane and acetone as solvent, and the chromatographic appearance of the product is identical with that of the authentic sample.

1. additionare introduced into a flask
2. customequipped with a reflux condenser
3. temperaturethe amount of the crystalline precipitate rapidly increases
4. filtrationthe thick, orange crystal suspension is filtered in vacuo when hot
5. washthe filter cake is washed twich with 20 ml of hot xylene
6. dry with materialeach, and then with acetone, finally the product is dried in vacuo