反应详情

A mixture of 9.22 grams (0.04 mole) of 4-bromo-2-methylphenyl isocyanate, 5.78 grams (0.04 mole) of ethyl nitroacetate, 6.01 grams (0.04 mole) of anhydrous potassium carbonate and 90 milliliters of benzene was stirred and heated under reflux for 3 hours then cooled and stirred at room temperature for a period of about 16 hours. The precipitated material was filtered off and thoroughly triturated with 200 milliliters of ice water, filtering to remove a precipitate which was discarded. Chilling and acidification of the filtrate with concentrated HCl caused precipitation of a yellow-white solid which was collected, water-washed and air-dried. Recrystallization from benzene-cyclohexane (3:1) gave 3.38 grams (0.01 mole) of ethyl 3-[(4-bromo-2-methylphenyl)amino]-2-nitro-3-oxopropanoate as white crystals having a melting point of 126° C.-129° C. Elemental analysis of the product indicated the following:

1. temperatureheated
2. temperatureunder reflux for 3 hours
3. temperaturethen cooled
4. stirringstirred at room temperature for a period of about 16 hours
5. filtrationThe precipitated material was filtered off
6. customthoroughly triturated with 200 milliliters of ice water
7. filtrationfiltering
8. customto remove a precipitate which
9. temperatureChilling
10. customprecipitation of a yellow-white solid which
11. customwas collected
12. washwater-washed
13. customair-dried
14. customRecrystallization from benzene-cyclohexane (3:1)