Phosgene → 2-Methyl-4-nitrophenyl isocyanate

Temperature

0 °C

2-Methyl-4-nitroaniline (35.0 g, 230 mmol) was dissolved in ethyl acetate (400 ml) and cooled to 0° C. Phosgene (180 ml, 20% in toluene) was added drop wise over 30 min, precipitation of a white salt followed instantly. After the last addition the temperature was allowed to slowly rise to room temperature, and then the reaction mixture was brought to reflux (˜100° C.). It was refluxed for 2 h 30 min, after which 200 ml of solvent was distilled off before the temperature was lowered to 80° C. and phosgene (140 ml, 20% in toluene) was added drop wise. After the last addition the reaction solution was refluxed for 3 hours, allowed to cool to room temperature and concentrated to dryness. The brown/yellow material was dissolved in diethyl ether (250 ml), filtered and concentrated to give a pale brown powder (36 g, 88%).

1. customprecipitation of a white salt
2. additionAfter the last addition the temperature
3. customto slowly rise to room temperature
4. temperatureto reflux (˜100° C.)
5. temperatureIt was refluxed for 2 h 30 min
6. distillationafter which 200 ml of solvent was distilled off before the temperature
7. customwas lowered to 80° C.
8. additionphosgene (140 ml, 20% in toluene) was added drop wise
9. additionAfter the last addition the reaction solution
10. temperaturewas refluxed for 3 hours
11. temperatureto cool to room temperature
12. concentrationconcentrated to dryness
13. dissolutionThe brown/yellow material was dissolved in diethyl ether (250 ml)
14. filtrationfiltered
15. concentrationconcentrated

ORD record

ord-219224ee46ec4191a936c6f98f3243a6

Source dataset

uspto-grants-2016_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09272056B2