Hydrochloric Acid → 4-Isocyanato-2-(trifluoromethyl)benzonitrile

5-Amino-2-cyanobenzotrifluoride (0.07 g, 0.36 mmol) was dissolved in ethyl acetate (2 mL) and dry hydrogen chloride in ethyl acetate (3.5 M, 5.5 mL) was added. After 15 min the solution was concentrated to dryness and co-evaporated three times from toluene (3×5 mL). The residue was added toluene (2.5 mL) and flushed with nitrogen for about 10 min. before diphosgene (0.43 mL) was added. Then the mixture was gently refluxed for 1 hour under a nitrogen atmosphere. The mixture was cooled and concentrated to dryness in vacuo and then co-evaporated twice from toluene to remove excessive diphosgene to afford 4-cyano-3-trifluoromethylphenyl isocyanate.

1. concentrationAfter 15 min the solution was concentrated to dryness and co-evaporated three times from toluene (3×5 mL)
2. additionThe residue was added toluene (2.5 mL)
3. customflushed with nitrogen for about 10 min. before diphosgene (0.43 mL)
4. additionwas added
5. temperatureThen the mixture was gently refluxed for 1 hour under a nitrogen atmosphere
6. temperatureThe mixture was cooled
7. concentrationconcentrated to dryness in vacuo
8. customto remove excessive diphosgene

ORD record

ord-4824baeae6124bd5a64ee32d9966e1f5

Source dataset

uspto-grants-2005_10

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06953812B2