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-6c4402033c2c455e9322a6feb27fdbc0

Source dataset

uspto-grants-2003_05

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06562807B2