Phosgene → Methyl (3-chloro-4-hydroxyphenyl)carbamate

HRID 1580524Notes

Reaction equation

HRID 1580524 reaction equation
[NH2:1][C:2]1[CH:7]=[CH:6][C:5]([OH:8])=[C:4]([Cl:9])[CH:3]=1.[CH2:10]([O:12][C:13](=[O:15])C)C.C(Cl)(Cl)=O>C1C=CC=CC=1>[Cl:9][C:4]1[CH:3]=[C:2]([CH:7]=[CH:6][C:5]=1[OH:8])[NH:1][C:13](=[O:15])[O:12][CH3:10]

Participants

5

Reactant 3

HCID 6371Phosgene2×HCID 8857Ethyl AcetateHCID 775784-Amino-2-chlorophenol

Product 1

HCID 18932212Methyl (3-chloro-4-hydroxyphenyl)carbamate

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent

Conditions

Temperature
40 °C

Procedure

Powdered 4-amino-2-chlorophenol (210 grams, 1.46 moles) is added to a dry ethylacetate solution (2100 ml.) of phosgene (210 grams, 2.05 moles) and the mixture is stirred at 0°C. to 10°C. Slowly the reaction mixture is raised to reflux temperature after 1 hour. Further phosgene (20 grams) is passed through the solution during a one-half hour period, then the mixture is heated under reflux during another 30 minute period, cooled to 40°C., and rapidly filtered. The filtrate is evaporated under reduced pressure to a volume of 900 ml. An infrared spectrum of this oil has a peak at 2260 cm.-1 (N=C=O). The isocyanate solution is added to methanol (1.8 liters) with stirring, and the reaction is brought to reflux for 16 hours, then set aside at 20°C. for 48 hours. Evaporation of the reaction mixture affords a viscous oil. Addition of benzene (2 × 300 ml.) followed by evaporation causes the oil to solidify. The crude solid is vacuum dried, melting point 96°C. to 98°C., 250.5 grams (86%). Crystallization of a 5 gram sample from benzene (trace n-hexane) affords crystals, melting point 104°C. to 105°C., 2.76 grams (47%).

Workup

  1. temperatureSlowly the reaction mixture is raised
  2. temperatureto reflux temperature after 1 hour
  3. temperaturethe mixture is heated
  4. temperatureunder reflux during another 30 minute period
  5. filtrationrapidly filtered
  6. customThe filtrate is evaporated under reduced pressure to a volume of 900 ml
  7. additionThe isocyanate solution is added to methanol (1.8 liters)
  8. stirringwith stirring
  9. temperatureto reflux for 16 hours
  10. customEvaporation of the reaction mixture
  11. customaffords a viscous oil
  12. customfollowed by evaporation
  13. customdried
  14. customCrystallization of a 5 gram sample from benzene (trace n-hexane)
  15. customaffords crystals, melting point 104°C. to 105°C., 2.76 grams (47%)

Sources & evidence

ORD record
ord-1b544e7d8d38446cad090e3d8228b401
Source dataset
uspto-grants-1976_01
Patent number
US03933470

Reaction notes

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