Phosgene → 7-isocyanato-4-methyl-2H-chromen-2-one

HRID 2061377Notes

Reaction equation

HRID 2061377 reaction equation
[C:1](Cl)(Cl)=[O:2].[NH2:5][C:6]1[CH:15]=[C:14]2[C:9]([C:10]([CH3:17])=[CH:11][C:12](=[O:16])[O:13]2)=[CH:8][CH:7]=1>C1(C)C=CC=CC=1.O1CCOCC1>[N:5]([C:6]1[CH:15]=[C:14]2[C:9]([C:10]([CH3:17])=[CH:11][C:12](=[O:16])[O:13]2)=[CH:8][CH:7]=1)=[C:1]=[O:2]

Participants

5

Reactant 2

HCID 6371PhosgeneHCID 922497-Amino-4-methylcoumarin

Product 1

HCID 583781007-isocyanato-4-methyl-2H-chromen-2-oneYield 25%

Reagents, catalysts & solvents 2

HCID 1140TolueneSolventHCID 312751,4-DioxaneSolvent

Conditions

Temperature
100 °C

Procedure

A 200-mL three-neck flask fitted with a dry ice condenser and magnetic stirrer was charged with a solution of 20% phosgene in toluene solution (2.0 mL) and dioxane (80 mL). To this mixture was added 7-amino-4-methyl-2H-chromen-2-one (2.00 g, 11.4 mmol). The mixture was stirred at 100° C. for 12 h. The initial yellow colour disappeared and a white solid precipitated. An additional 20% phosgene in toluene solution (7.0 mL) was added and the mixture heated for an additional 5 h, at which time the solution cleared. Excess phosgene and traces of HCl was removed by bubbling nitrogen gas through the solution. The cloudy solution was filtered to remove unreacted 7-amino-4-methyl-2H-chromen-2-one and concentrated to give 76 (0.5 g, 25%) as a white solid. H1 NMR (500 MHz, CDCl3): δ=7.50 (1H, d, J=7.40 Hz, ArH), 7.46 (2H, s, ArH), 6.20 (1H, s, ArH), 2.35 (3H, s, CH3): ir (CH2CL2) 2314 (N═C═O), 1726 and 1615 cm−1.

Workup

  1. customA 200-mL three-neck flask fitted with a dry ice condenser and magnetic stirrer
  2. customa white solid precipitated
  3. additionAn additional 20% phosgene in toluene solution (7.0 mL) was added
  4. temperaturethe mixture heated for an additional 5 h, at which time the solution
  5. customExcess phosgene and traces of HCl was removed
  6. customby bubbling nitrogen gas through the solution
  7. filtrationThe cloudy solution was filtered
  8. customto remove unreacted 7-amino-4-methyl-2H-chromen-2-one
  9. concentrationconcentrated

Sources & evidence

ORD record
ord-4cfcdfbea8074b608028271eb26a4f07
Source dataset
uspto-grants-2012_10
Patent number
US08283340B2

Reaction notes

Loading…