Pyridine → Methyl N-(oxomethylidene)phenylalaninate

HRID 1976535Notes

Reaction equation

HRID 1976535 reaction equation
Cl.[CH3:2][O:3][C:4](=[O:14])[C@H:5]([CH2:7][C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=1)[NH2:6].N1C=CC=CC=1.[C:21](Cl)(Cl)=[O:22].C1(C)C=CC=CC=1>ClCCl>[N:6]([C@@H:5]([CH2:7][C:8]1[CH:13]=[CH:12][CH:11]=[CH:10][CH:9]=1)[C:4]([O:3][CH3:2])=[O:14])=[C:21]=[O:22]

Participants

6

Reactant 4

HCID 1049PyridineHCID 1140TolueneHCID 6371PhosgeneHCID 75736Methyl L-phenylalaninate hydrochloride

Product 1

HCID 1514293Methyl N-(oxomethylidene)phenylalaninate

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Conditions

Temperature
0 °C

Procedure

A well-stirred cold mixture (0° C.) of phenylalanine methyl ester hydrochloride (200 mg), anhydrous dichloromethane (3 ml), and anhydrous pyridine (295 μl, 4 eq.) was stirred for 15 min. A 2M phosgene solution in toluene (455 μl, 0.98 eq.) was added over 30 sec. followed by stirring for 2 h at 0° C. The reaction mixture was poured into dichloromethane washed with cold IN hydrochloric acid then ice water. Each aqueous layer was back extracted once with dichloromethane. The combined organic layer was washed once with brine, dried over anhydrous magnesium sulfate and concentrated. Distillation under vacuum afforded methyl (S)-2-isocyanato-3-phenylpropanoate (125 mg).

Workup

  1. washwashed with cold IN hydrochloric acid
  2. extractionEach aqueous layer was back extracted once with dichloromethane
  3. washThe combined organic layer was washed once with brine
  4. dry with materialdried over anhydrous magnesium sulfate
  5. concentrationconcentrated
  6. distillationDistillation under vacuum

Sources & evidence

ORD record
ord-6b54892e9b914fa993a77915ba2e691d
Source dataset
uspto-grants-2001_05
Patent number
US06228842B1

Reaction notes

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