Ethyl chloroformate → EtOCO-D,L-Phe(alphaMe)-OH
Reaction equation
[NH2:1][C:2]([CH3:13])([C:10]([OH:12])=[O:11])[CH2:3][C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1.C/C(/O[Si](C)(C)C)=N\[Si](C)(C)C.C(N(CC)C(C)C)(C)C.Cl[C:36]([O:38][CH2:39][CH3:40])=[O:37]>O1CCCC1.O>[CH2:39]([O:38][C:36]([NH:1][C:2]([CH3:13])([C:10]([OH:12])=[O:11])[CH2:3][C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1)=[O:37])[CH3:40]Participants
7
Conditions
- Temperature
- 0 °C
Procedure
To a stirring suspension of D,L-Phe(αMe)-OH (7.5 g, 42 mmol) in tetrahydrofuran (250 mL) was added N,O-bis(trimethylsilyl)acetamide (12.8 g, 62.8 mmol). Upon clarification the solution was cooled to 0° C. and N,N-diisopropylethylamine (5.4 g, 42 mmol) was added, followed by ethyl chloroformate (4.5 g, 42 mmol). After 2 h, water (100 mL) was added and then the organic solvent was removed in vacuo. The aqueous phase was diluted with 1N NaOH and washed twice with diethyl ether. The aqueous phase was then acidified to pH 2 with concentrated HCl and extracted three times with ethyl acetate. The combined ethyl acetate extracts were dried (Na2SO4), filtered and concentrated in vacuo to give 10.3 g (98% yield) of a white solid.
Workup
- customthe organic solvent was removed in vacuo
- additionThe aqueous phase was diluted with 1N NaOH
- washwashed twice with diethyl ether
- extractionextracted three times with ethyl acetate
- dry with materialThe combined ethyl acetate extracts were dried (Na2SO4)
- filtrationfiltered
- concentrationconcentrated in vacuo
Sources & evidence
- ORD record
- ord-7656687a574b4fa383524df790d8c9f3
- Source dataset
- uspto-grants-1995_07
- Patent number
- US05436229
Reaction notes
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