Isopropyl chloroformate → tert-Butyl 4-hydroxy-2-oxo-2,5-dihydro-1H-pyrrole-1-carboxylate
Reaction equation
[NH:1]([C:6]([O:8][C:9]([CH3:12])([CH3:11])[CH3:10])=[O:7])[CH2:2][C:3]([OH:5])=O.[CH3:13][C:14]1(C)OC(=O)CC(=O)[O:15]1.ClC(OC(C)C)=O>C(Cl)Cl.CN(C1C=CN=CC=1)C.C1(C)C=CC=CC=1>[OH:5][C:3]1[CH2:2][N:1]([C:6]([O:8][C:9]([CH3:12])([CH3:11])[CH3:10])=[O:7])[C:14](=[O:15])[CH:13]=1Participants
7
Reactant 3
Product 1
Reagents, catalysts & solvents 3
Conditions
- Temperature
- 0 °C
Procedure
To Boc-Gly-OH (1 g, 5.71 mmol) in DCM (12 mL) under N2 atmosphere at 0° C. was added DMAP (1.743 g, 14.27 mmol) and Meldrum's acid (0.987 g, 6.85 mmol). A solution of isopropyl chloroformate (8.56 mL, 8.56 mmol) in toluene was added dropwise. The reaction mixture was stirred at 0° C. for 3 h. The reaction mixture was washed with 15% KHSO4 twice, dried over sodium sulfate, filtered and evaporated. The crude product was taken in 50 mL of EtOAc and refluxed for 1 h. After volatile materials were evaporated, the crude product was triturated with EtOAC and the resulting solid was filtered and dried to provide a yellow solid (75%). LCMS (m/z): 200.1 (MH+), 0.504 min.
Workup
- washThe reaction mixture was washed with 15% KHSO4 twice
- dry with materialdried over sodium sulfate
- filtrationfiltered
- customevaporated
- temperaturerefluxed for 1 h
- customAfter volatile materials were evaporated
- customthe crude product was triturated with EtOAC
- filtrationthe resulting solid was filtered
- customdried
Sources & evidence
- ORD record
- ord-6b8739ad7f824f7b877047bc2db466d3
- Source dataset
- uspto-grants-2016_01
- Patent number
- US09242996B2
Reaction notes
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