Phosgene → HCID 69131963, compound
Reaction equation
[C:1](Cl)(Cl)=[O:2].[CH2:5]([O:12][C:13]([N:15]1[CH2:20][CH2:19][NH:18][CH2:17][CH2:16]1)=[O:14])[C:6]1[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=1.C(N(C(C)C)C1C=CC=CC=1)(C)C.[C:34]([O:38][C:39]([NH:41][NH2:42])=[O:40])([CH3:37])([CH3:36])[CH3:35].C(N(C(C)C)CC)(C)C>C(Cl)Cl>[CH2:5]([O:12][C:13]([N:15]1[CH2:20][CH2:19][N:18]([C:1]([N:41]([C:39]([O:38][C:34]([CH3:37])([CH3:36])[CH3:35])=[O:40])[NH2:42])=[O:2])[CH2:17][CH2:16]1)=[O:14])[C:6]1[CH:11]=[CH:10][CH:9]=[CH:8][CH:7]=1Participants
Procedure
To a phosgene solution (20% solution in toluene) at 0° C. was added piperazine-1-carboxylic acid benzyl ester (0.385 mL, 1.996 mmol) and diisopropylphenyl amine (0.383 mL, 4.397 mmol) in 5 mL of CH2Cl2 dropwise. The resulting pale yellow mixture was stirred 2 h warming to room temperature under Ar. The phosgene solution was removed by vacuum distillation. 20 mL of anhydrous CH2Cl2 was added. The reaction vessel was cooled to 0° C. and hydrazinecarboxylic acid tert-butyl ester and diisopropylethyl amine (0.383 mL, 4.397 mmol) was added in one portion. The reaction was warmed to room temperature and stirred for 1 h. The reaction was quenched with 10 mL of saturated NaHCO3, diluted with 30 mL of EtOAc, then washed with 2×30 mL of saturated NH4Cl solution and 30 mL of brine. The organic phase was dried over MgSO4, filtered and concentrated to provide 720 mg of 4-(N-tert-butoxycarbonyl-hydrazinocarbonyl)-piperazine-1-carboxylic acid benzyl ester as a white solid.
Workup
- customThe phosgene solution was removed by vacuum distillation
- addition20 mL of anhydrous CH2Cl2 was added
- temperatureThe reaction vessel was cooled to 0° C.
- temperatureThe reaction was warmed to room temperature
- stirringstirred for 1 h
- customThe reaction was quenched with 10 mL of saturated NaHCO3
- additiondiluted with 30 mL of EtOAc
- washwashed with 2×30 mL of saturated NH4Cl solution and 30 mL of brine
- dry with materialThe organic phase was dried over MgSO4
- filtrationfiltered
- concentrationconcentrated
Sources & evidence
- ORD record
- ord-dd8bf535f7bd4c028810579529d7488e
- Source dataset
- uspto-grants-2005_11
- Patent number
- US06964956B2
Reaction notes
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