Benzyl chloroformate → 1-Benzyl 2,3-di-tert-butyl pyrazolidine-1,2,3-tricarboxylate

HRID 1396894Notes

Reaction equation

HRID 1396894 reaction equation
C([O-])([O-])=O.[K+].[K+].Cl[C:8]([O:10][CH2:11][C:12]1[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=1)=[O:9].[N:18]1([C:30]([O:32][C:33]([CH3:36])([CH3:35])[CH3:34])=[O:31])[CH:22]([C:23]([O:25][C:26]([CH3:29])([CH3:28])[CH3:27])=[O:24])[CH2:21][CH2:20][NH:19]1>C(#N)C>[N:19]1([C:8]([O:10][CH2:11][C:12]2[CH:17]=[CH:16][CH:15]=[CH:14][CH:13]=2)=[O:9])[CH2:20][CH2:21][CH:22]([C:23]([O:25][C:26]([CH3:28])([CH3:29])[CH3:27])=[O:24])[N:18]1[C:30]([O:32][C:33]([CH3:36])([CH3:35])[CH3:34])=[O:31]

Participants

5

Reactant 3

HCID 10387Benzyl chloroformateHCID 11430Potassium CarbonateHCID 68287714Di-tert-butyl pyrazolidine-1,5-dicarboxylate

Product 1

HCID 867063391-Benzyl 2,3-di-tert-butyl pyrazolidine-1,2,3-tricarboxylateYield 74.4%

Reagents, catalysts & solvents 1

HCID 6342AcetonitrileSolvent

Procedure

Sat. aq. K2CO3 (210 mL) was added into a solution of benzyl chloroformate (12.0 ml, 84 mmol) and crude di-tert-butyl pyrazolidine-1,5-dicarboxylate (12.74 g, assumed 46.8 mmol) in acetonitrile (137 ml) at 0° C. The reaction was allowed to warm to room temperature and was stirred for 4.5 hrs. The aqueous phase was extracted with EtOAc (3×100 mL), and the organic layers were dried over Na2SO4. The solvents were removed in vacuo, and the crude product was purified by silica gel chromatography (CombiFlash, Column: 220 g; 0-35% ethyl acetate in hexane; 60 min) to provide the desired product 1-benzyl 2,3-di-tert-butyl pyrazolidine-1,2,3-tricarboxylate (14.15 g, 74% yield) as a white solid.

Workup

  1. extractionThe aqueous phase was extracted with EtOAc (3×100 mL)
  2. dry with materialthe organic layers were dried over Na2SO4
  3. customThe solvents were removed in vacuo
  4. customthe crude product was purified by silica gel chromatography (CombiFlash, Column: 220 g; 0-35% ethyl acetate in hexane; 60 min)

Sources & evidence

ORD record
ord-6daca42062404ff39d7acda688055210
Source dataset
uspto-grants-2014_12
Patent number
US08901119B2

Reaction notes

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