Sodium cyanoborohydride → Di-tert-butyl pyrazolidine-1,5-dicarboxylate

HRID 1396852Notes

Reaction equation

[N:1]1([C:13]([O:15][C:16]([CH3:19])([CH3:18])[CH3:17])=[O:14])[CH:5]([C:6]([O:8][C:9]([CH3:12])([CH3:11])[CH3:10])=[O:7])[CH2:4][CH:3]=[N:2]1.C([BH3-])#N.[Na+]>C(O)(=O)C.CCOC(C)=O.C([O-])([O-])=O.[Na+].[Na+]>[N:1]1([C:13]([O:15][C:16]([CH3:19])([CH3:18])[CH3:17])=[O:14])[CH:5]([C:6]([O:8][C:9]([CH3:11])([CH3:12])[CH3:10])=[O:7])[CH2:4][CH2:3][NH:2]1

Participants

Conditions

Temperature: 25 °C

Procedure

Di-tert-butyl 4,5-dihydropyrazole-1,5-dicarboxylate (12.65 g, 46.8 mmol) was dissolved in acetic acid (69.2 ml), and the solution was cooled in a water bath. Sodium cyanoborohydride (5.88 g, 94 mmol) was added portionwise under N2. The reaction was stirred at 25° C. for 5 hrs. The solvent was then removed under reduced pressure to give a residue. The residue was diluted with EtOAc (150 mL), and Na2CO3 (sat.) (100 mL) was cautiously added to the solution. The layers were separated and the aq. solution was extracted with EtOAc (2×30 mL), and the organics were dried over Na2SO4. The solvent was removed under reduced pressure to give the crude product di-tert-butyl pyrazolidine-1,5-dicarboxylate (12.74 g) as light yellow oil, which was used directly in the next step.

Workup

temperaturethe solution was cooled in a water bath
customThe solvent was then removed under reduced pressure
customto give a residue
additionwas cautiously added to the solution
customThe layers were separated
extractionthe aq. solution was extracted with EtOAc (2×30 mL)
dry with materialthe organics were dried over Na2SO4
customThe solvent was removed under reduced pressure

Sources & evidence

ORD record: ord-3c03b441b5244ec1ad71c572074dcbca
Source dataset: uspto-grants-2014_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08901119B2

Reaction notes

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