1,8-Diazabicyclo(5.4.0)undec-7-ene → 1-tert-Butyl 2-methyl (2S)-2,5-dihydro-1H-pyrrole-1,2-dicarboxylate

HRID 1662609Notes

Reaction equation

I[C@@H:2]1[CH2:6][N:5]([C:7]([O:9][C:10]([CH3:13])([CH3:12])[CH3:11])=[O:8])[C@H:4]([C:14]([O:16][CH3:17])=[O:15])[CH2:3]1.N12CCCN=C1CCCCC2>C1(C)C=CC=CC=1>[N:5]1([C:7]([O:9][C:10]([CH3:13])([CH3:12])[CH3:11])=[O:8])[CH:6]=[CH:2][CH2:3][C@H:4]1[C:14]([O:16][CH3:17])=[O:15].[N:5]1([C:7]([O:9][C:10]([CH3:13])([CH3:12])[CH3:11])=[O:8])[CH2:6][CH:2]=[CH:3][C@H:4]1[C:14]([O:16][CH3:17])=[O:15]

Participants

Conditions

Temperature: 85 °C

Procedure

To a solution of 27.3 g of the compound obtained in Step 19-1 in toluene (500 ml) was added 1,8-diaza bicyclo[5,4,0]undec-7-ene (DBU) (12.7 ml) and the reaction mixture was stirred for 10 hours at an external temperature of 85° C. After being to cool, the precipitation was separated by filtration and the solvent was evaporated under reduced pressure. The obtained residue was separated and purified by column chromatography (silicagel 60; mobile phase: EtOAc/n-hexane=1/10 to 1/5; v/v) to obtain 4.15 g of 1-tert-butyl 2-methyl (2S)-2,3-dihydro-1H-pyrrole-1,2-dicarboxylate (colorless oil) and 12.5 g of 1-tert-butyl 2-methyl (2S)-2,5-dihydro-1H-pyrrole-1,2-dicarboxylate (colorless oil).

Workup

temperatureto cool
customthe precipitation
customwas separated by filtration
customthe solvent was evaporated under reduced pressure
customThe obtained residue was separated
custompurified by column chromatography (silicagel 60; mobile phase: EtOAc/n-hexane=1/10 to 1/5; v/v)

Sources & evidence

ORD record: ord-0cae5ed4e59f4c16b45aa3f60d3e8ad5
Source dataset: uspto-grants-2011_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08030499B2

Reaction notes

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