Ethyl 1,4,5,6-tetrahydrocyclopenta[b]pyrrole-2-carboxylate → Ethyl 6-oxo-1,4,5,6-tetrahydrocyclopenta[b]pyrrole-2-carboxylate

HRID 601894Notes

Reaction equation

HRID 601894 reaction equation
[NH:1]1[C:5]([C:6]([O:8][CH2:9][CH3:10])=[O:7])=[CH:4][C:3]2[CH2:11][CH2:12][CH2:13][C:2]1=2.C1C[O:17]CC1.O>C1COCC1>[O:17]=[C:13]1[C:2]2[NH:1][C:5]([C:6]([O:8][CH2:9][CH3:10])=[O:7])=[CH:4][C:3]=2[CH2:11][CH2:12]1

Participants

4

Reactant 2

HCID 15319183Ethyl 1,4,5,6-tetrahydrocyclopenta[b]pyrrole-2-carboxylateHCID 21881883Oxolane--water (1/1)

Product 1

HCID 57659859Ethyl 6-oxo-1,4,5,6-tetrahydrocyclopenta[b]pyrrole-2-carboxylate

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

A solution of the ethyl 1,4,5,6-tetrahydrocyclopenta[b]pyrrole-2-carboxylate (1.0 g, 5.58 mmol) in THF/Water (10:1, 11 mL) at 0° C. was deoxygenated by passing a stream of dry nitrogen gas for 10 min. A solution of 2,3-dichloro-5,6-dicyano-1,4-benzochinone (DDQ) in THF (4 mL) was added dropwise over 5 min. After stirring for 1.5 h, the cooling bath was removed and stirring was continued at rt. Silica gel was added, the solvent stripped off and the silica gel-imbedded material was purified by flash chromatography (0-60% EtOAc/Heptane) to afford ethyl 6-oxo-1,4,5,6-tetrahydrocyclopenta[b]pyrrole-2-carboxylate as a taupe solid (270 mg, 25%). 1H NMR (400 MHz, CHLOROFORM-d) δ ppm 1.39 (t, J=7.13 Hz, 3H), 2.87-2.95 (m, 4H), 4.39 (q, J=7.13 Hz, 2H), 6.78 (d, J=1.66 Hz, 1H), 9.86 (s, 1H); LCMS-MS (ESI+) 193.9 (M+H).

Workup

  1. customfor 10 min
  2. customthe cooling bath was removed
  3. stirringstirring
  4. customwas continued at rt
  5. additionSilica gel was added
  6. customthe silica gel-imbedded material was purified by flash chromatography (0-60% EtOAc/Heptane)

Sources & evidence

ORD record
ord-a98c0d4832f94d7ea0dd1aed6d458a43
Source dataset
uspto-grants-2011_03
Patent number
US07902252B2

Reaction notes

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