Triethylamine → Ethyl 5,5-Dimethyl-5,6-dihydro-4H-cyclopenta[b]thiophene-2-carboxylate

HRID 1411984Notes

Reaction equation

HRID 1411984 reaction equation
Cl[C:2]1[CH2:6][C:5]([CH3:8])([CH3:7])[CH2:4][C:3]=1[CH:9]=O.C(N(CC)CC)C.[SH:18][CH2:19][C:20]([O:22][CH2:23][CH3:24])=[O:21]>ClCCl>[CH3:8][C:5]1([CH3:7])[CH2:6][C:2]2[S:18][C:19]([C:20]([O:22][CH2:23][CH3:24])=[O:21])=[CH:9][C:3]=2[CH2:4]1

Participants

5

Reactant 3

HCID 8471Triethylamine2×HCID 12185Ethyl ThioglycolateHCID 866612412-Chloro-4,4-dimethylcyclopent-1-enecarbaldehyde

Product 1

HCID 58043720Ethyl 5,5-Dimethyl-5,6-dihydro-4H-cyclopenta[b]thiophene-2-carboxylateYield 50.2%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a solution of 282b (33.0 g, crude) in dichloromethane (400 mL) and triethylamine (60 g, 600 mmol) was added ethyl 2-mercaptoacetate (19.2 g, 160 mmol). The reaction mixture was heated at reflux for 6 h. It was then concentrated under reduced pressure. The residue was dissolved in ethanol (400 mL) and triethylamine (60 g, 600 mmol). The mixture was heated at reflux for 12 h. It was concentrated again under reduced pressure and the residue was purified by silica-gel column chromatography eluting with 40:1 petroleum ether/ethyl acetate to afford 282c as yellow solid (18.0 g, 32%, over two steps). MS-ESI: [M+H]+ 225.3. 1H NMR (500 MHz, DMSO-d6) δ 7.49 (s, 1H), 4.32 (q, J=7.0 Hz, 2H), 2.72 (s, 2H), 2.56 (s, 2H), 1.35 (t, J=7.0 Hz, 3H), 1.22 (s, 6H).

Workup

  1. temperatureThe reaction mixture was heated
  2. temperatureat reflux for 6 h
  3. concentrationIt was then concentrated under reduced pressure
  4. dissolutionThe residue was dissolved in ethanol (400 mL)
  5. temperatureThe mixture was heated
  6. temperatureat reflux for 12 h
  7. concentrationIt was concentrated again under reduced pressure
  8. customthe residue was purified by silica-gel column chromatography
  9. washeluting with 40:1 petroleum ether/ethyl acetate

Sources & evidence

ORD record
ord-75b27bd2dfc24dbc862a55fde0c7889b
Source dataset
uspto-grants-2014_12
Patent number
US08921353B2

Reaction notes

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