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

HRID 1843276Notes

Reaction equation

HRID 1843276 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-carboxylate

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a solution of 131b (33.0 g, crude) in dichloromethane (400 mL) and triethylamine (60 g, 600 mmol) was added ethyl 2-mercaptoacetate (19.2 g, 160 mmol). See FIG. 15. 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 131c as a 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 to 131c as a yellow solid (18.0 g, 32%, over two steps)

Sources & evidence

ORD record
ord-6606398a5fcd487c8a7377fd2cfb7c37
Source dataset
uspto-grants-2015_02
Patent number
US08946213B2

Reaction notes

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