3-Ethyl-5,5-dimethyl-4,5,6,7-tetrahydro-benzo[c]thiophene-1-carboxylic acid → 1-(3-Ethyl-5,5-dimethyl-4,5,6,7-tetrahydro-benzo[c]thiophen-1-yl)-ethanone

HRID 1013441Notes

Reaction equation

HRID 1013441 reaction equation
[CH2:1]([C:3]1[S:7][C:6]([C:8]([OH:10])=O)=[C:5]2[CH2:11][CH2:12][C:13]([CH3:16])([CH3:15])[CH2:14][C:4]=12)[CH3:2].[CH3:17][Li]>C(OCC)C>[CH2:1]([C:3]1[S:7][C:6]([C:8](=[O:10])[CH3:17])=[C:5]2[CH2:11][CH2:12][C:13]([CH3:16])([CH3:15])[CH2:14][C:4]=12)[CH3:2]

Participants

4

Reactant 2

HCID 574374183-Ethyl-5,5-dimethyl-4,5,6,7-tetrahydro-benzo[c]thiophene-1-carboxylic acidHCID 178418348HCID 178418348, compound3×

Product 1

HCID 574374251-(3-Ethyl-5,5-dimethyl-4,5,6,7-tetrahydro-benzo[c]thiophen-1-yl)-ethanone

Reagents, catalysts & solvents 1

HCID 3283Diethyl EtherSolvent

Procedure

To a solution of 3-ethyl-5,5-dimethyl-4,5,6,7-tetrahydro-benzo[c]thiophene-1-carboxylic acid (2.10 g, 8.81 mmol) in diethyl ether (100 mL), a solution of methyllithium (11 mL, 1.6 M solution in diethyl ether) is added at rt. The pale yellow solution is stirred at rt for 15 min before another portion of methyllithium (2 mL) is added. Stirring is continued for 15 min, a further portion of methyllithium (1 mL) is added, and the mixture is again stirred for 15 min at rt. The reaction is quenched with water. The organic layer is separated, washed once more with water, dried over MgSO4 and evaporated. The crude product is purified by CC on silica gel eluting with heptane:EA 7:3 to give 1-(3-ethyl-5,5-dimethyl-4,5,6,7-tetrahydro-benzo[c]thiophen-1-yl)-ethanone (1.65 g) as a pale yellow solid; LC-MS: tR=1.00 min; [M+1]=237.15; 1H NMR (CDCl3): δ 3.03 (t, J=7.0 Hz, 2H), 2.73 (q, J=7.6 Hz, 2H), 2.47 (s, 3H), 2.31 (s, 2H), 1.55 (t, J=7.0 Hz, 2H), 1.28 (t, J=7.6 Hz, 3H), 0.97 (s, 6H).

Workup

  1. additionis added
  2. stirringthe mixture is again stirred for 15 min at rt
  3. customThe reaction is quenched with water
  4. customThe organic layer is separated
  5. washwashed once more with water
  6. dry with materialdried over MgSO4
  7. customevaporated
  8. customThe crude product is purified by CC on silica gel eluting with heptane:EA 7:3

Sources & evidence

ORD record
ord-5610634bf46c4e48980b1613aef5f9db
Source dataset
uspto-grants-2011_07
Patent number
US07981924B2

Reaction notes

Loading…