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 2240804Notes

Reaction equation

HRID 2240804 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 evaporate. 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. customevaporate
  8. customThe crude product is purified by CC on silica gel eluting with heptane:EA 7:3

Sources & evidence

ORD record
ord-2a23bb0265b04a5bb33ca9791bdc4786
Source dataset
uspto-grants-2010_05
Patent number
US07723378B2

Reaction notes

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