Acetyl chloride → 5-Acetyl-2,3-dimethylthiophene

HRID 51228Notes

Reaction equation

HRID 51228 reaction equation
[CH3:1][C:2]1[S:3][CH:4]=[CH:5][C:6]=1[CH3:7].[C:8](Cl)(=[O:10])[CH3:9].[Sn](Cl)(Cl)(Cl)Cl>C1C=CC=CC=1>[CH3:7][C:6]1[CH:5]=[C:4]([C:8]([CH3:9])=[O:10])[S:3][C:2]=1[CH3:1]

Participants

5

Reactant 3

HCID 6367Acetyl chlorideHCID 24287Tin tetrachlorideHCID 342952,3-Dimethylthiophene

Product 1

HCID 2986125-Acetyl-2,3-dimethylthiopheneYield 99.9%

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent2×

Conditions

Temperature
-5 °C

Procedure

A solution of 5 (15.16 g, 135 mmole) and acetyl chloride (9.6 mL, 135 mmole) in 60 mL benzene dried over Na was cooled to −5° C. and vigorously stirred during the addition of a solution of tin (IV) chloride in 50 mL benzene over a period of 1 hour. The reaction mixture was removed from the cold bath and stirred for an additional hour at room temperature. The slow addition of 4 mL concentrated HCl in 28 mL water quenched the reaction. The organic layer was separated, washed with 2×10 mL water, dried over Na2SO4 and evaporated to give 20.8 g of crude product. Chromatography on a column of silica eluted with pet. ethenethyl acetate (10:1) and evaporation of relevant fractions gave a viscous yellow oil, 16.42 g, 79%. 1H NMR (CDCl3) δ: 2.08, s, 3H, COCH3; 2.31, s, 3H, CH3; 2.41, s, 3H, CH3; 7.33, s, 1H, H-3. 13C NMR (CDCl3) δ: 13.3, 13.7, 26.1, 134.7 135.3, 139.1, 143.4, 190.0.

Workup

  1. customThe reaction mixture was removed from the cold bath
  2. additionThe slow addition of 4 mL concentrated HCl in 28 mL water
  3. customquenched
  4. customthe reaction
  5. customThe organic layer was separated
  6. washwashed with 2×10 mL water
  7. dry with materialdried over Na2SO4
  8. customevaporated

Sources & evidence

ORD record
ord-844e1846586f4658a71d936b64c1be3c
Source dataset
uspto-grants-2004_03
Patent number
US06713638B2

Reaction notes

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