p-Toluenesulfonic acid → 2,3-Dimethyl-2,3-dihydrothieno[3,4-b][1,4]dioxine

HRID 1582406Notes

Reaction equation

HRID 1582406 reaction equation
CO[C:3]1[C:7](OC)=[CH:6][S:5][CH:4]=1.[CH3:10][C@@H:11]([OH:15])[C@@H:12]([OH:14])[CH3:13].C1(C)C=CC(S(O)(=O)=O)=CC=1.C(Cl)Cl>C1(C)C=CC=CC=1>[CH3:10][CH:11]1[O:15][C:3]2=[CH:4][S:5][CH:6]=[C:7]2[O:14][CH:12]1[CH3:13]

Participants

6

Reactant 4

HCID 6101p-Toluenesulfonic acidHCID 6344DichloromethaneHCID 220010Meso-2,3-ButanediolHCID 36135013,4-Dimethoxythiophene

Product 1

HCID 235132022,3-Dimethyl-2,3-dihydrothieno[3,4-b][1,4]dioxineYield 21.5%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

A solution of 3,4-dimethoxythiophene (7.2 g, 50 mmol), meso-2,3-butanediol (5.4 g, 60 mmol), and p-toluenesulphonic acid (0.2 g) in toluene (100 ml) was heated at 100° C. under a continuous argon flow for 24 h. The reaction mixture was then poured into methylene chloride (200 mL) and the organic phase washed with a 1M aqueous solution of sodium hydrogen carbonate and brine, dried with anhydrous magnesium sulphate and concentrated. This resulted in a mixture of cis and trans product that could be separated by column chromatography, yielding pure cis (2.8 g, 16%) and trans (1.83 g, 11%) 2,3-dimethyl-2,3-dihydro-thieno[3,4-b][1,4]dioxine.

Workup

  1. washthe organic phase washed with a 1M aqueous solution of sodium hydrogen carbonate and brine
  2. dry with materialdried with anhydrous magnesium sulphate
  3. concentrationconcentrated
  4. customThis resulted in a mixture of cis and trans product that
  5. customcould be separated by column chromatography

Sources & evidence

ORD record
ord-6f548718716e494ea77455f34b019e7c
Source dataset
uspto-grants-2004_05
Patent number
US06734312B2

Reaction notes

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