2-Methylbenzenesulfonic acid → 3,3-Diethyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine

HRID 1582407Notes

Reaction equation

HRID 1582407 reaction equation
[CH3:1][O:2][C:3]1[C:7]([O:8][CH3:9])=[CH:6][S:5][CH:4]=1.[CH2:10]([C:12]([CH2:17][CH3:18])(CO)CO)[CH3:11].C1(C)C(S(O)(=O)=O)=CC=CC=1>C1(C)C=CC=CC=1>[CH2:10]([C:12]1([CH2:17][CH3:18])[CH2:1][O:2][C:3]2=[CH:4][S:5][CH:6]=[C:7]2[O:8][CH2:9]1)[CH3:11]

Participants

5

Reactant 3

HCID 69252-Methylbenzenesulfonic acidHCID 8284PrenderolHCID 36135013,4-Dimethoxythiophene

Product 1

HCID 117360033,3-Diethyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepineYield 68%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Conditions

Temperature
25 °C

Procedure

3,4-Dimethoxythiophene (5.0 g, 34.7 mmol), 2,2-diethyl-1,3-propanediol (36.4 mmol), toluenesulfonic acid (0.2 g), and dry toluene (200 mL) were placed in a 500 mL round bottom flask equipped with a soxhlet extractor that contained a molecular sieve (4A)-filled extraction thimble. The solution was refluxed for 12 h under argon atmosphere, then cooled to 25° C. The solvent was removed under reduced pressure, the mixture diluted with 250 mL diethyl ether, extracted with 5% ammonium hydroxide (200 mL), and the extracted with water (2×200 mL). The organic layer was dried over anhydrous magnesium sulphate and the ether distilled off under reduced pressure, leaving an oil. This oil was further purified using column chromatography (silica and hexanes/ethyl acetate, 90/10) to yield 3,3-diethyl-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine as a colourless oil in 68% yield.

Workup

  1. customequipped with a soxhlet extractor that
  2. addition)-filled
  3. extractionextraction thimble
  4. temperatureThe solution was refluxed for 12 h under argon atmosphere
  5. customThe solvent was removed under reduced pressure
  6. additionthe mixture diluted with 250 mL diethyl ether
  7. extractionextracted with 5% ammonium hydroxide (200 mL)
  8. extractionthe extracted with water (2×200 mL)
  9. dry with materialThe organic layer was dried over anhydrous magnesium sulphate
  10. distillationthe ether distilled off under reduced pressure
  11. customleaving an oil
  12. customThis oil was further purified

Sources & evidence

ORD record
ord-1d715651fcc346b285d6f74d5ce2a12b
Source dataset
uspto-grants-2004_05
Patent number
US06734312B2

Reaction notes

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