Water → HCID 10355055, compound

HRID 2108086Notes

Reaction equation

HRID 2108086 reaction equation
[CH3:1][O:2][C:3]1[CH:4]=[C:5]([SH:11])[CH:6]=[CH:7][C:8]=1[O:9][CH3:10].[OH-:12].[Na+].[OH2:14]>C(O)C>[CH3:1][O:2][C:3]1[CH:4]=[C:5]([S:11][CH2:4][CH2:3][CH2:8][C:7]([OH:14])=[O:12])[CH:6]=[CH:7][C:8]=1[O:9][CH3:10]

Participants

5

Reactant 3

HCID 962WaterHCID 14798Sodium HydroxideHCID 1365393,4-Dimethoxybenzene-1-thiol

Product 1

HCID 10355055HCID 10355055, compound

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent2×

Procedure

In ethanol (50 ml) is dissolved 3,4-dimethoxythiophenol (28 g), to the resulting mixture is added an ethanol solution (77 ml) of 2.5M sodium hydroxide, and the mixture is heated for 10 minutes under reflux. To the reaction mixture is then added τ-butyrolactone (18.5 g) and the mixture is heated for 3 hours under reflux. To the reaction mixture is added water (100 ml), then ethanol is distilled off under reduced pressure. The remaining aqueous solution is washed with ethyl acetate, and the aqueous layer is acidified with dilute hydrochloric acid. The mixture is extracted with ethyl acetate. The organic layer is washed with water and dried, followed by distilling off the solvent under reduced pressure. The residue is recrystallized from ether-hexane to afford 4-(3,4-dimethoxyphenylthio)butyric acid as colorless prisms (m.p. 78° C.) (20.5 g). Then, 4-(3,4dimethoxyphenylthio)butyric acid (14.5 g) is added to polyphosphoric acid (183 g), and the mixture is stirred at 100° C. for two hours. The reaction mixture is poured into ice-water (500 ml), followed by extraction with ethyl acetate. The organic layer is washed with water, dried, and concentrated under reduced pressure. The residue is purified by means of a silica gel column chromatography (eluent:hexane - ethyl acetate=5:1) to afford 7,8-dimethoxy-3,4-dihydro-1-benzothiepin-5(2H)-one (12.0 g). Recrystallization of the product from hexane - methylene chloride give colorless prisms, m.p. 128°-129° C.

Workup

  1. temperaturethe mixture is heated for 10 minutes
  2. temperatureunder reflux
  3. temperatureunder reflux
  4. distillationethanol is distilled off under reduced pressure
  5. washThe remaining aqueous solution is washed with ethyl acetate
  6. extractionThe mixture is extracted with ethyl acetate
  7. washThe organic layer is washed with water
  8. customdried
  9. distillationby distilling off the solvent under reduced pressure
  10. customThe residue is recrystallized from ether-hexane

Sources & evidence

ORD record
ord-aa62abaf96244518bef7424d49aa3b97
Source dataset
uspto-grants-1990_06
Patent number
US04937246

Reaction notes

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