p-Toluenesulfonic acid → HCID 18948918, compound

HRID 1975080Notes

Reaction equation

HRID 1975080 reaction equation
[Br:1][C:2]1[CH:3]=[C:4]2[C:10]([CH3:12])([CH3:11])[S:9][CH:8](O)[CH:5]2[O:6][CH:7]=1.C1(C)C=CC(S(O)(=O)=O)=CC=1>C1C=CC=CC=1>[Br:1][C:2]1[CH:3]=[C:4]2[C:10]([CH3:12])([CH3:11])[S:9][CH:8]=[C:5]2[O:6][CH:7]=1

Participants

4

Reactant 2

HCID 6101p-Toluenesulfonic acidHCID 67806074HCID 67806074, compound

Product 1

HCID 18948918HCID 18948918, compound

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent

Procedure

A solution of 3-bromo-5,6-dihydro-7-hydroxy-5,5-dimethyl -7H-thieno[3,4-b]pyran (12.06 g, 45.8 mmol) and p-toluenesulfonic acid (0.26 g, 1.37 mmol) in benzene (300 mi) was heated to reflux for 3 h in an apparatus fitted with a Dean-Stark trap to remove water. The resultant solution was cooled to rt and filtered through a pad of silica gel and the silica gel was washed with dichloromethane; the organic solutions were combined. The solvent was evaporated in vacuo to give the product as a brown oil, 10.23 g (91%); 1H NMR (CDCl3): δ 1.38 (s,6H), 5.65 (d, J=14 Hz, 1H), 6.37 (d, J=14 Hz, 1H) and 6.87 (s, 1H).

Workup

  1. temperatureto reflux for 3 h in an apparatus
  2. customfitted with a Dean-Stark trap
  3. customto remove water
  4. filtrationfiltered through a pad of silica gel
  5. washthe silica gel was washed with dichloromethane
  6. customThe solvent was evaporated in vacuo

Sources & evidence

ORD record
ord-5ae7cbfd09ca45c4bd31a75dc01cd9b1
Source dataset
uspto-grants-1994_02
Patent number
US05284857

Reaction notes

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