Ethylene Glycol → 2-(3-Bromothiophen-2-yl)-1,3-dioxolane

HRID 2352276Notes

Reaction equation

HRID 2352276 reaction equation
[Br:1][C:2]1[CH:6]=[CH:5][S:4][C:3]=1[CH:7]=[O:8].[CH2:9](O)[CH2:10][OH:11]>S(C1C=CC(C)=CC=1)([O-])(=O)=O.[NH+]1C=CC=CC=1.C1(C)C=CC=CC=1>[Br:1][C:2]1[CH:6]=[CH:5][S:4][C:3]=1[CH:7]1[O:11][CH2:10][CH2:9][O:8]1

Participants

5

Reactant 2

HCID 174Ethylene GlycolHCID 27970793-Bromothiophene-2-carboxaldehyde

Product 1

HCID 122202112-(3-Bromothiophen-2-yl)-1,3-dioxolaneYield 76.5%

Reagents, catalysts & solvents 2

HCID 466102Benzenesulfonic acid, 4-methyl-, compd. with pyridine (1:1)CatalystHCID 1140TolueneSolvent

Procedure

Pyridinium tosylate (1 g., 4 mmoles) was added to a mixture of 3-bromothiophene-2-carboxaldehyde (2) (18.7 g., 97.9 mmole), ethylene glycol (22 mL., 24.8 g., 400 mmole) and dry toluene (100 mL). The mixture was refluxed and the water removed by a Dean-Stark trap. After 1 hour, TLC (10% EtOAC/hexane) showed the reaction was complete. The mixture was cooled to room temperature and partitioned between ether (100 mL) and water (100 mL) components. The organic layer was separated and extracted with water (3×50 mL) and then with a saturated solution of sodium bicarbonate (25 mL). The resulting extract was dried (MgSO4), filtered and evaporated in vacuo to leave 21.5 g, of crude product. This product was distilled to give 17.6 g of 3 -Bromo-2-(2-dioxolanyl)thiophene (3), bp: 86°-87° C./0.5 mm.

Workup

  1. temperatureThe mixture was refluxed
  2. customthe water removed by a Dean-Stark trap
  3. custompartitioned between ether (100 mL) and water (100 mL) components
  4. customThe organic layer was separated
  5. extractionextracted with water (3×50 mL)
  6. extractionThe resulting extract
  7. dry with materialwas dried (MgSO4)
  8. filtrationfiltered
  9. customevaporated in vacuo
  10. customto leave 21.5 g
  11. distillationThis product was distilled

Sources & evidence

ORD record
ord-2a019121303a4149b40527c73144157f
Source dataset
uspto-grants-1989_10
Patent number
US04876271

Reaction notes

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