Ethylene Glycol → 2-(4-Bromothiophen-2-yl)-1,3-dioxolane

HRID 900989Notes

Reaction equation

HRID 900989 reaction equation
[Br:1][C:2]1[CH:3]=[C:4]([CH:7]=[O:8])[S:5][CH:6]=1.[CH2:9](O)[CH2:10][OH:11]>C1(C)C=CC=CC=1.C1(C)C=CC(S(O)(=O)=O)=CC=1>[Br:1][C:2]1[CH:3]=[C:4]([CH:7]2[O:11][CH2:10][CH2:9][O:8]2)[S:5][CH:6]=1

Participants

5

Reactant 2

HCID 174Ethylene GlycolHCID 877924-Bromothiophene-2-carbaldehyde

Product 1

HCID 38572552-(4-Bromothiophen-2-yl)-1,3-dioxolaneYield 98%

Reagents, catalysts & solvents 2

HCID 6101p-Toluenesulfonic acidCatalystHCID 1140TolueneSolvent

Procedure

A mixture of 4-bromo-thiophene-2-carbaldehyde (175 g, 916 mmol), ethylene glycol (71.1 g, 1.15 mol) and p-toluenesulfonic acid (0.19 g, 1.0 mmol) in toluene (250 mL) is heated to reflux for 7 h using a Dean-Stark apparatus. After cooling, the solution is washed with aq NaHCO3, dried over Na2SO4, filtered and concentrated in vacuo. The residue is distilled to give 2-(4-bromo-thiophen-2-yl)-[1,3]dioxolane (210.6 g, 98%) as a colorless liquid: bp 133-143/11-14 mBar; 1H NMR (CDCl3, 300 MHz) δ 7.21 (s, 1 H), 7.04 (s, 1 H), 6.04 (s, 1 H), 3.95-4.18 (m, 4 H).

Workup

  1. temperatureis heated
  2. temperatureto reflux for 7 h
  3. temperatureAfter cooling
  4. washthe solution is washed with aq NaHCO3
  5. dry with materialdried over Na2SO4
  6. filtrationfiltered
  7. concentrationconcentrated in vacuo
  8. distillationThe residue is distilled

Sources & evidence

ORD record
ord-3ef4551a5af34ca18169c18ad9c958ae
Source dataset
uspto-grants-2008_04
Patent number
US07361671B2

Reaction notes

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