Ethylene Glycol → 6-Bromo-1,4-dioxaspiro[4.6]undecane

HRID 582832

Reaction equation

HRID 582832 reaction equation
[Br:1]Br.[C:3]1(=[O:10])[CH2:9][CH2:8][CH2:7][CH2:6][CH2:5][CH2:4]1.[CH2:11]([OH:14])[CH2:12]O.C(=O)(O)[O-].[Na+]>O1CCCC1>[CH2:11]1[O:14][C:3]2([CH2:9][CH2:8][CH2:7][CH2:6][CH2:5][CH:4]2[Br:1])[O:10][CH2:12]1

Participants

6

Reactant 4

HCID 174Ethylene GlycolHCID 10400CycloheptanoneHCID 24408BromineHCID 516892Sodium Bicarbonate

Product 1

HCID 2882266-Bromo-1,4-dioxaspiro[4.6]undecane

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

Bromine (44.8 g, 0.28 mol) was added dropwise to a stirred solution of cycloheptanone (28.5 g, 0.25 mol) in a 1:1 solution (300 mL) of ethylene glycol and tetrahydrofuran at room temperature. The mixture was stirred for 5 hours, then poured into aqueous sodium bicarbonate and extracted 3× with diethyl ether. The combined organic layers were washed with brine, dried over sodium sulfate, filtered, and concentrated in vacuo to give 2-bromocycloheptanone ethylene ketal(60 g). A mixture of this crude bromo ketal and a methanolic solution of sodium methoxide (250 mL, 25 wt. % solution) was heated at reflux overnight. The mixture was cooled to ambient temperature, poured into water, and extracted with hexanes. The organic layer was washed with brine, dried over sodium sulfate, filtered, and concentrated in vacuo to afford 2-cycloheptenone ethylene ketal (39 g).

Workup

  1. extractionextracted 3× with diethyl ether
  2. washThe combined organic layers were washed with brine
  3. dry with materialdried over sodium sulfate
  4. filtrationfiltered
  5. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-e2233c6b7c3b424b9d18d4c9cf190052
Source dataset
uspto-grants-1999_07
Patent number
US05925770

Linked notes

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