p-Toluenesulfonic acid → Ethyl (([5,5-dimethyl-2-(4-methylphenyl)-1,3-dioxan-2-yl]methyl}thio)acetate

HRID 254092Notes

Reaction equation

HRID 254092 reaction equation
[CH3:1][C:2]1[CH:7]=[CH:6][C:5]([C:8](=[O:17])[CH2:9][S:10][CH2:11][C:12]([O:14][CH2:15][CH3:16])=[O:13])=[CH:4][CH:3]=1.[CH3:18][C:19]([CH3:24])([CH2:22]O)[CH2:20][OH:21].C1(C)C=CC(S(O)(=O)=O)=CC=1>C1C=CC=CC=1>[CH3:18][C:19]1([CH3:24])[CH2:20][O:21][C:8]([CH2:9][S:10][CH2:11][C:12]([O:14][CH2:15][CH3:16])=[O:13])([C:5]2[CH:6]=[CH:7][C:2]([CH3:1])=[CH:3][CH:4]=2)[O:17][CH2:22]1

Participants

5

Reactant 3

HCID 6101p-Toluenesulfonic acidHCID 31344Neopentyl glycolHCID 14923348Ethyl {[2-(4-methylphenyl)-2-oxoethyl]thio}acetate

Product 1

HCID 86619091Ethyl (([5,5-dimethyl-2-(4-methylphenyl)-1,3-dioxan-2-yl]methyl}thio)acetateYield 61%

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent

Procedure

Ethyl {[2-(4-methylphenyl)-2-oxoethyl]thio}acetate (12.2 g, 48.4 mmol) was dissolved in benzene (350 ml). 2,2-Dimethyl-1,3-propanediol (40.3 g, 0.387 mol) and p-toluene sulfonic acid (1 g) were added. The mixture was stirred at reflux in a Dean-Stark apparatus for two hours, cooled and concentrated under reduced pressure. CH2Cl2 was added and the organic phase was washed twice with brine and dried (MgSO4). Filtration and concentration under reduced pressure afforded a crude oil, which was purified by flash-chromatography (hexane:EtOAc 8:1) to afford 10.0 g (61%) of the title compound as a clear oil.

Workup

  1. temperatureat reflux in a Dean-Stark apparatus for two hours
  2. temperaturecooled
  3. concentrationconcentrated under reduced pressure
  4. additionCH2Cl2 was added
  5. washthe organic phase was washed twice with brine
  6. dry with materialdried (MgSO4)
  7. filtrationFiltration and concentration under reduced pressure
  8. customafforded a crude oil, which
  9. customwas purified by flash-chromatography (hexane:EtOAc 8:1)

Sources & evidence

ORD record
ord-d5a296d3ee814f9284ca22e38f2122d1
Source dataset
uspto-grants-2011_01
Patent number
US07871998B2

Reaction notes

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