Benzeneacetic acid, 3,4-dimethoxy-, methyl ester → alpha-[5-[[(1,1-Dimethylethyl)dimethylsilyl]oxy]pentyl]-3,4-dimethoxybenzeneacetic acid methyl ester

HRID 863916Notes

Reaction equation

HRID 863916 reaction equation
[CH3:1][O:2][C:3](=[O:15])[CH2:4][C:5]1[CH:10]=[CH:9][C:8]([O:11][CH3:12])=[C:7]([O:13][CH3:14])[CH:6]=1.[Na].BrCCCCC[Si:23]([C:26]([CH3:29])([CH3:28])[CH3:27])([CH3:25])[CH3:24]>O1CCCC1.C(OCC)C.O>[CH3:1][O:2][C:3](=[O:15])[CH:4]([CH2:7][CH2:6][CH2:5][CH2:4][CH2:3][O:2][Si:23]([C:26]([CH3:27])([CH3:28])[CH3:29])([CH3:24])[CH3:25])[C:5]1[CH:10]=[CH:9][C:8]([O:11][CH3:12])=[C:7]([O:13][CH3:14])[CH:6]=1

Participants

7

Reactant 3

HCID 85213Benzeneacetic acid, 3,4-dimethoxy-, methyl esterHCID 5360545SodiumHCID 19042078(5-Bromopentyl)(1,1-dimethylethyl)dimethyl silane

Product 1

HCID 54212729alpha-[5-[[(1,1-Dimethylethyl)dimethylsilyl]oxy]pentyl]-3,4-dimethoxybenzeneacetic acid methyl esterYield 111.9%

Reagents, catalysts & solvents 3

HCID 962WaterSolventHCID 3283Diethyl EtherSolventHCID 8028TetrahydrofuranSolvent

Conditions

Temperature
-78 °C

Procedure

To a solution, -78° C. under argon, of 2.38 g of 3,4-dimethoxyphenyl acetic acid methyl ester in 30 ml of tetrahydrofuran is added 12.45 ml of 1.0M sodium hexamethylsidilazide. The solution is stirred at -78° C. for 5 minutes and then warmed to 0° C. for 1 hour. To this solution is added 3.5 g of (5-bromopentyl)(1,1-dimethylethyl)dimethyl silane. The reaction mixture is allowed to warm to room temperature and stirred for 12 hours. The mixture is diluted with diethyl ether and water, the layers are separated and the organic layer is washed with saturated sodium chloride, dried and concentrated in vacuo. The residue is purified by chromatography (silica gel: hexane/ethyl acetate,5/1) to give 2.6 g of the desired product as a clear oil. MS(Hi res): calcd 410.2488 found 410.2492

Workup

  1. temperaturewarmed to 0° C. for 1 hour
  2. temperatureto warm to room temperature
  3. stirringstirred for 12 hours
  4. customthe layers are separated
  5. washthe organic layer is washed with saturated sodium chloride
  6. customdried
  7. concentrationconcentrated in vacuo
  8. customThe residue is purified by chromatography (silica gel: hexane/ethyl acetate,5/1)

Sources & evidence

ORD record
ord-2b4e10041cf64a13803aa2c03f053663
Source dataset
uspto-grants-1996_10
Patent number
US05561141

Reaction notes

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