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

HRID 274025

Reaction equation

COC1[CH:11]=[C:10]2[C:6](CNC2)=[CH:5][C:4]=1[OH:12].[CH3:13][O:14][C:15](=[O:27])[CH2:16][C:17]1[CH:22]=[CH:21][C:20]([O:23][CH3:24])=[C:19]([O:25][CH3:26])[CH:18]=1.[Na].BrCCCC[CH2:34][Si:35]([C:38]([CH3:41])([CH3:40])[CH3:39])(C)[CH3:36]>O1CCCC1.C(OCC)C.O>[CH3:13][O:14][C:15](=[O:27])[CH:16]([CH2:11][CH2:10][CH2:6][CH2:5][CH2:4][O:12][Si:35]([C:38]([CH3:41])([CH3:40])[CH3:39])([CH3:36])[CH3:34])[C:17]1[CH:22]=[CH:21][C:20]([O:23][CH3:24])=[C:19]([O:25][CH3:26])[CH:18]=1

Participants

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.

Workup

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

Sources & evidence

ORD record: ord-278b8b799112408cad48b628991a6464
Source dataset: uspto-grants-1995_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US05387685

Linked notes

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