Description
Hydroxy-PEG1-t-butyl ester is a PEG linker containing a hydroxyl group with a t-butyl ester. The hydrophilic PEG spacer increases solubility in aqueous media. The hydroxyl group enables further derivatization or replacement with other reactive functional groups. The t-butyl protected carboxyl group can be deprotected under acidic conditions.
Synthesis
To a solution of anhydrous ethylene glycol (10 g, 161.1 mmol) in anhydrous THF (40 mL) was added sodium metal (62.0 mg, 2.70 mmol) and stirred at room temperature for 2 hours.Add tert-butyl acrylate (6.90, 53.7 mmol) and stir overnight.After quenching with water, the solvent was THF dried under reduced pressure, and extracted with ethyl acetate and water.The organic layer was separated, washed with brine, and dried over Na 2 SO 4.After filtration and evaporation, the residue was purified by silica gel column chromatography (petroleum ether/ethyl acetate = 2:1) to obtain a colorless oil 44 (5.0 g, 26.3 mmol, 49% yield)
References
[1] Patent: WO2012/166560, 2012, A1. Location in patent: Page/Page column 171-172
[2] Patent: WO2013/192360, 2013, A1. Location in patent: Paragraph 00490
[3] Patent: WO2013/185117, 2013, A1. Location in patent: Paragraph 00476
[4] Patent: EP2409977, 2012, A1. Location in patent: Page/Page column 66
[5] Synthetic Communications, 2004, vol. 34, # 13, p. 2425 - 2432
