tert-butyl bis(2-hydroxyethyl)carbamate is a branched PEG with a tert-butyl protecting group and two hydroxyl end groups. The t-butyl group can be deprotected under acidic conditions. The hydroxyl group can react to further derivatize the compound. The hydrophilic PEG linker increases the water solubility of the compound in aqueous media.
Under nitrogen protection, 2,2'-Azabisethanol (4.21 g, 40 mmol) was dissolved in acetonitrile (50 mL), and a solution of di-tert-butyl dicarbonate (Boc2O, 9.60 g, 44 mmol) in acetonitrile (50 mL) was slowly added. The reaction mixture was stirred at room temperature for 3.5 h. The solvent was removed by concentration under reduced pressure to afford tert-butyl bis(2-hydroxyethyl)carbamate as a colorless oil (8.20 g, 100% yield).
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