Description
Hydroxy-PEG3-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.
Biological Activity
Tert-Butyl-12-hydroxy-4,7,10-trioxadodecanoate is an ADC linker for the synthesis of antibody drug conjugates (ADC), it is derived from patent WO2004008101A2 (compound 196). It can also be used as a PROTAC linker for PROTAC synthesis. .
Synthesis
Synthesis of Compound 71; Step a: Sodium metal (0.10 g, 4.35 mmol) was slowly added to an anhydrous tetrahydrofuran (250 mL) solution of triethylene glycol (64.0 mL, 0.48 mol) at room temperature. After the sodium was completely dissolved, tert-butyl acrylate (24.0 mL, 0.164 mol) was added dropwise to the system. The reaction mixture was stirred continuously at room temperature for 20 h. The reaction was subsequently neutralized with 1.0 N hydrochloric acid solution (4 mL). After removal of the solvent by distillation under reduced pressure, the residue was suspended in saturated aqueous sodium chloride solution and extracted with ethyl acetate (3 x 70 mL). The organic phases were combined, washed with saturated aqueous sodium chloride solution and dried over anhydrous magnesium sulfate. After concentration under reduced pressure to remove the solvent, the tert-butyl acrylate adduct (40.23 g, 0.157 mol, 96% yield) was obtained as a colorless oil, which could be used for subsequent reactions without further purification. The product was analyzed by high performance liquid chromatography (HPLC): retention time t R = 10.2 min.
References
[1] Patent: US2006/228325, 2006, A1. Location in patent: Page/Page column 63
[2] Patent: CN105524053, 2016, A. Location in patent: Paragraph 0468; 0469; 0470
[3] Journal of Organic Chemistry, 1997, vol. 62, # 4, p. 813 - 826
[4] Organic and Biomolecular Chemistry, 2015, vol. 13, # 1, p. 81 - 97
[5] Patent: US9301951, 2016, B2. Location in patent: Page/Page column 295
