Description
Hydroxy-PEG2-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.
Uses
Hydroxy-PEG2-(CH2)2-Boc is an ADC linker for the synthesis of antibody drug conjugates (ADC), Hydroxy-PEG2-(CH2)2-Boc is derived from patent WO2004008101A2 (compound 196). Hydroxy-PEG2-(CH2)2-Boc can also be used as a PROTAC linker for PROTAC synthesis.
Synthesis
Example 1: Synthesis of tert-butyl 3-(2-(2-hydroxyethoxy)ethoxy)propionate (84)
In 350 mL of anhydrous tetrahydrofuran (THF), 80 mg (0.0025 mol) of sodium metal and diethylene glycol (150.1 g, 1.41 mol) were added and stirred until the sodium metal was completely dissolved. Subsequently, tert-butyl acrylate (24 mL, 0.33 mol) was added. The reaction mixture was stirred at room temperature for 20 h. After completion of the reaction, it was neutralized with 8 mL of 1.0 M hydrochloric acid (HCl). The solvent was removed by distillation under reduced pressure and the residue was suspended in 250 mL of brine and extracted with ethyl acetate (3 x 125 mL). The organic layers were combined, washed sequentially with 100 mL of brine and 100 mL of water, dried over anhydrous sodium sulfate, and the solvent was removed under reduced pressure. The resulting colorless oil was dried under vacuum to give 60.27 g (78% yield) of the target product 84.
Product Characterization:
1H NMR (CDCl3): δ 1.41 (s, 9H), 2.49 (t, 2H, J = 6.4 Hz), 3.59-3.72 (m, 10H).
ESI MS m/z: [M-H]- calcd for C11H21O5, 233.15; found, 233.40.
in vitro
ADCs are comprised of an antibody to which is attached an ADC cytotoxin through an ADC linker.
IC 50
Non-cleavable Linker; PEGs; Alkyl/ether
References
[1] Synthesis (Germany), 2014, vol. 46, # 10, p. 1399 - 1406
[2] Patent: WO2015/155753, 2015, A2. Location in patent: Page/Page column 84
[3] Journal of the American Chemical Society, 2011, vol. 133, # 10, p. 3230 - 3233
[4] Synthetic Communications, 2004, vol. 34, # 13, p. 2425 - 2432
[5] Patent: WO2018/2902, 2018, A1. Location in patent: Page/Page column 46
