Description
Fmoc-Val-Cit-PAB-OH is a cleavable ADC linker. The Val-Cit will specifically be cleaved by Cathepsin B. As this enzyme is only present in the lysosome, the ADC payload will be released only in the cell. Fmoc can be deprotected under basic condition.
Synthesis
The general procedure for the synthesis of the target compound (CAS:159858-22-7) from (S)-2-((S)-2-((((9H-fluoren-9-yl)methoxy)carbonyl)amino)-3-methylbutanoylamino) and p-aminobenzenemethanol (PABOH) was carried out as follows: 60 ml of dichloromethane (DCM) mixed with methanol (MeOH) in the ratio of 2:1, by volume of the Solvent was added to the reaction flask, followed by 4.2 mmol Fmoc-vc2g and 1.04 g (2 eq.) of PABOH. after stirring until complete dissolution, 2.0 g (2 eq.) of EEDQ was added. the reaction system was protected from light at room temperature, and the reaction was continuously stirred for 2.0 days. After completion of the reaction, the reaction mixture was concentrated under reduced pressure at 40 °C to give a white solid. The white solid was collected, 100 ml of methyl tert-butyl ether (MTBE) was added, stirred and filtered, and the filter cake was washed with methyl tert-butyl ether. The resulting white solid was dried under reduced pressure at 40 °C to give 2.2 g of the target product in about 88% yield.
References
[1] International Journal of Molecular Sciences, 2017, vol. 18, # 9,
[2] Patent: CN107789630, 2018, A. Location in patent: Paragraph 0073; 0074; 0075
[3] Patent: WO2017/66668, 2017, A1. Location in patent: Paragraph 000187-000189
[4] Journal of Controlled Release, 2012, vol. 160, # 3, p. 618 - 629
[5] Patent: KR2017/41562, 2017, A. Location in patent: Paragraph 0431-0432
