863971-53-3

Fmoc-Val-Cit-PAB-PNP is a a cleavable ADC linker used in antibody drug conjugate. The Val-Cit linker was designed to be cleaved by cathepsin B. PNP group is a good leaving group when reacting with amine bearing payload.

Fmoc-Val-Cit-PAB-PNP is a cleavable ADC linker used in the synthesis of antibody-drug conjugates (ADCs). Fmoc-Val-Cit-PAB-PNP has superior plasma stability comparable to that of non-cleavable linkers[1][2][3].

Fmoc-Val-Cit-PAB-PNP is a cleavable ADC linker that can be used to synthesize antibody drug conjugates (ADCs).

General procedure for the synthesis of compound (CAS:863971-53-3) from bis(4-nitrophenyl) carbonate and compound (CAS:159858-22-7): under nitrogen protection, N-[(9H-fluoren-9-ylmethoxy)carbonyl]-L-valyl-N5-carbamoyl-N-[4-(hydroxymethyl)phenyl]-L-ornithinamide ( 1.3 g, 2.16 mmol, prepared as reported in EP0624377A2) was dissolved in 6 mL of anhydrous DMF with bis(4-nitrophenyl) carbonate (1.32 g, 4.34 mmol). After addition of DIPEA (0.75 mL, 4.35 mmol), the reaction mixture was stirred at room temperature for 1 hour. After completion of the reaction, diethyl ether (120 mL) was added to precipitate the product, and the precipitate was collected by filtration, washed with diethyl ether, and dried under vacuum to afford N-[(9H-fluoren-9-ylmethoxy)carbonyl]-L-valyl-N5-carbamoyl-N-[4-({{[(4-nitrophenoxy)carbonyl]oxy}methyl)phenyl]-L-ornithinamide (1.47 g, yield 89%). ESI MS: m/z 767 (MH+). 1H NMR (400MHz, DMSO-d6) δ 0.86 (d, J=6.7Hz, 3H), 0.88 (d, J=6.7Hz, 3H), 1.30-1.52 (m, 2H), 1.60 (m, 1H), 1.69 (m, 1H), 1.99 (m, 1H ), 2.90-3.10 (m, 2H), 3.93 (dd, J=8.9,7.0Hz, 1H), 4.14-4.34 (m, 3H), 4.42 (m, 1H), 5.24 (s, 2H), 5.39 (s, 2H), 5.97 (t, J=5.5Hz, 1H), 7.32 (m, 2H), 7.42 (m, 5H ), 7.55 (m, 2H), 7.65 (d, J=8.4Hz, 2H), 7.74 (t, J=7.9Hz, 2H), 7.88 (d, J=7.6Hz, 2H), 8.12 (d, J=7.4Hz, 1H), 8.31 (m, 2H), 10.12 (s, 1H).

Protease Cleavable Linker; Cleavable Linker

[1] Dubowchik GM, et al. Cathepsin B-labile dipeptide linkers for lysosomal release of doxorubicin from internalizing immunoconjugates: model studies of enzymatic drug release and antigen-specific in vitro anticancer activity. Bioconjug Chem. 2002 Jul-Aug;13(4):855-69. DOI:10.1021/bc025536j
[2] Yoneda Y, et al. A cell-penetrating peptidic GRP78 ligand for tumor cell-specific prodrug therapy. Bioorg Med Chem Lett. 2008 Mar 1;18(5):1632-6. DOI:10.1016/j.bmcl.2008.01.060
[3] Dorywalska M, et al. Effect of attachment site on stability of cleavable antibody drug conjugates. Bioconjug Chem. 2015 Apr 15;26(4):650-9. DOI:10.1021/bc5005747