Bioorthogonal Tetrazine Carbamate Cleavage by Highly Reactive trans-Cyclooctene

• DOI: 10.1021/jacs.0c00531
• Publication Date: 2020-05-26T20:34:05Z
• Authors: Arthur H. A. M. v...; Ron M. Versteegen; Freek J. M. Hoeben; Ivo A. W. Filot; Raffaella Rossin; Tong Zhu; Jeremy Wu; Peter J. Hudson; Henk M. Janssen; Wolter ten Hoeve; Marc S. Robillard
• Keywords: Tetrazine; Bioorthogonal Chemistry; Conjugate; Cyclooctene; Linker; Carbamate; Reactive intermediate

The high rate of the ‘click-to-release’ reaction between an allylic substituted trans-cyclooctene linker and a tetrazine activator has enabled exceptional control over chemical biological processes. Here we report development new bioorthogonal cleavage based on tetrazine, which allows use highly reactive trans-cyclooctenes, leading to 3 orders magnitude higher click rates compared parent reaction, 4 6 than other reactions. In this pyridazine elimination mechanism, wherein roles are reversed, reacts with that is methylene-linked carbamate, 1,4-elimination carbamate liberation secondary amine. Through series mechanistic studies, identified 2,5-dihydropyridazine tautomer as releasing species found factors govern its formation subsequent fragmentation. utility was demonstrated by selective tetrazine-linked antibody–drug conjugate affording efficient drug in plasma cell culture. Finally, were at low concentration, showing leads complete cycloaddition seconds vs hours for system. Although release from IEDDA adduct slower, believe may allow markedly reduced click-to-release reagent doses vitro vivo could expand application scope conditions limited stability.