METHODS FOR THE PREPARATION OF LINKER PAYLOAD CONSTRUCTS

The present invention concerns a method for the preparation of an alkyne-linker-payload construct of structure Q-L-C(O)-NR3-D (1), comprising reacting (i) an alkyne compound of structure Q-L-C(O)-X (2), wherein Q is an alkyne moiety selected from the group consisting of terminal alkyne and (hetero)cycloalkyne; L is a linker, and X is a leaving group selected from halogen, SR1, O-succinimidyl, O-(hetero)aryl(R2)1-5, wherein R1 is selected from C1-C6 alkyl and (hetero)aryl; and R2 is C1-C6 alkyl, halogen or NO2; with (ii) a molecule of structure D-NHR3 (3), wherein D is a payload, and R3 is selected from hydrogen, optionally substituted C1-C24 alkyl, optionally substituted aryl. The activated ester derivatives (2) are highly stable and provide for smooth and high-yielding attachment to a cytotoxic payload. The invention further concerns a method for preparing bioconjugates and alkyne compound of structure Q-L-C(O)-X (2).