Method for labeling of aldehyde containing target molecules

The present description relates to a method for binding to a target molecule having an aldehyde compound derived from N-(2-aminoethyl)pyrrole, which compound also has a moiety of interest, to compounds (conjugates) obtained by this method, having both the target molecule and the moiety of interest and to novel substances derived from N-(2-aminoethyl)pyrrole. In one embodiment, the compound has the formula of Formula IIwherein R1, R2 and R3 independently are H, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, or substituted or unsubstituted heteroaryl, wherein R4, R5, R6, R7 and R8 independently are H, substituted or unsubstituted alkyl, substituted or unsubstituted heteroalkyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, or -LM, wherein L is absent or is a linker and M is a moiety of interest selected from a nucleotide, an oligonucleotide, a peptide, a label, a cytotoxic agent, a partner of a binding pair and a functional group, wherein two of R4, R5, R6, R7, and R8 optionally are linked to form a substituted or unsubstituted cycloalkyl or a substituted or unsubstituted heterocycloalkyl, and T is a target molecule selected from the group consisting of a solid phase, a polypeptide, a protein, a carbohydrate, a nucleotide and a nucleic acid, with the proviso that at least one of R4, R5, R6, R7 or R8 is -LM.