Reactivity of a Morita-Baylis-Hillman Adduct Derivative Bearing a Triphenylamine Moiety with Lysine Models

The reactivity of Morita-Baylis-Hillman Adduct (MBHA) derivative 7 was studied with different primary amine derivatives such as n-butylamine, Nα-acetyl-L-lysine methyl ester, and a poly-(L-lysine) derivative as lysine models to obtain information about the possible reactions in complex protein environments. MBHA derivative 7 reacted with n-butylamine or Nα-acetyl-L-lysine methyl ester producing monoadducts 9a or 9c, which showed bright emission features in the green region at 526-535 nm with photoluminescence quantum yield values in solutions of 73 % and 51 %, respectively. Based on these results, MBHA derivative 7 can be considered an interesting new fluorogenic probe potentially useful in the labelling of basic amino acid residues. Furthermore, similar to other MBHA derivatives, compound 7 showed the tendency to produce diadducts especially in polar solvents system where specific interactions between the extended aromatic moieties may play a major role.