Nucleophilic reactivity of biothiols toward coumarin-based derivatives containing a chalcone moiety

作者：Garcia Beltran Olimpo; Gonzalez Christopher; Perez Edwin G; Cassels Bruce K; Santos Jose G; Millan Daniela; Mena Natalia; Pavez Paulina^*; Aliaga Margarita E

来源：Journal of Physical Organic Chemistry, 2012, 25(11): 946-952.

DOI：10.1002/poc.2975

• biothiols
• coumarin-based derivatives
• fluorescent probes
• Michael addition

The Michael addition reactions of the biothiols cysteine (Cys), glutathione (GSH), homocysteine (Hcy) and cysteinylglycine (Cys-Gly) with (E)-3-(3-(2-methoxyphenyl)acryloyl)-7-methoxy-2H-chromen-2-one and (E)-3-(3-(3-methoxyphenyl)acryloyl)-7-methoxy-2H-chromen-2-one (ChC2 and ChC3, respectively) in aqueous solution (25 degrees C, ionic strength 0.2 M KCl) were followed fluorimetrically and evaluated kinetically. With a large excess of biothiol, pseudo-first-order rate coefficients (k(obsd)) were found. Plots of k(obsd) versus [biothiolate] are linear, with a pH-independent slope (k(N)). With the kinetic results obtained, the following conclusions can be drawn: (i) the reactivity increases in the sequence Cys-Gly %26lt; Hcy %26lt; GSH %26lt; Cys; (ii) similar reactivity toward biothiols was found for ChC2 and ChC3, and both probes are more reactive than (E)-3-cinnamoyl-7-methoxy-2H-chromen-2-one (ChC1); (iii) ChC2 and ChC3 display a highly selective fluorescence enhancement with biothiols, allowing these probes to be used for fluorimetric biothiol determination in SH-SY5Y cells.

• 出版日期2012-11