Orthophthalaldehyde (OPA) is used in analytical and biologically significant reactions for many years due to its specific reactivity with N-, S- and O- nucleophiles [1,2]. Besides the analytical method for determination of amino acids, the solution of OPA is broadly applied in hospitals as a disinfecting agent for surgery instruments made from plastics. In the literature, there is a simplified "traditional" description of main products and the expected mechanism related to the applications, however, our recent systematic research in this field revealed several unobserved phenomena showing that the mechanisms are not understood [3,4].

Due to the ortho-position of the two carbonyls, OPA contains a system of two communicating redox centers exhibiting very specific reactivity. The main feature of the OPA behavior is ability to fast intramolecular cyclization of primary intermediates of classic addition and condensation reactions of a carbonyl with a nucleophile. As a consequence, the reaction mechanism and formation of products strongly depends on the structure of the nucleophile itself, since the cyclization and inter-as well as intramolecular follow-up reactions offer a number of structural and stoichiometric possibilities.

In the present report (spectro)electrochemical monitoring of the reactions of OPA with various types of nucleophiles (water which is, in fact, the most abundant nucleophile in the system, primary amines, 1,2- and a,ω-diamines derived from aromatic, aliphatic or alicyclic species, amino acids, thiols and various molecules containing two different nucleophilic centers) will be discussed and the mechanistic conclusions will be supported by identification of products by MS, NMR and x-ray structural analyses [5-9].

Acknowledgments

The research was supported by GA CR (project No. 17-18108S) and by institutional support (RVO: 61388955).

References

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10. Kristallogr. 2017, DOI: https://doi.org/10.1515/zkri-2016-2001

[9] Donkeng Dazie, J.; Liška, A.; Urban, J.; Ludvík, J. J. Electroanal. Chem. – submitted 2017.