title: Reactions of aminoguanidine with α-dicarbonyl compounds studied by electrospray ionization mass spectrometry.
abstract: Aminoguanidine possesses extensive pharmacological properties. This drug is recognized as a powerful α-dicarbonyl scavenger. In order to better elucidate the reactivity of aminoguanidine with α-dicarbonyls, aminoguanidine was reacted with several aldehydic and diketonic α-dicarbonyls. Electrospray ionization mass spectrometry is a suitable technique to study chemical and biochemical processes, and was selected for the purpose. In aminoguanidine reactions, triazines were detected and, other compounds that have never been reported before were identified. Triazine precursor forms were detected, namely tetrahydrotriazines and singly dehydrated tetrahydrotriazines. Moreover, species with bicyclic ring structures, and dehydrated forms, were also identified in aminoguanidine reactions. These species appear to result from tetrahydrotriazines and triazines reactions with one dicarbonyl molecule. Experiments revealed that these bicyclic species, in particular the ones resulting from triazines reactivity, could exist in solution, since they were both identified in the reactions of aminoguanidine and of a selected triazine with the dicarbonyls studied. The results obtained, regarding aminoguanidine/triazines reactivities, appear to support the capability of triazines to condensate and form polycyclic ring structures, and also to support literature mechanistic data for dihydroimidazotriazines formation via dihydroxyimidazolidine-triazines. The data obtained in this study may prove to be valuable to complement solution information, concerning the reactivity of amines with α-dicarbonyls, in particular.
authors.affiliation: Centro de Química Estrutural, Instituto Superior Técnico, Campus Alameda, Av. Rovisco Pais, Torre Sul, 1049-001 Lisbon, Portugal. masaraiva@fc.ul.pt
authors.forename: Marco A
authors.initials: MA
authors.lastname: Saraiva
authors.forename: Carlos M
authors.initials: CM
authors.lastname: Borges
authors.forename: M Helena
authors.initials: MH
authors.lastname: Florêncio
mesh_terms: D001665:Binding Sites; D002244:Carbon / Q000032:analysis / Q000737:chemistry*; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D006146:Guanidines / Q000032:analysis / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D014227:Triazines / Q000032:analysis / Q000737:chemistry*
chemical_list: D006146:Guanidines; D014227:Triazines; D002244:Carbon; C004479:pimagedine