title: Transformations of the natural cytokinin N6-isopentenyladenine in aqueous acidic media: structural aspects.
abstract: N6-Isopentenyladenine (L1) was subjected to variously acidic media in 0.1 M, 1 M and 2 M HCl. In dependence on the acidity of the medium, the formation of three main acid hydrolysis products, involving the N6-isopentenyladeninium (HL1) (1), 7,8,9,10-tetrahydro-7,7-dimethyl-3H-pyrimido[2,1-i]purin-6-ium (HL2) (2) or 5-amino-4-(4,4-dimethyl-3,4,5,6-tetrahydropyrimidin-2-yl)-imidazolium (H(2)L3) (3-5) cations, were determined and characterized by multinuclear solution-state NMR spectroscopy and in the solid state by single crystal X-ray analysis. The coordination abilities of these transformation products have been also investigated. The compounds of the compositions [Zn(HL1)Cl(3)]·H(2)O (1), [Zn(3)(HL2)(2)Cl(8)] (2), (H(2)L3)[CuCl(4)] (4) and (H(2)L3)[ZnCl(4)] (5) have been prepared in dependence on the acidity of the medium used by the reactions of L1 with ZnCl(2)·1.5H(2)O or CuCl(2)·2H(2)O. Based on the NMR spectroscopic and X-ray crystallographic results, the mechanism of transformation of L1 in the acidic medium, involving the protonation, cyclization and ring fission, has been suggested.
authors.affiliation: Regional Centre of Advanced Technologies and Materials, Department of Inorganic Chemistry, Faculty of Science, Palacký University, Olomouc, Czech Republic. zdenek.travnicek@upol.cz
authors.forename: Zdeněk
authors.initials: Z
authors.lastname: Trávníček
authors.forename: Radka
authors.initials: R
authors.lastname: Novotná
authors.forename: Jaromír
authors.initials: J
authors.lastname: Marek
authors.forename: Igor
authors.initials: I
authors.lastname: Popa
authors.forename: Michal
authors.initials: M
authors.lastname: Sipl
mesh_terms: D000143:Acids / Q000737:chemistry; D018360:Crystallography, X-Ray; D003583:Cytokinins / Q000737:chemistry*; D006868:Hydrolysis; D007541:Isopentenyladenosine / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D014867:Water / Q000737:chemistry
chemical_list: D000143:Acids; D003583:Cytokinins; D014867:Water; C001478:N(6)-(delta(2)-isopentenyl)adenine; D007541:Isopentenyladenosine