One-pot synthesis of N-substituted-3-hydroxy-4-pyridinone chelate complexes of aluminum, gallium, and indium

Abstract

Thispaper is dedicated to Professor Ronald J . Gillespie on the occasiorz of his 65th birthday ZAIHUI ZHANG, T. L. THOMAS HUI, and CHRIS ORVIG. Can. J. Chem. 67, 1708Chem. 67, (1989. A series of tris(3-hydroxy-2-methyl-4-pyridinonato)metal(III) and tris(3-hydroxy-6-hydroxymethyl-4-pyridinonat0)-metal(II1) complexes have been prepared in water by one-pot synthesis directly from maltol and kojic acid, respectively, and the metal ion (M = AI, Ga, In) with an appropriate amine. The pyridinones have substituents at the ring nitrogen atom (CH3, C2H5). The tris(3-hydroxy-4-pyronato)metal(III) complexes are formed in situ and these undergo nucleophilic attack by the primary amine; the appropriate tris(3-hydroxy-4-pyridinonato)metal(III) complexes are obtained. This method bypasses the sequential syntheses of ligand and metal complex, and has improved the yields of the tris(1igand)metal complexes, in particular by making them much more easily accessible. The electronic effects of binding the pyrone to the metal ions and of the substituents on the pyrone ring on the reactivity are discussed.Key words: 3-hydroxy-4 pyridinone complexes, group 13 metal ions, one-pot synthesis.ZAIHUI ZHANG, T. L. THOMAS HUI et CHRIS ORVIG. Can. J. Chem. 67, 1708Chem. 67, (1989. Utilisant des reactions de type <<pot au feun impliquant respectivement du maltol et he I'acide kojique, I'ion mCtallique (M = Al, Ga et In) et une amine approprite, on a prCparC une strie de complexes tris(hydroxy-3 hydroxymCthy1-6 pyridinato-4)mCtal(III) dans I'eau. Les pyridinones portent des substituants sur I'atome d'azote du cycle (CH3, CzH5). Les complexes tris(hydroxy-3 pyronato-4)mCtal(III) se forment in situ et ceux-ci subissent une attaque nuclCophile par l'amine primaire; on obtient les complexes tris(hydroxy-3 pyridinonato-4(mCtal(III) appropriCs. La mtthode tvite de passer par les synthkses en sCrie du ligand et du complexe et conduit i de meilleurs rendements des complexes tris(ligand)mttal, en particulier en les rendant beaucoup plus accessibles. On discute de I'influence que les effets Clectroniques de la liaison de la pyrone aux ions mttalliques et des substituants prCsents sur le cycle pyrone peuvent avoir sur la rCactivitC.Mots c c l~s complexes hydroxy-3 pyridinone-4, ions mCtallique du groupe 1 3, synthkse de type << pot au feu s.[Traduit par la revue]

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