A new approach to the preparation of lanthanide catalysts for the synthesis of 2-propyl-3-ethylquinoline based on the reactions of LnCl3 · 6H2O crystalline hydrates with triisobutylaluminum

A new approach to the preparation of lanthanide catalysts for the synthesis of nitrogen heterocycles (exemplified by 2-propyl-3-ethylquinoline) was developed based on the reactions of LnCl₃ · 6H₂O crystalline hydrates with alkylaluminums. It was found that the interaction of LnCl₃ · 6H₂O (Ln = Ce, Pr, Tb, and Eu) with iso-Bu₃Al in aromatic solvents (20°C) resulted in the formation of soluble (isobutane and the alumoxane (iso-Bu₂Al)₂O) and insoluble products (with the empirical formula LnCl₃ · xH₂O · y(iso-Bu₂Al)₂O (x = 0.4–0.7; y = 0.04–0.07)). The physiochemical properties of LnCl₃ · xH₂O · y(iso-Bu₂Al)₂O were studied, and these compounds were found to be highly efficient catalysts for the reaction of aniline condensation with butyraldehyde to form 2-propyl-3-ethylquinoline.     

Interaction of LnCl3 · 6H2O crystal hydrates with the alkoxy derivatives of aluminum in organic solvents

The interaction of LnCl₃ · 6H₂O (Ln = Pr, Nd, and Tb) with the alkoxy derivatives of aluminum (RO)_nAlCl_3?n (where R = Et or iso-Bu; n = 1–3) in organic solvents was studied. It was found that the reaction of the crystal water of LnCl₃ · 6H₂O with (RO)_nAlCl_3?n resulted in the partial dehydration of the crystal hydrates with the formation of an alcohol (ROH) and the LnCl₃ · 3H₂O · 3(RO)_mAl(OH)Cl_2?m complex (m = 1, 2). The solid colloidal particles of this complex and a solvent form a lanthanide-containing gel. The physicochemical (including luminescence) and catalytic properties of the complex in butadiene polymerization and 1,1-gem-dibromo-2-phenylcyclopropane dehalogenation were studied.     

Catalytic activity of iron(III), aluminum(III), cobalt(II), and magnesium(II) chloride crystal hydrates in the condensation of aniline with butyraldehyde

Russian Journal of Organic Chemistry -