Two ligand oxidio-vanadium(IV) complexes as novel efficient catalysts in multicomponent reactions for synthesis of tetrahydrobenzopyran derivatives

Two ligand oxido-vanadium(IV) complexes, [VO(L)(bipy)] (Ι) and [VO(L)(phen)] (ΙΙ); [H2L: 4-bromo-2-(((5-chloro-2-hydroxyphenyl)imino)methyl)phenol, bipy: 2,2’-bipyridine and phen: 1,10-phenanthroline], have been synthesized and characterized by elemental analysis, FT-IR, UV-Vis and conductivity measurements. These complexes, as new catalysts, were also used to synthesize the tetrahydrobenzopyran derivatives by three-component reaction of cyclic β-dicarbonyl compounds, malononitrile and aromatic aldehydes, in EtOH, at reflux. Inexpensiveness, stability and the potential of being easily obtained can be noted as preponderance of these catalysts. Furthermore, high conversions, short reaction times and cleaner reaction profiles, are some of the advantages of this method. These catalysts can be recovered and reused several times without loss of activity.

Oxido-vanadium(IV) complex, Tetrahydrobenzopyran derivatives, Three-component reaction, Cyclic β-dicarbonyl compounds, Malononitrile