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

Abstract

ABSTRACT. 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.

A novel samarium complex with interesting photoluminescence and semiconductive properties

“…Recently, 4,4′-bipyridine (bipy) with delocalized -electrons of the pyridyl rings obtains increasing attention in preparing light emitting complexes in different technical applications, such as emitting materials for organic light emitting diodes, sensitizers in solar energy conversion, chemical sensors and so forth [6][7][8][9]. The ability of bipy to act as a rigid, rod-like organic building block in the self-assembly of coordination frameworks is well-known, such as, acting as a charge-compensating cation, a pillar bonding to inorganic skeletal backbone, an uncoordinated guest molecule and organic template, a bridge connecting two metal complex moieties, or linking a metal and an inorganic framework [10][11][12]. Comparing with the neutral 4,4'-bipy, 4,4'-Hbipy cation is easier to form supramolecular frameworks through H-bonding.…”

Theoretical and experimental investigations into the structural, electronic, and molecular properties of 1,5-dihydropyrano[2,3-c]chromene derivatives

“…Following our previous works on environmentally friendly multi-component reaction [21][22][23], we synthesized a series of 1,5dihydropyrano[2,3-c]chromene derivatives (4a-i) by threecomponent reaction of aromatic aldehydes (1), 3hydroxycoumarin (2) and malononitrile (3) in the presence of piperidine as base in EtOH, under reflux conditions (Scheme 1).…”

Controlled Modification of Triaminoguanidine-Based μ3 Ligands in Multinuclear [VIVO]/[VVO2] Complexes and Their Catalytic Potential in the Synthesis of 2-Amino-3-cyano-4H-pyrans/4H-chromenes

“…Such diverse biological, pharmaceutical, and medicinal uses of pyran-annulated heterocyclic molecules have drawn the attention of chemists to develop novel synthetic ways for the preparations of these medicinally important pyran derivatives. Therefore, several approaches have been described earlier; however, the most effective and straightforward methods are those that involve the one-pot, three-component reaction between aryl aldehyde, malononitrile, and C–H-activated compounds (like dimedone, 1,3-cyclohexanedione, and barbituric acid) using different homogeneous/heterogeneous catalysts. − Although the catalytic multicomponent synthesis of pyrans reported in the literature has its own advantages, it still has some drawbacks including extended reaction periods, unfavorable reaction conditions, costly catalyst, high requirement of catalyst, and formation of side products. However, searching for a more efficient, green, highly economical, and high-yielding route, which requires a low catalyst amount, remains a valid exercise.…”