Efficient and recoverable novel pyranothiazol Pd (II), Cu (II) and Fe(III) catalysts in simple synthesis of polyfunctionalized pyrroles: Under mild conditions using ultrasonic irradiation

Abstract

Three novel Pd (II), Cu (II), and Fe (III) complexes were prepared from thiazole ligand through bidentate chelating mode. Alternative spectral and analytical tools were applied to elucidate their structural and molecular formulae. This study was extended to investigate stability and stoichiometry of complexes in solution, using standard methods. In addition, the best atomic distribution within structural forms was obtained by Material Studio Package via the density functional theory (DFT) method. This computational study fed us with significant physical characteristics for differentiation. Also, crystal surface properties in the packing system were studied using the Crystal explorer program, to evaluate the extent of contact between surfaces. Computational data discriminate Pd (II)-thiazole (HYHPd) complex by some physical features, which may be promising in the catalytic field. This complex was selected to play a catalytic function to synthesize polyfunctionalized pyrrole derivatives using ultrasonic irradiation in a one-pot reaction. The catalyst was selected for this application based on the history of Pd (II) complexes and the properties expected theoretically. A condensation reaction for aromatic aldehyde, aromatic amine, acetylacetone, and nitromethane was carried out under mild reaction conditions by ultrasonic irradiation. All reaction conditions were optimized among that variable Lewis acid catalysts in comparison to our new complexes. HYHPd catalyst displayed superiority in overall trials with high yield, short time, and green conditions (solvent H 2 O/EtOH). Also, the recovery of hetero-catalyst was succeeded and reused by the same efficiency up to five times after that the efficiency was reduced. The mechanism of action was proposed based on the ability of Pd (II) for adding extra-bonds over z axis and supported by theoretical aspects.

Design, preparation, physicochemical characterization, structural conformational, biological evaluation, and DNA interaction for some new benzimidazole complexes

“…The detailed molecular ion [M + ] peaks of the tested chelates were applied to approve the recommended formula. MS of BIPCu, BIPPd, BIPVO, and BIPAg chelates are agreed upon to conclude its molecular mass as well as proposed fragmentation shape as elucidated in Figure 2 as well, hence identify the elemental study as well as spectral results 30 . MS of BIPCu complex presented a [M + ] at m/z = 474.50 amu that confirms the suggested structure [C 17 H 25 N 5 O 6 Cu; M. wt = 474.50 g/mol].…”

“…The signals have been assigned between 7.61:7.09 ppm because of the (Ar–H) in the BIP ligand. The signals around (2.42) ppm agree to the 2(–CH 3 ) attached to the pyrimidine ring 16b,30,46 …”

“…Cyanoguanidine (10 mmol) in a mixture of (1 HCl: 3 H 2 O) has been added to a prepared solution of o‐phenylenediamine (10 mmol) in a mixture of (1 HCl: 3 H 2 O) and then refluxed until complete the reaction for 4 h, the resulting solution cooled and treated with NaOH (20%) till the first precipitate (A) (2‐guanidinobenzimidazole) is formed, washed, filtrated, and dried, as elucidate in earlier study 30 . After that the obtained product refluxed with acetyl acetone with 5–6 drops of glacial CH 3 COOH as well as the development of the reaction was tested repeatedly with TLC.…”

Azide‐Alkyne Cycloaddition Reaction Catalyzed by Cu(II) Complexes: Studies on the effect of Different Ligand Systems

“…The catalytic results obtained with the complex are much better than the in situ reaction. Reactions were also compared with the reported literature and it is comparable [30–32] …”

Recent Advances in the Synthesis of Five‐membered Nitrogen Heterocycles Induced by Palladium Ions and Complexes

“…Reactions, executed under ultrasonic treatment, afforded excellent yields in rapid reactions (Scheme 12). [24] Moreover, the catalyst showed high stability in a seven‐run reuse study (99–95 %, 97 % avg. yield).…”