Pd Doped on TCH@SBA-15 Nanocomposites: Fabrication and Application as a New Organometallic Catalyst in the Three-Component Synthesis of N-Benzo-imidazo- or -thiazole-1,3-thiazolidinones

In this study, Pd(II)/TCH@SBA-15 nanocomposites were synthesized by the grafting of 3-chloropropyltriethoxysilane and thiocarbohydrazide on SBA-15 and subsequent deposition of palladium acetates through the ligand-metal coordination method. The structure and morphology of this nanoporous nanocomposite was thoroughly identified by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, thermogravimetric analysis, atomic absorption spectroscopy, and Brunauer-Emmett-Teller instrumental analyses. Furthermore, the catalytic activity of this nanocomposite was investigated in the three-component synthesis of 3-benzimidazolyl or benzothiazoleyl-1,3-thiazolidin-4-ones via a reaction of 2-aminobenzimidazole or 2-aminobenzothiazole, aromatic aldehydes, and thioglycolic acid in an acetone-H2O mixture under green conditions. The Pd/TCH@SBA-15 nanocatalyst is demonstrated to exhibit a high catalyzing activity in the three-component reaction of the synthesis of N-heterocyclic thiazolidinones with good to excellent yields. One of the advantages of the suggested method is the direct application of the thiocarbohydrazide ligand to stabilize Pd nanoparticles through formation of a stable ring complex without creating an additional Schiff base step. Moreover, this organometallic nanocatalyst can be recycled several times with no notable leaching or loss of performance.

Multicomponent reaction for the synthesis of new 1,3,4-thiadiazole-thiazolidine-4-one molecular hybrids as promising antidiabetic agents through α-glucosidase and α-amylase inhibition

A simple and efficient protocol was developed to synthesize a new library of thiazolidine-4-one molecular hybrids (4a-n) via a one-pot multicomponent reaction involving 5-substituted phenyl-1,3,4-thiadiazol-2-amines, substituted benzaldehydes and 2-mercaptoacetic acid. The synthesized compounds were evaluated in vitro for their antidiabetic activities through α-glucosidase and α-amylase inhibition as well as their antioxidant and antimicrobial potentials. Compound 4e exhibited the most promising α-glucosidase and α-amylase inhibition with an IC₅₀ value of 2.59 μM, which is ~1.5- and 14-fold superior as compared to the standard inhibitor acarbose. Structure-activity relationship (SAR) analysis revealed that the nature and position of substituents on the phenyl rings had a significant effect on the inhibitory potency.

Design of a new multi-functional catalytic system Ni/SO3H@zeolite-Y for three-component synthesis of N-benzo-imidazo- or -thiazole-1,3-thiazolidinones

In this investigation, a nanoporous zeolite-NaY supported sulfonic acid was synthesized and Ni(ii) ions were successfully stabilized on SO₃H@zeolite-Y (Ni/SO₃H@zeolite-Y). This novel type of zeolitic nanocomposite was characterized using various techniques including FT-IR, FE-SEM, TGA, BET and EDX. Ni/SO₃H@zeolite-Y was used as a multi-functional and highly active nanocatalyst for the three-component synthesis of 3-benzimidazolyl-1,3-thiazolidin-4-ones and new 3-benzthiazoleyl-1,3-thiazolidin-4-ones via cyclocondensation of 2-aminobenzimidazole or 2-aminobenzothiazole, aromatic aldehydes and thioglycolic acid in acetone-H₂O at room temperature. This economical chemical procedure has advantages such as excellent yield in short reaction times, convenient manipulation and high purity of products, applicability to a broad range of substrates, and the use of a nontoxic and heterogeneous acid catalyst with good reusability.

SO3H-functionalized Zeolite-Y as an Efficient Nanocatalyst for the Synthesis of Nbenzimidazole- 2-aryl-4-thiazolidinones and tri-substituted Imidazoles

BACKGROUND

SO3H-functionalized zeolite-Y was prepared and used as a catalyst for the synthesis of 2-aryl-N-benzimidazole-4-thiazolidinones and tri-substituted imidazoles at ambient conditions.

OBJECTIVE

The goals of this catalytic method include excellent yields and high purity, inexpensive procedure and ease of product isolation, the use of nontoxic and heterogeneous acid catalyst, shorter reaction times and milder conditions.

MATERIALS AND METHODS

NMR spectra were recorded on Brucker spectrophotometer using Me4Si as internal standard. Mass spectra were recorded on an Agilent Technology 5975C VL MSD with tripe-axis detector. FTIR spectra were obtained with KBr disc on a galaxy series FT-IR 5000 spectrometer. The surface morphology of nanostructures was analyzed by FE-SEM (EVO LS 10, Zeiss, Carl Zeiss, Germany). BET analysis were measured at 196 °C by a Japan Belsorb II system after the samples were vacuum dried at 150°C overnight.

RESULTS

The NSZ was characterized by FT-IR, FESEM, EDX, XRF, and BET. The catalytic activity of NSZ was investigated for synthesis of 1,3-tiazolidin-4-ones in H2O/Acetone at room temperature. Moreover, NSZ was used for synthesis of tri-substituted imidazoles at 60 °C via solvent-free condensation. Different kinds of aromatic aldehydes were converted to the corresponding of products with good to excellent yields.

CONCLUSION

Sulfonated zeolite-Y was as an efficient catalyst for the preparation of N-benzimidazole-2-aryl-1,3- thiazolidin-4-ones and 2,4,5-triaryl-1H-imidazoles. High reaction rates, elimination toxic solvent, simple experimental procedure and reusability of the catalyst are the important features of this protocol.