Efficient and Recoverable Bio-Organic Catalyst Cysteine for Synthesis, Docking Study, and Antifungal Activity of New Bio-Active 3,4-Dihydropyrimidin-2(1H)-ones/thiones Under Microwave Irradiation.

An eco-friendly green bio-organic catalyst and low-cost 3,4-dihydropyrimidin-2(1H)-ones/thione derivatives 4-7 have been synthesized using a high-yield, synthetic method via a one-pot, three-component process between 4-formylphenyl-4-methylbenzenesulfonate (1), thiourea, or urea and ethyl acetoacetate or acetylacetone under microwave irradiation in aqueous media of water and ethanol (3:1 ratio) as a green solvent in the presence of cysteine as a new green bio-organic catalyst. The reaction between compound 1, 4-(carbamothioylhydrazono) methyl]phenyl 4-methyl benzenesulfonate (3c), and ethyl acetoacetate or acetylacetone under the same condition afforded novel pyrimidines. Similarly, compound 1 was allowed to react with a mixture of 4-(carbamothioylhydrazono)methyl]phenyl 4-methyl benzenesulfonate (3c) and ethyl acetoacetate or acetylacetone under the same condition to afford pyrimidine derivatives 8 and 9. Excellent yields (90-98%) were obtained within short reaction times, and problems associated with the toxic solvents used (cost, safety, and pollution) were avoided. The structures of the new compounds were elucidated by elemental and spectral analyses. All compounds were studied using molecular docking, and their antifungal activity was investigated.

Development of New Thiazole Complexes as Powerful Catalysts for Synthesis of Pyrazole-4-Carbonitrile Derivatives under Ultrasonic Irradiation Condition Supported by DFT Studies.

In this study, we are interested in preparing Fe(III), Pd(II), and Cu(II) complexes from new thiazole derivatives. All syntheses were elaborately elucidated to estimate their molecular and structural formulae, which agreed with those of mononuclear complexes. The square-planer geometry of Pd(II) complex (MATYPd) was the starting point for its use as a heterocatalyst in preparing pyrazole-4-carbonitrile derivatives 4a-o using ultrasonic irradiation through a facile one-pot reaction. The simple operation, short-time reaction (20 min), and high efficiency (97%) were the special advantages of this protocol. Furthermore, this green synthesis strategy was advanced by examination of the reusability of the catalyst in four consecutive cycles without significant loss of catalytic activity. The new synthesis strategy presented remarkable advantages in terms of safety, simplicity, stability, mild conditions, short reaction time, excellent yields, and use of a H2O solvent. This catalytic protocol was confirmed by the density functional theory (DFT) study, which reflected the specific characteristics of such a complex. Logical mechanisms have been suggested for the successfully exerted essential physical parameters that confirmed the superiority of the Pd(II) complex in the catalytic role. Optical band gap, electrophilicity, and electronegativity features, which are essential parameters for the catalytic behavior of the Pd(II) complex, are based mainly on the unsaturated valence shell of Pd(II).

Green Method for the Synthetic Ugi Reaction by Twin Screw Extrusion without a Solvent and Catalyst.

This study describes the solvent and catalyst-free Ugi reaction by way of twin screw extrusion (TSE). Multicomponent chemical synthesis can be converted into a single process without repeated use of solvents through TSE. High synthetic yields are achieved in short reaction times and produced in solvent-free conditions, which lead to a more environmentally friendly process.