Synthesis of 3,4-dihydropyrimidin-2(1H)-one and 3,4-dihydropyrimidin-2(1H)-thione derivatives from aldehydes, 1,3-dicarbonyl derivatives and urea or thiourea using granite and quartz as new, natural and reusable catalysts. Some of the 3,4-dihydropyrimidin-2(1H)-thione derivatives were used to prepare new heterocyclic compounds. The antimicrobial activity of selected examples of the synthesized compounds was tested and showed moderate activity.

T HE Rab23 protein overexpression has a well-validated role in variety of human cancers. Therefore, the present research aimed to identify new Rab23 protein inhibitor candidates using computational based drug design methodology. A novel series of chromeno[2,3-b] pyridine derivatives has been synthesized by the cyclocondensation of 2-amino-3-cyano-4H-chromenes with cyclohexanone and cyclopentanone in ethanolic piperidine solution. The 2-amino-4H-chromenes were obtained using one pot multicomponent condensation of resorcinol, malononitrile and aromatic aldehydes in the presence in ethanolic piperidine solution. All newly synthetic compounds were characterized by spectral analysis IR, NMR and MS and elemental analysis techniques. The best binding modes of chromene derivatives were evaluated via molecular docking studies and binding energy calculations, using PyRx tool. The study has shown that the pyran and pyridine moieties interact favorably with the binding site of target protein, providing the mechanism of action against human sapiens Rab23 protein.

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A new series of thiazolo[3,2-a]pyrimidine bromide salt derivatives 7a–d were synthesized from 3,4-dihydropyrimidinethione precursors. The target compounds were fully characterized by 1D- and 2D-NMR, high resolution ESI-MS/MS and single crystal X-ray diffraction analysis, which confirmed a regioselective 5H cyclization of the dihydropyrimidinethiones. All target compounds were evaluated in vitro as human acetylcholinesterase (hAChE) inhibitors via an Ellman-based colorimetric assay and showed good inhibition activities (better than 70% at 10 µM and IC50 values in the 1 µM range). Molecular docking simulations for all target products into hAChE were performed and confirmed strong binding to the enzyme. These results provide a promising and new starting point to improve acetylcholinesterase inhibitors and explore novel treatment options against Alzheimer’s disease.

Substituted 2-amino-4-aryl-7-hydroxy-4H-chromene-3-carbonitriles (6), 2-amino-4-aryl-4H-benzo[h]chromene-3-carbonitriles (7), and 3-amino-1-aryl-1H-benzo[f ]chromenes-2-carbonitriles (8) were prepared, in good yields, via one-pot three-component reactions of aromatic aldehydes (1), malononitrile (2), and resorcinol (3) or -naphthol (4) or -naphthol (5) in refluxing ethanol or water in the presence of Rochelle salt as novel green heterogeneous and reusable catalyst.