Silica-bonded S-sulfonic Acid as a Recyclable Catalyst for Synthesis of 2,3-Dihydroquinazolin-4（1H）-ones

2,3-Dihydroquinazolin-4（1H）-one derivatives were synthesized via a one-pot, three component reaction of isatoic anhydride and an aromatic aldehyde with ammonium acetate or primary amine catalyzed by silica-bonded S-sulfonic acid in ethanol at 80 ℃. The reaction work-up is simple and the catalyst is easily separated from the products by filtration. The heterogeneous catalyst was recycled for ten runs upon the condensation reaction of isa- toic anhydride and 4-chlorobenzaldehyde with ammonium acetate without losing its catalytic activity.

Synthesis of some new bis-3,4-dihydropyrimidin-2(1H)-ones by using silica-supported tin chloride and titanium tetrachloride

Silica-supported tin chloride and titanium tetrachloride were prepared by the reaction of tin chloride and titanium tetrachloride with activated silica gel in refluxing toluene.These solid acids have been employed as the catalysts for the synthesis of bisdihydropyrimidin -2(1H)-ones from aromatic dialdehydes,1,3-dicarbonyl compounds and urea at 90℃under solvent-free conditions.

Synthesis, anti-fibrosis activity, and quantitative structure-activity relationship studies of 1,3-disubstituted-pyridin-4(1H)-one derivatives

A series of 1,3-disubstituted-pyridin-4（1H）-one derivatives were synthesized. The results of a viability assay on NIH_T3 cells indicated that compound 3m potently inhibited the cell viability with an IC50 value of 2.0 μM. The 3D-quantitative structure-activity relationship analyses of 30 final molecules applying topomer CoMFA and AutoGPA methods gave two reasonable models with a cross-validated correlation coefficient q^2 of 0.662 and 0.787, respectively. The achievement herein suggested the application of 3-hydroxypyridin-4（1H）-one as a novel scaffold for the discovery of anti-fibrosis agents. In addition, the QSAR and pharmacophore models established with the activity data may provide new insights into the structure optimization of pyridin-4（1H）-one derivative with potent anti-fibrotic effects.

Synthesis of 2,3-dihydroquinazolin-4(1H)-ones catalyzed by zirconium(Ⅳ) chloride as a mild and efficient catalyst

2,3-Dihydroquinazolin-4（1H）-ones have been synthesized in the high to excellent yields via condensation of 2-aminobenzamide with aldehydes and ketones in the presence of catalytic amount of ZrCl_4 in EtOH at room temperature.Mild reaction conditions, clean reaction media,simple workup and easy purification are advantages of this methodology.

Eco-friendly and Efficient Synthesis of 2,3-Dihydroquinazolin-4（1 H）-ones

A simple and facile method for the synthesis of 2,3-dihydroquinazolin-4（1H）-ones through the direct cyclocon- densation of one-pot three-component cyclocondensation of isatoic anhydride, ammonium acetate （or primary amines） and aldehydes; and anthranilamide and aldehydes using silica supported ferric chloride （SiO2-FeCl3） as catalyst under solvent-free conditions is described.

Catalytic activity of TiO_2 nanoparticles in the synthesis of some2,3-disubstituted dihydroquinazolin-4(1H)-ones

Green chemistry is playing an important role for synthesizing organic compounds, due to its eco-friendly nature and low cost. In green chemistry, metal nanoparticles exhibited some useful physical and chemical properties （catalytic activity）. Due to its diverse properties, nanoparticles can be utilized as a catalyst in various organic reactions. Recent research has been directed towards the utilization of eco- friendly and bio-friendly plant materials in nanoparticles synthesis. In our present work, TiO2 nanoparticles （TiO2 NPs） were synthesized using Annona squamosa peel extract and their catalytic applications were studied on the 2,3-disubstituted dihydroquinazolin-4（l1H）-one synthesis. Synthesized compounds were confirmed using FT-IR.1H NMR, 13C NMR and GC-MS analyses.

Practical approach to 2-thioxo-2,3-dihydroquinazolin-4(1H)-one via dithiocarbamate–anthranilic acid reaction

A practical and straightforward protocol has been developed for the preparation of 2-thioxo-2,3-dihydroquinazolin-4（1H）-one derivatives from dithiocarbamate chemistry. The method involves the reaction of anthranilic acid derivatives（2-aminobenzoic acid, 2-aminobenzamide and isatoic anhydride）with various dithiocarbamate derivatives using ethanol as solvent. The main advantages of this protocol include practical simplicity, good to high yields, and ease of product isolation, purification and cheapness of the solvent.