Microwave activated synthesis of 2-aryl-quinazolin-4(3H)ones

A highly efficient synthesis of 2-aryl-quinazolin-4（3H）ones was performed by one-pot oxidative heterocyclization of 2- aminobenzamide with aldehydes in the presence of potassium permanganate in dimethylacetamide under microwave irradiation.

Crystal Structure and Physicochemical Properties of a New Tris (2-Amoniumbenzamide) Sulfate (C₇H₉N₂O)₃HSO₄SO₄

Physicochemical properties of a new hybrid compound (C7H9N2O)3HSO4SO4 are synthesized in aqueous solution and characterized by various physicochemical studies. This compound crystallizes in the monoclinic space group P21/c and a unit cell with a = 10.3028(2)A°, b = 12.4995(2)A°, c = 20.6730(2)A°, V = 2600.61(7)A°3, and Z = 8. The structure has been solved using direct method and refined to a reliability R factor of 4.6%. The atomic arrangement of this compound is built up by (HS2O8)3- anionic pairs interconnected with two types (C7H9N2O)22+ cationic pairs via (N, O)-H...O hydrogen bonds. The characterization of these salts was carried out using X-ray diffraction, IR spectroscopy and thermal analysis.

H-Y-zeolites induced heterocyclization:Highly efficient synthesis of substituted-quinazolin-4(3H) ones under microwave irradiation

A highly efficient synthesis of 2-amino-N-substituted-benzamides was performed by the condensation ofisatoic anhydride with several amines in solvent-free conditions under microwave irradiation. H-Y-zeolites induced heterocyclization of these products with ortho-esters under similar conditions afforded the relevant substituted-quinazolin-4（3H）ones in high yields.

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.

Synthesis of 2,3-dihydroquinazolin-4(1H)-ones catalyzed by a-chymotrypsin

We discovered that a-chymotrypsin has a promiscuous ability to catalyze the cyclocondensation of aromatic and aliphatic aldehydes with 2-aminobenzamides to afford the corresponding 2,3-dihydroquinazolin-4（1H）-ones successfully in high yields（90%–98%） under alcohol solvent. The catalytic activity of a-chymotrypsin was evaluated through investigating the temperature, the enzyme loading and the ratio of substrates in the enzyme-catalyzed reactions. The present method proves to be efficient and environmentally friendly in terms of short reaction time, high yield, green catalyst and the clean products obtained without further purification processes.

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.

A Carbon Material as a Strong Protonic Acid for Efficient Synthesis of 4（3H）-Quinazolinones

Carbon-based solid acid catalyst has been applied to catalyzing the synthesis of 4（3H）-quinazolinones from the cyclization reaction of 2-aminobenzamide with aroyl chlorides. The results showed that the catalyst was very efficient with the average yield over 85%. This carbon material with strong protonic acid sites as heterogeneous cata- lyst has some advantages such as high activity, strikingly simple work-up procedure, non-pollution, and reusability, which will contribute to the green process greatly.