An efficient and improved procedure for the synthesis of 1,4-diazepine and 1,5-benzodiazepine derivatives via the reaction of ketimine intermediates with aldehydes in the presence of Keggin-type heteropolyacids (HPAs) was developed. High yields and short reaction times were obtained for both electron-releasing and electron-withdrawing substituted 1,4-diazepine and 1,5-benzodiazepines derivatives.
The theoretical investigation of the physico-chemical properties of pyrazolooxazine derivatives, which could exhibit anti-inflammatory activity, has been carried out using DFT computations at the B3LYP/6-311[Formula: see text]G (d, p) level. It appears that both pyrazolooxazin-2-one (1) and pyrazolooxazin-2-thione (2) exhibit thermal stability whereas the electron donating character of the latter is higher than that of the former species. Molecular electrostatic potential surfaces (MESP) have been used in order to determine the activity sites of these species. The HSAB (Hard and Soft Acids and Bases) principle helped to determine the reactivity as well as the effect of substituting groups on the molecules. The stability of these compounds has been analyzed using natural bond orbital analyses NBO. Then, the structure-activity properties of a large series of derivatives were investigated using the HyperChem 8.0.6 software considering the Lipinski’s “rule of five”. The results of QSAR analyses showed that the most promising compound among others, named f1 (a thiophen ring being attached to the nitrogen atom 3 of 1) should be a good candidate for experimental testing.
The synthesis of 2,3,4,5,10,11-hexahydro-1H-dibenzo[b,e][1,4]diazepin-1-ones was revisited and a catalyst-free method was established, by exploring the reactivity of 3-[(2-aminoaryl)amino]dimedones towards carbonylated electrophiles. 2D NMR and single-crystal X-ray diffraction studies were used to characterize the structures unequivocally and to review the mechanism leading to the formation of supposed positional isomers. The action of 3-[(2-aminoaryl)amino]dimedones on chromene-3-carboxylic acid, fumaryl, and oxalyl chloride has led to dibenzo[b,e][1,4]diazepin-1-one ring opening to produce novel Z-configured enaminone and linear diamides.
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