Synthesis, crystal structure, Hirshfeld surface analysis, biological evaluation, DFT calculations, and in silico ADME analysis of 4-arylidene pyrazolone derivatives as promising antibacterial agents
The present paper describes an ultrasound-assisted synthesis of a series of 4-arylidene-1H-pyrazol-5(4H)-one derivatives (3a-i) catalyzed by sulfamic acid. The prepared compounds were characterized by physical and spectroscopic techniques and for compound
New Aspects in the Reaction of Azomethines with Cyclic CH-Acidic Compounds
Treatment of substituted benzylidene anilines 1a - f with cyclic CH-acidic compounds 2a - m in ethanol at room temperature yields in addition/elimination reactions the corresponding arylidene derivatives 4 and the 2:1 adducts 5.The addition products 3, which are formed as intermediates, could not be isolated in any case.The donor/acceptor effect of the substituents on the benzylidene moiety influences to a significant extent the reactivity towards the azomethine carbon. Keywords.Azomethine; CH-Acidic compound; Addition/elimination reaction.
Hennig, Lothar,Alva-Astudillo, Mario,Mann, Gerhard,Kappe, Thomas
p. 571 - 580
(2007/10/02)
Clay Catalysis: Dry Condensation of 3-Methyl-1-phenyl-5-pyrazolone with Aldehydes under Microwave Irradiation
3-Methyl-1-phenyl-5-pyrazolone (1) and arylcarboxyaldehydes (2) were condensated to 1-phenyl-3-methyl-4-(arylmethylene)-5-pyrazolone (3) in presence of acidic clay KSF without solvent under microwave irradiation.
Villemin, Didier,Labiad, Bouchta
p. 3213 - 3218
(2007/10/02)
Synthesis of Benzylidenaminopyrazoles and Bispyrazolopyridines
5-Aminopyrazoles 1a-e react with aromatic aldehydes in boiling ethanol to yield azomethines 2a-n.Bispyrazolopyridines 7a-f are obtained by the reaction of 2a-f with an excess of aminopyrazole at higher temperatures via bisaminopyrazoles 5 and bispyrazolodihydropyridines 6.Structure and configuration of the products are assigned by n.m.r. spectroscopy.Reactions with replacement of the arylidene group on azomethine 2b suggest that the transformation of azomethines to bisaminopyrazoles occurs through a mechanism involving addition of the CH-acidic component, with subsequent elimination of aminopyrazole.
Hennig, L.,Hofmann, J.,Alva-Astudillo, M.,Mann, G.
p. 351 - 358
(2007/10/02)
Spectroscopic Studies on 4-(p-Dimethylamino)benzylidene/phenylimino-3-methyl-1-phenyl-2-pyrazolin-5-ones
Electronic absorption spectra of 4-(p-dimethylamino)benzylidene/phenylimino-3-methyl-1-phenyl-2-pyrazolin-5-ones have been studied in polar and nonpolar solvents.HMO and PPP calculations have been undertaken to investigate the first ?* -- ? transition and the effect of replacement of carbon atom in 4-(p-dimethylamino)benzylidene-3-methyl-1-phenyl-2-pyrazolyn-5-one (I) by nitrogen atom as in 4-(p-dimethylamino)-phenylimino-3-methyl-1-phenyl-2-pyrazolin-5-one (II).The electron densities at various positions for the two compounds have been calculated by the SCF calculations.
Ei-Shahawy, Anwar S.,Girgis, Maher M.,Khalil, Zarief H.
p. 94 - 97
(2007/10/02)
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