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Authors = Maher A. El-Hashash

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15 pages, 4157 KiB  
Article
Synthesis and Regioselective Reaction of Some Unsymmetrical Heterocyclic Chalcone Derivatives and Spiro Heterocyclic Compounds as Antibacterial Agents
by Maher A. El-Hashash, Sameh A. Rizk and Saad R. Atta-Allah
Molecules 2015, 20(12), 22069-22083; https://doi.org/10.3390/molecules201219827 - 10 Dec 2015
Cited by 41 | Viewed by 9147
Abstract
A number of novel heterocyclic chalcone derivatives can be synthesized by thermal and microwave tools. Treatment of 4-(4-Acetylamino- and/or 4-bromo-phenyl)-4-oxobut-2-enoic acids with hydrogen peroxide in alkaline medium were afforded oxirane derivatives 2. Reaction of the epoxide 2 with 2-amino-5-aryl-1,3,4-thiadiazole derivatives yielded chalcone [...] Read more.
A number of novel heterocyclic chalcone derivatives can be synthesized by thermal and microwave tools. Treatment of 4-(4-Acetylamino- and/or 4-bromo-phenyl)-4-oxobut-2-enoic acids with hydrogen peroxide in alkaline medium were afforded oxirane derivatives 2. Reaction of the epoxide 2 with 2-amino-5-aryl-1,3,4-thiadiazole derivatives yielded chalcone of imidazo[2,1-b]thiadiazole derivative 4 via two thermal routes. In one pot reaction of 4-bromoacetophenone, diethyloxalate, and 2-amino-5-aryl-1,3,4-thiadiazole derivatives in MW irradiation (W 250 and T 150 °C) under eco-friendly conditions afforded an unsuitable yield of the desired chalcone 4d. The chalcone derivatives 4 were used as a key starting material to synthesize some new spiroheterocyclic compounds via Michael and aza-Michael adducts. The chalcone 4f was similar to the aryl-oxo-vinylamide derivatives for the inhibition of tyrosine kinase and cancer cell growth. The electron-withdrawing substituents, such as halogens, and 2-amino-1,3,4-thiadiazole moeity decreasing the electron density, thereby decreasing the energy of HOMO, and the presence of imidazothiadiazole moiety should improve the antibacterial activity. Thus, the newly synthesized compounds were evaluated for their anti-bacterial activity against (ATCC 25923), (ATCC 10987), (ATCC 274,) and (SM514). The structure of the newly synthesized compounds was confirmed by elemental analysis and spectroscopic data. Full article
(This article belongs to the Collection Heterocyclic Compounds)
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20 pages, 654 KiB  
Article
The Uses of 2-Ethoxy-(4H)-3,1-benzoxazin-4-one in the Synthesis of Some Quinazolinone Derivatives of Antimicrobial Activity
by Maher A. El-Hashash, Khalid M. Darwish, Sameh A. Rizk and Fakhry A. El-Bassiouny
Pharmaceuticals 2011, 4(7), 1032-1051; https://doi.org/10.3390/ph4071032 - 14 Jul 2011
Cited by 24 | Viewed by 7372
Abstract
The behavior of 2-ethoxy-(4H)-3,1-benzoxazin-4-one (1) towards nitrogen nucleo-philes, e.g. ethanolamine, aromatic amines (namely: p-toluidine, p-anisidine, p-hydroxyaniline, o-hydroxyaniline, o-bromoaniline, o-phenylenediamine, p-phenylene- diamine, o-tolidinediamine) p-aminobenzoic acid, glucosamine hydrochloride, 2-amino- nicotinic acid, 1-naphthalenesulfonic [...] Read more.
The behavior of 2-ethoxy-(4H)-3,1-benzoxazin-4-one (1) towards nitrogen nucleo-philes, e.g. ethanolamine, aromatic amines (namely: p-toluidine, p-anisidine, p-hydroxyaniline, o-hydroxyaniline, o-bromoaniline, o-phenylenediamine, p-phenylene- diamine, o-tolidinediamine) p-aminobenzoic acid, glucosamine hydrochloride, 2-amino- nicotinic acid, 1-naphthalenesulfonic acid hydrazide, n-decanoic acid hydrazide, benzoic acid hydrazide, semicarbazide, aminoacids (e.g. D,L-alanine, L-asparagine, L-arginine) and derivatives of 2-aminothiodiazole has been investigated. The behavior of the benzoxazinone towards a selected sulfur nucleophile, L-cysteine, has also been discussed. Formation of an amidine salt as a reaction intermediate has been assumed. The effect of solvent in some reactions has been elucidated. The structures of all the novel quinazoline and quinazolinone derivatives, obtained by heterocyclic ring opening and ring closure were inferred by the IR, MS as well as 1H-NMR spectral analysis. Moreover, the antimicrobial potential of some of the new synthesized derivatives has been evaluated. Full article
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