Ahmed El-Mekabaty

Chemistry of Enaminonitriles of Pyrano[2,3-c]pyrazole and Related Compounds

Abstract This review highlights the methods used for the synthesis of enaminonitriles of pyrano[2,3-c]pyrazole compounds. Their reactivity and synthetic importance were investigated. In this context, recent progress in the synthesis and use of enaminonitriles of pyrano[2,3-c]pyrazole as precursors for heterocyclic compounds is reviewed. The synthetic routes for preparation of enaminonitriles are based on multicomponent reactions including three- or four-component reactions. Enaminonitriles can be used as building blocks for carbocyclic five-, six-, and seven-membered heterocycles as well as fused heterocyclic compounds. The bibliography includes 94 references. GRAPHICAL ABSTRACT

Novel quinazolinone derivatives: synthesis and antimicrobial activity

Abstract4-(4-Oxo-4H-3,1-benzoxazin-2-yl)phenyl-4-methylbenzenesulfonate (2) was prepared and reacted with some primary aromatic amines, e.g., aniline, p-chloro aniline, p-methoxy aniline, p-amino benzoic acid and p-amino acetophenone. It reacted also with some heterocyclic amines, e.g., 2-aminothiazole, 2-aminobenzothiazole, 5-amino-4-phenylazo-2,4-dihydropyrazol-3-one and 3-amino-2-methylquinazolinone and with diamines; e.g., o-phenylenediamine, p-phenylenediamine, ethylenediamine, semicarbazide hydrochloride and thiosemicarbazide under different conditions. On the other hand, compound (2) reacted with both sodium azide and active methylene compounds, e.g., ethylcyanoacetate and ethylacetoacetate to give (19) and (20), respectively. All new prepared compounds were subjected to antimicrobial activity evaluation.

Chemistry of 2-Amino-3-carbethoxythiophene and Related Compounds

Abstract This review describes the synthesis and reactions of 2-amino-3-carbethoxythiophenes as building blocks for the syntheses of poly functionalized heterocyclic compounds. GRAPHICAL ABSTRACT

Chemistry of 3-(1H-Indol-3-yl)-3-oxopropanenitrile

Abstract This review highlighted the methods used for the synthesis of different heterocyclic compounds derived from 3-(1H-indol-3-yl)-3-oxopropanenitrile. The reactivity and their synthetic importance were investigated. In this context, recent progress in the synthesis and use of 3-(1H-indol-3-yl)-3-oxopropanenitrile as precursors for heterocyclic compounds is reviewed. GRAPHICAL ABSTRACT

Eco-friendly synthesis of amidochloroalkylnaphthols and its related oxazepinones with biological evaluation

A general mild and efficient protocol for the synthesis of amidochloroalkylnaphthol libraries was achieved utilizing SiO2–ZnCl2 (silzic) as a reusable heterogeneous catalyst via Ritter-type reaction, through one-pot, three-component condensation of various aldehydes, chloroacetonitrile, and β-naphthol under solvent-free reaction conditions. The amidochloroalkylnaphthols were cyclized to its related oxazepinones, and their anticancer and antioxidant activities were studied.Graphical Abstract

Synthesis and Antioxidant Activity of Some New Heterocycles Incorporating the Pyrazolo-[3,4-D]Pyrimidin-4-One Moiety

2-(4-Oxo-1-phenyl-4,5-dihydro-1H-pyrazolo[3,4-d]pyrimidin-6-yl)acetonitrile was used as the key intermediate for the synthesis of polyfunctionally substituted heterocycles (e.g., pyrazoles, pyridine, tetrazole, thiazoles, thiophenes, and chromene) incorporating the pyrazolo[3,4-d]pyrimidin-4-one moiety. Representative compounds of the synthesized series were tested and evaluated as antioxidants. Two of the tested compounds (pyrazole and thiophene derivatives) showed antioxidant activity nearly equal to that of ascorbic acid.

Advances in 1,3,5-triazepines chemistry

This review describes a literature survey of 1,3,5-triazepines. The investigated heterocycles were the monocyclic and fused 1,3,5-triazepines. The different sections of the paper cover: theoretical methods, spectroscopy aspects, thermodynamic aspects, synthesis and reactions of the monocyclic and fused heterocycles incorporated into the 1,3,5-triazepine moiety. The biological evaluation of the target compounds are also described as well as their synthetic applications. The reaction mechanisms are discussed.

Utility of 5-Amino-1-phenyl-1H-pyrazole-4-carboxamide in Heterocyclic Synthesis

Abstract This review presents a systematic and comprehensive survey of the methods of preparation and the chemical reactivity of 5-amino-1-phenyl-1H-pyrazole-4-carboxamide as building block for the synthesis of polyfunctionalized heterocyclic compounds with pharmacological interest. GRAPHICAL ABSTRACT

Synthesis and evaluation of some new oxazolones and imidazolones as antioxidant additives for Egyptian lubricating oils

Oxazolone derivative 2 was utilized as a key intermediate for synthesis of some new oxazolone and imidazolone derivatives. Reaction of oxazolone derivative 2 with diamines under different conditions afforded the corresponding imidazolone derivatives 3–8, respectively. Moreover, oxazolone 2 reacted with some heterocyclic amines in glacial acetic acid giving the corresponding imidazolone derivatives 9–14, respectively. Cyclocondensation of thiosemicarbazide with compound 2 in dry pyridine afforded compound 15. Addition of secondary amines to olefin double bond of compound 2 gave the corresponding addition products 16–19, respectively. Michael addition of compound 2 with some active methylene compounds afforded oxazolone derivatives 20–23, respectively. These prepared products were evaluated as antioxidant and corrosion inhibitors for gasoline lubricating oil and compounds 6a–c, 10 and 15 exhibited the highest antioxidant and anticorrosive activities. The effect of concentration of additives was studied to recommend the optimum concentration to be used. The results showed, for additive 15, 0.1 g for 1 L oil was the more effective concentration. Measurements for thermal analysis and of surface tension of oil after oxidation were also carried out.

Chemistry of 3-(2-Haloacyl)indoles

Abstract This review presents a systematic and comprehensive survey of the methods ofpreparation and the chemical reactivity of 3-(2-haloacyl)indoles. These compounds are important intermediates for the synthesis of a variety of otherwise difficult to obtain synthetically useful and novel heterocyclic systems. The data published over the past few years are reviewed here for the first time. GRAPHICAL ABSTRACT