M.H. Helal
Helwan University
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Featured researches published by M.H. Helal.
Molecules | 2010
Hoda Z. Shams; Rafat M. Mohareb; M.H. Helal; Amira E. Mahmoud
The reaction of 2-amino-3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophene with ethyl cyanoacetate gave 2-cyano-N-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-acetamide. The latter was used to synthesize different heterocyclic derivatives comprising thiophene, thiazole, pyrazole, pyridine, pyrimidine, and coumarin rings. The mechanistic and synthetic pathways depended on regioselective attack and/or cyclization by the cyanoacetamido moiety in the key precursor on various chemical reagents. The competition of the reaction pathways including dipolar cyclization, dinucleophilic-bielectrophilic attack, β-attack, Gewald-type attack, and condensation reactions led to the diversity of the synthesized products. The antitumor activities of the synthesized products were studied and evaluated. Most of the compounds revealed high inhibitory effects when screened in vitro for their antiproliferative activity. Three human cancer cell lines, namely, breast adenocarcinoma (MCF-7), non-small cell lung cancer (NCI-H460) and CNS cancer (SF-268) were used in the screening tests. The simplicity of the synthetic procedures which mainly involved one-pot reactions under mild reaction conditions, the convenience of yield production and the diversity of the reactive sites in the produced systems play a valuable role for further heterocyclic transformations and further biological investigations.
Phosphorus Sulfur and Silicon and The Related Elements | 2007
Hoda Z. Shams; Rafat M. Mohareb; M.H. Helal; Amira E. Mahmoud
Aiming to produce cyclized systems with potential bioactivity, a variety of fused and/or pendant thiophene, pyrazole, imidazole, thiazole, triazole, triazine, and coumarin systems were synthesized based on a cyanoacetic 2-[(benzoylamino)thi- oxomethyl] hydrazide precursor. The structure of the synthesized compounds was established based on elemental analysis and spectral data. The antibacterial and antifungal activities of the compounds are discussed and evaluated.
Molecules | 2011
Hoda Zaki Shams; Rafat M. Mohareb; M.H. Helal; Amira E. Mahmoud
A series of novel polyfunctionalized acyclic and heterocyclic dye precursors and their respective azo (hydrazone) counterpart dyes and dye precursors based on conjugate enaminones and/or enaminonitrile moieties were synthesized. The dyes and their precursors are based on 2-cyano-N-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-acetamide, 2-ethoxycarbonyl-N-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-acetamide or 2-phenylcarbamoyl-N-(3-cyano-4,5,6,7-tetrahydrobenzo[b]thiophen-2-yl)-acetamide systems as precursors. The latter compounds were used to synthesize polyfunctional thiophene-, thiazole-, pyrazole, pyridine-, pyrimidine-, oxazine-, as well as acyclic moieties. The dyes and dye precursors were characterized by elemental analysis and spectral methods. All dyes and their precursors were screened in vitro and evaluated for both their antibacterial and antifungal activities. MIC data of the novel dye systems and their respective precursors showed significant antimicrobial activity against most tested organisms. Some compounds exhibited comparable or even higher efficiency than selected standards. Dyes were applied at 5% depth for disperse dyeing of nylon, acetate and polyester fabrics. Their spectral characteristics and fastness properties were measured and evaluated.
Natural Product Research | 2011
Sherif Ea Badr; Mohamed Shaaban; Yehya M. Elkholy; M.H. Helal; Akila S. Hamza; Mohamed S. Masoud; Mounir M. El Safty
The chemical composition and biological activity of three parts (rind, flesh and seeds) of pumpkin fruits (Cucurbita pepo L.) cultivated in Egypt were studied. Chemical analysis of fibre, protein, β-carotene, carbohydrates, minerals and fatty acids present in the rind, flesh, seeds and defatted seeds meal was conducted. Chemical, GC-MS and biological assays of organic extracts of the main fruit parts, rind and flesh established their unique constituents. Chromatographic purification of the extracts afforded triglyceride fatty acid mixture (1), tetrahydro-thiophene (2), linoleic acid (3), calotropoleanly ester (4), cholesterol (5) and 13(18)-oleanen-3-ol (6). GC-MS analysis of the extracts unpolar fraction revealed the existence of dodecane and tetradecane. Structures of the isolated compounds (1–6) were confirmed by NMR and EI-MS spectrometry. Antimicrobial, antiviral and antitumour activities of the fruit parts were discussed. The promising combined extract of rind and flesh was biologically studied for microbial and cytotoxic activities in comparison with the whole isolated components.
Pigment & Resin Technology | 2004
M.H. Helal
A series of azo dye systems, namely, 5‐arylazo‐pyridin‐2‐one dye systems (5a‐k), was synthesised and characterised. The effects of the structural configuration of the pyridinone dye systems on the shifts of the ultraviolet‐visible absorption maxima were investigated. The structural effects of the polyfunctionally substituted pyridinone dye systems on the intensity of colour and fastness properties of the dyed fabrics were also discussed.
Pigment & Resin Technology | 2001
Galal H. Elgemeie; M.H. Helal; Heba M. El‐Sayed
The synthesis and chemistry of nitrogen heterocyclic azo compounds have been extensively studied. Many derivatives of this type were proved to be excellent dyes. Presents a systematic and comprehensive survey of all recently synthesised nitrogen heterocyclic azo dyes according to dyeing methods.
Pigment & Resin Technology | 2002
Galal H. Elgemeie; M.H. Helal; Emam M. Abbas; Ebtissam A. Abdel Mowla
Several new pyridine‐2(1H)‐thione and thieno[2,3‐b]pyridine derivatives containing an arylazo function were obtained. The application and characteristics for the synthesised dyes are demonstrated.
Pigment & Resin Technology | 2003
Galal H. Elgemeie; M.H. Helal; Kawther A. Ahmed
Several new condensed carbocyclic arylazopyrazolo[1,5‐a]pyrimidine derivatives were obtained from 4‐arylazo‐3,5‐diaminopyrazoles as starting components. The application and dye characteristics for the synthesized dyes are demonstrated.
Pigment & Resin Technology | 2001
Hoda Z. Shams; M.H. Helal; F.A. Mohamed
Three series of azo dye systems are considered, namely, 5‐oxo‐2‐pyrazoline azo dye systems 9 a‐d,1‐oxo‐pyrazolo pyrazole azo dye systems 10 a, b, c, e, 11 a, b, c, e, 12 a, b, c, e, 13 a‐d and 6‐oxo‐pyranopyrzole azo dye systems 14 a‐d. The shifts of ultraviolet‐visible absorption maxima affected by the structural configuration of the pyrazole dye systems are investigated. The structural effects of the polyfunctionally substituted pyrazole dye systems on the intensity of colour and fastness properties of the dyed fabrics are also discussed. The data of these studies are listed. Colour shades of the synthesized dyes on nylon and acetate fabrics are indicated.
Phosphorus Sulfur and Silicon and The Related Elements | 2001
Hoda Z. Shams; M.H. Helal; F.A. Mohamed
Abstract A number of fused pyrazole systems, namely, 1-oxopyrazolo[1,2-a]pyrazoles, 6-oxopyrano[2.3-c]pyrazole and l-oxo-thieno[3′,2′-3,4]pyrazolol [1,2-a] pyrazoles are synthesized via new synthetic routes