Galal A. M. Nawwar

Zur Reaktivität 4,5-ungesättigter 3-Oxoalkannitrile gegenüberMichael-Acceptoren

The 3-oxonitrile1 as well as the 2-benzylidene-3-oxonitrile4 on reaction with benzylidenemalononitrile or malononitrile, respectively, afford 2-amino-4H-pyran derivative3 in high yield. In contrast, reactions of1 and4 with ethyl benzylidenecyanoacetate (6) or ethylcyanoacetate, respectively, predominantly lead to a carbocyclic compound, which is also obtained as main product on attempted condensation of1 with benzaldehyde. Based on spectroscopic data, structure5 is proposed for the novel compound; its formation is interpreted in terms of piperidine-catalysed addition of1 to4 and subsequent intramolecularMichael addition. Reaction mechanisms for the conversion of1 and6 or4 and ethylcyanoacetate to5 are discussed.

Protective Effect of a Synthetic Antioxidant "Acetyl Gallate Derivative" Against Dimethoate Induced DNA Damage and Oxidant/Antioxidant Status in Male Rats

The present study was conducted to investigate the protective effects of a synthetic antioxidant “acetyl gallate derivative” (SAC) against hepatic oxidative stress and brain DNA damage induced by dimethoate (DM) in male rats. DM was orally administrated to the rats at a dose of 38.7 mg kg-1 b.wt. (1/10 LD50), for 28 consecutive days. Additional DM groups received either SAC or vitamin C (VC) at a dose of 200 mg kg-1 b.wt. 30 min before DM administration. Compared to the control, DM induced a statistical reduction in body weight gain, while induced a statistical increase in absolute and relative liver weights. Oral administration of DM significantly caused increases in hepatic lipid peroxidation (LPO) and activities of antioxidant enzymes including catalase (CAT), superoxide dismutase (SOD) and glutathione-s-transferease (GST), while caused decreases in glutathione content (GSH) and serum cholinesterase(ChE) activity. Administration of SAC attenuates LPO, GSH content and antioxidant enzymes system. The severity of brain DNA damage monitored by damage index (DI) and damage frequency % (DF) induced by DM was mitigated after administration of SAC. In conclusion, supplementation of SAC is more reliable than VC in attenuating relative liver weight, SOD, GST, and brain DNA damage.

Simple syntheses of benzothiazol‐2‐ylazoles

Syntheses of the title ring systems are described starting with benzothiazol-2-ylacetohydrazide (1). Thus, 1 was reacted with carbon disulfide to afford the 2-methyl heteroaryl derivative 2, which on reaction with hydrazine hydrate yielded the corresponding triazole compound 3. Also, 1 can undergo a reaction with an isothiocyanate to give the N-thiocarbonyl adduct 4 that can then be cyclized to produce a 2-methyl heteroaryl analog 5 or 6. Compounds 8 or 9 could be obtained by the reaction of 1 with an aryl aldehyde followed by malononitrile or via its self-cyclization, respectively.

Facile synthesis of heterocycles having bacteriocidal activity incorporating oleic acid residues

Synthesis of various heterocycles having fatty acid residues is described using ethyl-4-(hexadec-7-enyl)-3-oxobutanoate as starting material by reaction with different reagents. Preliminary antibacterial testing showed that the compounds ethyl-4-(hexadec-7-enyl)-3-oxobutanoate and 3-[octadec-9-ene-1-one]-chromen-2-one are the most promising.

Cyanoacetylurea in heterocyclic synthesis: A simple synthesis of heterocyclic condensed uracils

The condensation products of cyanoacetylurea with carbonyl compounds were utilized to prepare fused uracils through the intermediate formation of o-aminoureidocarbonyl heterocycles.

Synthesis of some new 1,2,4-triazoles containing olyl moiety and evaluation of their antimicrobial and antioxidant activities

Abstract4-Amino-5-(heptadec-8-en-1-yl)-4H-1,2,4-triazole-3-thiol was prepared for the first time and reacted with different reagents to yield new series of 3-olyl-6-substituted [1,2,4]triazolo[3,4-b]thiadiazoles, 3-olyl-6-substituted [1,2,4]triazolo[3,4-b]thiadiazines, and S- or N-substituted 3-mercapto-1,2,4-triazoles. The synthesized compounds have been evaluated for their antimicrobial and antioxidant activities. These studies revealed that some of the screened compounds have promising antimicrobial and antioxidant activities.Graphical abstract

First novel synthesis of triazole thioglycosides as ribavirin analogues

ABSTRACT This study reports a novel and efficient method for the synthesis of the first reported novel class of triazole thioglycosides. These series of compounds were designed through the reaction of potassium cyanocarbonimidodithioate 2 with hydrazine derivatives 3a-d in EtOH at room temperature to give the corresponding potassium 5-amino-1H-1,2,4-triazole-3-thiolates 4a-d. The latter compounds were treated with tetra-O-acetyl-α-D-glucopyranosyl bromide 6a and tetra-O-acetyl-α-D-galactopyranosyl bromide 6b in DMF at room temperature to give in high yields the corresponding triazole thioglycosides 7a-h. Treatment of triazole salts 4a–d with hydrochloric acid afforded the corresponding 3-mercaptotriazoles 5a-d. Compounds 5a-d were then reacted with bromoperacetylated sugars 6a,b in sodium hydride-DMF at ambient temperature to afford the thioglycosyl compounds 7a-h. Ammonolysis of the triazole thioglycosides 7a-h afforded the corresponding free thioglycosides 8a-h. The scope and limitation of the method is demonstrated. The structure of the reaction products was confirmed on the basis of their elemental analysis and spectral data (IR, 1H NMR, MS and 13C NMR).