Kamal M. El-Shaieb

Life Span Extension of Caenorhabditis elegans by Novel Pyridoperimidine Derivative

Zwitterions formed from the addition of triphenylphosphine to dialky acetylene-dicarboxylates attack the nucleus of both 1H-perimidine (1) and 1H-benzo[d]imidazole (9) to form novel pyrido[1,2,3-cd]perimidine and imidazo[4,5,1-ij]quinoline derivatives in moderate yields (64–72%). The biological activity of the products has been studied. Compound 3a was found to extend life span of wild type Caenorhabditis elegans under standard laboratory conditions. Both heat stress and induced chemical stress resistance of wild type C. elegans were improved in a reverse dose-dependent manner due to 3a treatment. In addition, treatment of worms with compound 3a significantly attenuated the formation of advanced glycation end products in a reverse dose-dependent manner.

Reaction of Dimethyl Acetylenedicarboxylate With 2-Mercaptoperimidine and 2-Mercaptobenzimidazole

A mixture of equimolar quantities of dimethyl acetylenedicarboxylate ( 2 ) with either 2-mercaptoperimidine ( 1 ) or 2-mercaptobenzimidazole ( 5 ) was heated in absolute benzene in the presence of triphenylphosphine as a catalyst under reflux conditions for 1 h (the reaction was monitored by TLC until the consumption of the starting materials). The solvent was concentrated under vacuum and the residue was subjected to chromatographic plates using toluene-ethylacetate (2:1) as an eluent. The products in each reaction were separated as two migrating zones. Each zone was removed from the plate and recrystallized from the appropriate solvent. The products of the first reaction are 10-methoxy-11-oxo-11H-8-thia-7,11a-diaza-benzo[de]anthracene-9-carboxylic acid methyl ester ( 3 ) and 8-thia-7,10a-diaza-cyclopenta[a]phenalene-9,10-dicarboxylic acid dimethyl ester ( 4 ), while the products of the second reaction are 3-methoxy-4-oxo-4H-1-thia-4a,9-diaza-fluorene-2-carboxylic acid methyl ester ( 10 ) and benzo[4, 5]imidazo[2,1-b]thiazole-2,3-dicarboxylic acid dimethyl ester ( 11 ). The mechanisms of the observed reactions are suggested.

Synthesis of 1,2,4-triazepine and 1,2,5-triazocine derivatives from the reaction of 2-aminobenzohydrazide with π-acceptors

The formation of metal complexes with acid hydrazides plays an important role in the growth of their biological activity. A simple synthetic strategy is described for the synthesis of novel 1,2,4-tri-azepine and 1,2,5-triazocine derivatives via electron donor–acceptor interaction. Thus when 2-aminobenzohydrazide reacted with tetracyanoethylene (TCNE) and 2-dicyanomethylene-indan-1,3-dione (CNIND) afforded 1,2,4-triazepine derivatives. While on reacting 1 with 2,3-dicyano-5,6-dichloro-1,4-benzoquinone (DDQ), 2,3-dichloro-1,4-naphthoquinone (DCHNQ), 1,4-naphthoquinone and/or 2,3,5,6-tetrabromo-1,4-benzoquinone, 1,2,5-triazocine derivatives were formed.

2-Aminothiophenol as building blocks for novel heterocycles

Herein, the chemistry of 2-aminothiophenol has been utilized in the synthesis of several interesting products such as oxidation and reaction with π-deficient compounds. On oxidizing 2-aminothiophenol by sodium hypochlorite furnishes 2-[(2-aminophenyl)-dithio]aniline. Treatment of the obtained product with acetyl chloride affords N-(2-[2-(acetylamino)-phenyl-disulphanyl)-phenyl]acetamide. Reaction of the former acetamide with POCl3 yields 2-methyl-1,3-benzothiazole. Moreover, (3,4,8,9)-dibenzo-2,7-dithia-5,10-diaza4 4 4propellane is formed on reacting the target 2-aminothiophenol with cyclohexane-1,2-dione, whereas its reactions with electron π-acceptors such as 2,3-dichloro-1,4-naphthoquinone (DCHNQ), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), tetra-cyanoethylene (TCNE), and 1-(dicyanomethylen)acenaphthen-2-one yield various heterocycles.

Reaction of N-imidoylthioureas with dimethyl acetylenedicarboxylate : synthesis of new 1,3,5-thiadiazepines

The reaction of N-imidoylthioureas 2a–e with dimethyl acetylenedicarboxylate (DMAD, 1) led unexpectedly to the 1,3,5-thiadiazepines 6a–e. The mechanism of the reaction is discussed.

Facile synthesis of 4-phenyl-6-[(Z)phenylimino]-3,6-dihydro-1,3,5-thiadiazine-2,2-dicarbonitriles

N-Imidoylthioureas 2a–e reacted with 1,1,2,2-tetracyanoethylene (1) to form the thiadiazines 3a–e. In the case of 1e, tricyanovinylation of a phenyl substituent accompanied formation of the thiadiazine ring.

Synthesis of 1,3-thiazolidin-4-ones; reactivity of the thiosemicarbazone function towards dimethyl acetylenedicarboxylate

Aryl thiosemicarbazones react rapidly in a facile procedure with dimethyl acetylene-dicarboxylate to give substituted (ylidene) hydrazono(4-oxothiazolidin-5-ylidene) acetates in high yields. The synthesised compounds were characterised by spectroscopic methods and the structures confirmed by single crystal X-ray crystallography. Several mechanistic options involving nucleophilic interaction are presented.

Synthesis of dibenzo[ b,e ][1,4]diazepine derivatives

The reaction of (Z)-2-amino-N‘-arylbenzamidines with both 2,3-dichloro-5,6-dicyano-1,4-benzoquinone and 2,3,5,6-tetrachloro-1,4-benzoquinone have been studied. The reactions were carried at room temperature overnight in dry ethyl acetate and proceed via a charge transfer complexe to give dibenzo[b,e][1,4]diazepine derivatives in 35–44% yield. Benzodiazepine derivatives have anti-inflammatory, antiviral, antimicrobial, antileukaemic, antiplatelet, anticonvulsant, antianxiety, antidepressive and antitumour activities. The products were fully characterised according to their spectral analyses.

Synthesis of bis-thiazolidin-4-ones from N,N,N″-(1,ω-alkanediyl)bis(N″-organylthiourea) derivatives

Abstract A new series of (2Z,2′E)-dimethyl 2,2′-[(2Z,2′Z)-3,3′-(alkanediyl)bis(4-oxo-2-iminothiozolidin-3-yl-5-ylidene)]acetates has been synthesized by the reaction of N,N″-(1,ω-alkanediyl)bis(N′-organylthiourea) derivatives with dimethyl acetylenedicarboxylate. The structures were established by spectroscopic data, elemental analyses, and single crystal X-ray crystallography. A rationale for the formation of the products is presented.

Synthesis and antibacterial activity of new substituted ethylidenehydrazinylidene-1,3-thiazol-4-ones

A series of substituted ethylidenehydrazinylidene-1,3-thiazol-4-ones and dimethyl 2-{[4-1(-[5-(2-methoxy-2-oxoethylidene)-4-oxo-3-phenyl-1,3-(thiazolidin-2-ylidene]hydrazonylidene}ethyl)phenyl]aminofumarate were synthesised by condensation of substituted ethylidene-N-phenylhydrazinecarbothioamides with dimethyl acetylenedicarboxylate. The synthesised compounds were characterised by spectroscopic methods and confirmed by single crystal X-ray crystallography. Some of the prepared compounds were screened for their in vitro antibacterial activity against different strains of microorganisms, compound 3b exhibited significant antibacterial activity against Pseudomonas aeruginosa compared to ciprofloxacin with MIC value of 1.12 μg mL−1.