Emad M. El-Telbani

Synthesis of 3-((2,4-dichlorophenoxy)methyl)-1,2,4-triazolo(thiadiazoles and thiadiazines) as anti-inflammatory and molluscicidal agents.

A series of fused and non fused 1,2,4-triazoles with (2,4-dichlorophenoxy) moiety are prepared utilizing 3-((2,4-dichlorophenoxy)methyl)-4-amino-4H-1,2,4-triazole-5-thiol (3). The latter on reaction with carboxylic acids, ethylchloroformate, ethylcyanoacetate and sodium nitrite gives five membered fused triazole derivatives 4a-d, 5, 6, 7 and 10, respectively. The six membered heterocycles 11, 12 and 14 are prepared by cyclization of compound 3 with phenacyl bromide, chloroacetic acid and alpha-bromoketone respectively. Most of the newly synthesized compounds were screened for their anti-inflammatory and molluscicidal activities. The compounds 4b, 4d, 11 and 14 showed potent anti-inflammatory activities in dose dependent manner while compounds 3, 4b, 8 and 10 exhibited promising molluscicidal activities.

Synthesis and molluscicidal evaluation of some new pyrazole, isoxazole, pyridine, pyrimidine, 1,4-thiazine and 1,3,4-thiadiazine derivatives incorporating benzofuran moiety.

Chalcone derivative 3 was synthesized via the base catalyzed Claisen-Schmidt condensation and was used as a precursor for synthesizing pyrazoline 11, isoxazoline 12, pyrazoline carbothioamide 13, 5,6-dihydropyrimidine-2-(1H)-thione 14 and aminopyridinecarbonitrile derivative 15. Bromination of 3 afforded the dibromo derivative 4. Monobromo derivative 5 obtained by boiling 4 in dry benzene in the presence of triethylamine. Fused thiadiazines 9a,b and 1,4-thiazine 9c derivatives were synthesized upon treatment of α-bromopropenone derivative 5 with 4-amino-4H-1,2,4-triazole-3-thiol (6) or 1-amino-2-mercapto-5-methylpyrimidin-4(1H)-one (7) or with 2-aminothiophenol (8) in ethanolic potassium hydroxide solution. The newly synthesized compounds were screened for their molluscicidal activities, whereas compounds 3, 4, 9a, 11 and 15 exhibited promising molluscicidal activities. On the other hand compounds 5, 9b, 9c, 12, 13 and 14 showed a moderate effect as compared to the standard molluscicidal agent (Bayluscide).

New Potential Antimalarial Agents: Design, Synthesis and Biological Evaluation of Some Novel Quinoline Derivatives as Antimalarial Agents.

A novel series of dihydropyrimidines (DHPMs) 4a–j; 2-oxopyran-3-carboxylate 7a,b; 1-amino-1,2-dihydropyridine-3-carboxylate 8; and 1,3,4-oxadiazole derivatives 12 with quinolinyl residues have been synthesized in fairly good yields. The structure of the newly synthesized compounds was elucidated on the basis of analytical and spectral analyses. In vitro antimalarial evaluation of the synthesized quinoline derivatives against Plasmodium falciparum revealed them to possess moderate to high antimalarial activities, with IC50 values ranging from 0.014–5.87 μg/mL. Compounds 4b,g,i and 12 showed excellent antimalarial activity against to Plasmodium falciparum compared with the antimalarial agent chloroquine (CQ).

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.

Linearly Fused Furochromones by Intramolecular Enaminone Reactions

A number of new linearly fused furochromones were synthesized. The methodology was performed starting from naturally occurring visnagin and khellin via enaminone formation using N,N-dimethyl formamide dimethylacetal followed by ring closure in acidic medium. Various reactions on the enaminone derivatives are described.

Synthesis of polyfunctional substituted pyrazoles

Synthesis of pyrazoles incorporating substituted derivatives of 2, 4-dichloroacetic acid residues is described. Reactions with different reagents afford fused and polyfunctional substituted pyrazoles.

Synthesis of substituted 7,7-dialkyl-5-chromanones and related compounds, new potassium channel activator

We describe the synthesis of 1-(6-hydroxy-4-methoxy-7,7-dimethyl-6,7-dihydro-5H-furo[3,2-g]chromen-5-yl) pyrrolidin-2-one (7) analogue to Cromakalim. Moreover, the synthesised furochromanone used to synthesise a fused heterocyclic compounds containing thiophene and coumarin rings via Gewald and Wittig reactions; respectively.

Synthesis of Some Chromanone Derivatives and the Use of DNA in Evaluation of their Biological Activity

Abstract 6-Formyl-7-hydroxy-5-methoxy-2-pentamethylenechromanone (2) was prepared from the naturally occurring “Visnagin” and condensed with benzil, o-phenylenediamine and 3,4-diaminobenzophenone to give the corresponding imidazolylchromanone derivatives 3-5. Knoevenagel reaction of compound 2 with different active methylene compounds afforded benzodipyranone derivatives 12a - c which may be considered as analogues to the naturally occurring “Xanthyletin and Graveolone Compounds”. The structural formula of the new compounds were established by using different methods for their preparation in addition to the instrumental analyses. Some compounds in this study were biologically evaluated for their ability to bind to DNA.