Ekhlass Nassar

A combined experimental and theoretical study of the thermal cycloaddition of aryl azides with activated alkenes.

Reactions were performed from aryl azides on the one hand, and activated alkenes coming from β-dicarbonyl compounds or malonodinitrile on the other hand, either with recourse to conventional heating or to microwave activation, to afford 1-aryl-1H-1,2,3-triazoles. The mechanism and the regioselectivity of the reactions involving β-dicarbonyl compounds have been theoretically studied using DFT methods at the B3LYP/6-31G* level: they are domino processes comprising a tautomeric equilibrium of the β-dicarbonyl compounds with their enol forms, a 1,3-dipolar cycloaddition of the enol forms with the aryl azides (high activation energy), and a dehydration process (lower activation energy). The effect of non-conventional activation methods on the degradation of 1,2,3-triazolines was next studied experimentally. Finally, some of the 1,2,3-triazoles such synthesized were evaluated for their bactericidal and cytotoxic activities.

Direct metallation of thienopyrimidines using a mixed lithium–cadmium base and antitumor activity of functionalized derivatives

A series of thieno[2,3-d]- and thieno[3,2-d]pyrimidines have been easily synthesized using as key step a deproto-cadmiation-trapping sequence. Some of the compounds thus synthesized were screened for anticancer (cytotoxic) activities, and (S)-2-(6-iodo-2-phenylthieno[2,3-d]pyrimidin-4-ylamino)-3-phenylpropanoic acid proved to have a significant activity towards liver, human breast and cervix carcinoma cell lines.

Synthesis and Some Reactions of 1-aryl-4-acetyl-5-methyl-1,2,3-triazole Derivatives with Anticonvulsant Activity

The triazoles 3a-d underwent condensation reactions with 4-(piperidin-1-yl)-benzaldehyde to afford the chalcones 5a-d. Chalcone derivatives 5a-d were reacted with 2,3-diaminomaleonitrile, thiourea and hydrazine hydrate to afford the novel diazepine-dicarbonitrile derivatives 7a-d, the pyrimidine-2-thiol derivatives 9a-d and hydrazino-pyrimidines 10a-d respectively. Structures of the prepared compounds were elucidated by physical and spectral data like FT-IR, (1)H NMR, (13)C NMR, and mass spectroscopy. Some of the synthesized compounds were screened for their anticonvulsant activity and SAR.

Synthesis of ferrocene amides and esters from aminoferrocene and 2-substituted ferrocenecarboxylic acid and properties thereof

Different ferrocenecarboxamides were synthesized from aminoferrocene and various acid coupling partners such as Nα-Boc-L-tryptophan and N-protected sugar amino acids (N-Boc-3-amino-3-deoxy-1,2-O-isopropylidene-α-D-ribofuranoic acid, N-Boc-3-amino-3-deoxy-1,2-O-isopropylidene-α-D-xylofuranoic acid and their corresponding homo- and hetero-dimers). Similarly, reactions between 2-aminoethyl ferrocenecarboxylate and N-protected sugar amino acids afforded compounds with a carboxamide functional group remotely positioned from the ferrocene core. The X-ray diffraction structure of one of them showed the presence of an intermolecular hydrogen bond between the amide functional groups. Carbonylamino (or carbonyloxy) and oxycarbonyl 1,2-disubstituted ferrocenes were prepared either as racemic mixtures or in enantiomerically pure (SP) form. Their electrochemical evaluation revealed distinctive features. Interestingly, the enantiomerically pure ferrocene diester showed a large potential shift (+45 mV) in the presence of L-glutamic acid. Finally, some of the synthesized ferrocenes were evaluated for their antibacterial, antifungal and antiproliferative (MCF-7) activities.

Synthesis and Antiproliferative Activity of 1-(4-(1H-Indol-3-Yl)-6-(4-Methoxyphenyl)Pyrimidin-2-yl)Hydrazine and Its Pyrazolo Pyrimidine Derivatives

The target compounds 1-(4-(1H-indol-3-yl)-6-(4-methoxyphenyl)pyrimidin-2-yl)hydrazine (5) was synthesized by reacting 6-(1H-Indol-3-yl)-4-(4-methoxyphenyl)pyrimidine-2(1H)-thione 4 with hydrazine hydrate. Compound 5 was used as a precursor for the synthesis of new pyrazolo pyrimidine derivatives 6-9. Moreover, the 5-amino-1H-pyrazole-4-carbonitrile derivative 6 was then converted into another set of novel compounds 10-14. On the other hand a series of transformations were carried out using the newly synthesized 1-(4-(1H-indol-3-yl)-6-(4-methoxyphenyl) pyrimidin-2-yl)-1H-pyrazolo[3,4-d]pyrimidin-4(5H)-one (11) to afford the pyrazolo pyrimidine derivatives 15-18. Antiproliferatve activities for some of the newly synthesized compounds were evaluated.

Pyridazine Derivatives and Related Compounds, Part 28. 1 Pyridazinesulfonamides: Synthesis and Antimicrobial Activity

The reaction of 3-chloropyridazine 1 with N –(un)Substituted 4-aminosulfonamides 3 gave the 3-substituted aminopyridazines 4 . Also In addition, pyridazine-3-sulfonamides 7 were prepared from the reaction of pyridazine-3-sulfonylchloride 6 with different amines. All of these derivatives have been characterized by analytical and spectroscopic studies, and also were tested for their in vitro antibacterial and antifungal activity against a variety of microorganisms.

Synthesis and Antimicrobial of Some Novel-5-carbomethoxy-2-pyridone Derivatives Containing Sulfonamide Moiety

Dimethyl 4-(methoxymethylene)-2-pentenedioate 2 was selected as the starting material for the synthesis of some novel 2-pyridones containing sulfonamide moiety, which we expected to have biological activities such as bactericidal and fungicidal or other applications of certain interest.

Synthesis, in Vivo Anti-inflammatory, and in Vitro Antimicrobial Activity of New 5-Benzofuranyl Fused Pyrimidines.

Chalcone (3) has been synthesized as a new chalcone derivative bearing benzofuran moiety at 1 position. Such chalcone was used as a model dielectrophile applied to react with some nucleophiles such as 5-amino pyrazoles, 5-amino-1,2,4-triazole, 2-aminobenzimidazole, and 6-uraciles under Michael reaction conditions and resulted in a new series of fused pyrimidines such as pyrazolo[1,5-a]pyrimidines 7a-e, [1,2,4]-triazolo[1,5-a]pyrimidine 9, pyrimido[1,2-a]benzimidazole 11, and synthesis of pyrido[2,3-d]pyrimidinones 13a and b. The structures of the synthesized target heterocyclic compounds were confirmed by microanalytical and spectral data such as Fourier transform (FT)-IR, (1)H-NMR, and MS spectra. The newly synthesized compounds were evaluated for their anti-inflammatory and antimicrobial activities; most showed significant activities.

A convenient synthesis of 3- and 5-amino-1H-pyrazoles via 3(5)-amino-4-(ethylsulfinyl)-1H-pyrazole desulfinylation

Abstract Syntheses of 5-amino-3-aryl- and 3-amino-5-aryl-1H-pyrazoles from β-bromo-α-(ethylsulfanyl)cinnamonitrile are described. The β-bromo-α-(ethylsulfanyl)cinnamonitriles were oxidized with H2O2 to the corresponding β-bromo-α-(ethylsulfinyl)cinnamonitriles. Subsequent treatment of the resulting sulfoxides with hydrazine hydrate or methylhydrazine followed by hydrochloric acid hydrolysis afforded 5-amino-3-aryl- and 3-amino-5-aryl-1H-pyrazoles, respectively, in good yields.