Abdel Moneim El Massry

Synthesis of new series of quinoxaline based MAO-inhibitors and docking studies

A series of 2-benzyl-3-(2-arylidenehydrazinyl)quinoxalines 3, 4-benzyl-1-aryl-[1,2,4]triazolo[4,3-a]quinoxalines 4 and phenyl(1-aryl-[1,2,4]triazolo[4,3-a]quinoxalin-4-yl)methanones 5 analogues were synthesized and investigated for their monoamine oxidase (MAO) inhibitory property. The inhibition profile was found to be competitive for compounds 3k, 3m, 5f and 5n with MAO-A selectivity. Observation of the docked positions of these compounds revealed interactions with many residues previously reported to have an effect on the inhibition of the enzyme. The structural features of the new compounds have been determined from the microanalytical, IR, (1)H, (13)C NMR spectral studies and X-ray crystalography.

A versatile synthetic route to chiral quinoxaline derivatives from amino acids precursors

The synthesis ofN-protected L-amino acid (3-benzylquinoxalin-2-yl) hydrazide derivatives is reported here. 3-Benzyl-2-hydrazinoquinoxaline was prepared and then coupled withN-Boc-L-amino acids including; Alanine, Valine, Leucine, Phenylalanine, Tyrosine, Serine and Proline in the presence of HBTU as a coupling reagent to provide the expected product with high yield and purity. The products were deprotected by p-toluenesulphonic acid in acetonitrile and then the tosylate salts were evaluated for antibacterial and antifungal activity.

Synthesis and structure elucidation of novel fused 1,2,4-triazine derivatives as potent inhibitors targeting CYP1A1 activity

Synthesis and structure elucidation of new series of novel fused 1,2,4-triazine derivatives 3a-3f, 4a-4i and 6a-6b and their inhibitory activities are presented. Molecular structures of the synthesized compounds were confirmed by (1)H NMR, (13)C NMR, MS spectra and elemental analyses. X-ray crystallographic analysis was performed on 2-acetyl-8-(N,N-diacetylamino)-6-(4-methoxybenzyl)-3-(4-methoxy-phenyl)-7-oxo-2,3-dihydro-7H-[1,2,4]triazolo[4,3-b][1,2,4]triazine 3d and 2-acetyl-8-(N-acetylamino)-6-benzyl-3-(4-chlorophenyl)-3-methyl-7-oxo-2,3-dihydro-7H-[1,2,4]triazolo[4,3-b][1,2,4]triazine 4e to secure their structures. The inhibitory effect of these compounds toward the CPY1A1 activity was screened to determine their potential as promising anticancer drugs. Our data showed that compounds 4e, 5a, 5b and 6b possess the highest inhibitory effects among all tested compounds. Furthermore, analysis of triazolotriazine derivatives docking showed that these compounds bind only at the interface of substrate recognition site 2 (SRS2) and (SRS6) at the outer surface of the protein. Amino-acids ASN214, SER216 and ILE462 participate in the binding of these compounds through H-bonds.

A regio- and stereo-controlled approach to triazoloquinoxalinyl C-nucleosides

The synthesis of a new series of acyclic triazoloquinoxalinyl C-nucleosides and their transformation to their cyclic analogs are described following protection, activation, and deprotection with subsequent intramolecular nucleophilic substitution protocol. The antibacterial potency of the new compounds was determined using an inhibition zone diameter test. The results show that 3a and 2b exhibit good activity against Escherichiacoli and Candidaalbicans. On the other hand, the cyclic mesylated C-nucleoside 13 showed activity against the Gram-positive bacteria (Staphylococcusaureus) and antifungal activity against C. albicans.

A Novel Reductive Dehalogenation Using Potassium Hydroxide/Polyethylene Clycol(400)/Xylene Mixtures

Abstract Various halogeno-compounds underwent reductive dehalogenation reaction under the action of KOH/Polyethylene glycol (400) in boiling xylene in high yield.

Structure of the reaction products from dehydroascorbic acid analogues, o-phenylenediamine, and arylhydrazines. X-Ray molecular structure of 3-[L-threo-2,3,4-triacetoxy-1-(phenylhydrazono)butyl]quinoxalin-2(1H)-one hemihydrate

Acetylation of the product obtained from successive reaction of dehydro-L-ascorbic acid with o-phenylenediamine and phenylhydrazine gave 3-[L-threo-2,3,4-triacetoxy-1-(phenylhydrazono)butyl]quinoxalin-2(1H)-one (3) rather than the cyclic structure (4) previously assigned for the reaction product. The structure of compound (3) was confirmed based on 1H NMR, 13C NMR, and X-ray analysis. Reinvestigation of the reaction of 5-phenylfuran-2,3,4(5H)-trione (6) with o-phenylenediamine and an arylhydrazine led to the isolation of two components (7) and (10). The former was found to exist in dimethyl sulphoxide solution as a tautomerie mixture of hydrazone imine and diazenyl enamine. Attempted acetylation of compound (7) afforded the furo[2,3-b]quinoxaline ring system (8).