Abdel Massry

ABSTRACT Reaction of phenylpyruvic acid with semicarbazide afforded 6-benzyl-2H-[1,2,4]triazine-3,5-dione ( 1 ) which upon oxidation with potassium dichromate furnished 6-benzoyl-2H-[1,2,4]triazine-3,5-dione ( 2 ) in good yield. Constructing pyrazolo[3,4-e][1,2,4]triazine system ( 4 ) was achieved by reacting 2 with arylhydrazines in ethanolic solution. However treatment of 2 with the less reactive heteroarylhydrazines gave only the corresponding hydrazones ( 3 ). Attempt for constructing 1,2,4,5,10-pentaaza-dibenzo[a,d]cyclohept-3-one ( 7 ) from 2 was failed and (benzoimidazol-2-yl) [1,2,4] triazine derivative ( 6 ) was the only product. Reaction of 1 with phosphorus pentasulphide afforded compounds 8 and 9 . Compound 8 was transformed to the hydrazino compound 14 , which led to the construction of triazolo[4,3-d] [1,2,4]triazine system. Thus compounds 15 and 16 were obtained by reacting 14 with carbon disulfide or acetic anhydride respectively. Attempt to couple 8 with chloroacetic acid failed, while it's known isomer 10 led to the formation of thiazolo [2,3-c] [1,2,4]triazine derivative ( 13 ). Simple theoretical calculation using AM1 and PM3 semiempirical Hamitonian provided rational ways to correlate the reactivity with structure proposed.

ABSTRACT 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).

ABSTRACT 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).

A series of novel functionalized 1,2,4-triazine derivatives was obtained by the reaction of the precursor 4-amino-6-aryl-3-hydrazinyl-1,2,4-triazin-5(4H)-one 1a-b with a variety of carbon donor agents. The structures of these compounds were established by elemental analysis besides IR, 1H- and 13C-NMR spectroscopic methods. As part of our recent research, a preliminary biological activity evaluation showed that compounds 7b and 12b have strong to moderate inhibition to CYP1A1.

In this investigation, we searched for novel MAO-A inhibitors using a 3-benzylquinoxaline scaffold based on our earlier findings. Series of N'-(3-benzylquinoxalin-2-yl)acetohydrazide, 4a, N'-(3-benzylquinoxalin-2-yl)benzohydrazide derivatives 4b-f, N'-[2-(3-benzyl-2-oxoquinoxalin-1(2H)-yl)acetyl]benzohydrazide derivatives 7a-d, (9H-fluoren-9-yl)methyl 1-[2-(2-(3-benzyl-2-oxoquinoxalin-1(2H)-yl)acetyl)-hydrazinyl]-2-ylcarbamate derivatives 8a-c, 2-(3-benzyl-2-oxoquinoxalin-1(2H)-yl)-N'-benzylidene acetohydrazide derivatives 9a-h, and ethyl 2-(3-benzyl-2-oxoquinoxalin-1(2H)-yl)acetate derivatives 10a-e were synthesized and evaluated in vitro as inhibitors of the two monoamine oxidase isoforms, MAO-A and MAO-B. Most of the compounds showed a selective MAO-A inhibitory activity in the nanomolar or low micromolar range. Compounds 4e and 9g were the most potent derivatives with high MAO-A selectivity and their molecular docking studies were performed in order to rationalize the obtained biological result.

Excess molar volumes and relative permittivities at a frequency of 30 kHz for binary mixtures of oligo(oxyethylene glycol) monodecyl ethers(C10Em) for m = 1–8 were determined in n-heptane, n-decane and n-dodecane at 298.15 K and excess molar volumes in n-dodecane. Using Frohlich equation, the apparent dipole moments μ of C10Em were calculated, and the limiting values μ0 determined by extrapolating to the infinite dilution.

Guanidine functions are important motifs and often are present in natural products as well as in many compounds having therapeutic activity.lq2 Consequently, a number of guany-lating reagents in the literature and/or available commercial sources are kno ~ n . ~ - ~

ABSTRACT Excess molar volumes and relative permittivities at a frequency of 30 kHz of oligo(oxyethylene glycol) monodecyl ethers (C10Em ) for m = 1–8 in n-heptane, n-decane or n-dodecane solutions were determined for the mole fraction range 0 < x < 0.04 at the temperature of 298.15 K. By using Frohlich’s equation the apparent dipole moments, μ, of C10Em were calculated, and the limiting values, μ 0, were determined by extrapolating to infinite dilution. The values of μ 0 increase linearly with increasing number of oxyethylene units (m) of oligo(oxyethylene glycol) monodecyl ethers in the range m = 2–8, while μ 0 of C10E1 is less than its extrapolated value. By comparing the present results with our previous ones measured in n-heptane and decane, a solvent effect on μ 0 was found. The excess partial molar volumes of oligo(oxyethylene glycol) monodecyl ethers at infinite dilution increase with increasing m. Those results are discussed from the viewpoint of the interactions between oligo(oxyethylene glycol) monodecyl ethers and solvent molecules.

Abstract A series of 1-aryl-s-triazolo [4, 3-a] quinoxalin-4-ones, 3, were synthesized via the pyrolysis of the corresponding hydrazones, 6. Thus, the cyclodehydrogenation occurred by refluxing them in an inert solvent (eg ethylene glycol) to give the triazoloquinoxalin-4-ones ...

ABSTRACT The transformation of 2-chloro-3-[5-(acetoxymethyl)-1-phenylpyrazol-3-yl]quinoxaline 3 to 1-aryl-4-[5-(hydroxymethyl-1-phenylpyrazol-3-yl][1,2,4]triazolo[4,3-a] quinoxalines 4a-c has been achieved upon treatment with aroylhydrazines in boiling butanol. Compounds 4a-c were smoothly acetylated by acetic anhydride to give their acetyl derivatives 5a-c in good yield. 4-[5-(Acetoxymethyl)-1-phenylpyrazol-3-yl]1-methyl[ 1,2,4]triazolo[4,3-a]quinoxaline was prepared by ring closure of 2-hydrazine-3-[5-(hydroxymethyl)-1-phenylpyrazol-3-yl]quinoxaline 6 by the action of acetic anhydride. The reaction of 6 with acetylacetone afforded 3-[5-(hydroxymethyl)-1-phenylpyrazol-3-yl]-2-(3,5-dimethylpyrazol-1-yl )quinoxaline 8. In addition, the reaction of 3 with sodium, azide in boiling N,N-dimethylformamide yielded the fused tetrazolo[1,5-a]quinoxaline 9.