Mohammad M. Al-Arab

A unique trimolecular Michael reaction and cyclization

Abstract 1,3-Diaryl-2-propene-1-ones react with ethyl cyanoacetate in presence of sodium ethoxide at room temperature to give 2-aroyl-1,3,5-triaryl-4-carbethoxy-4-cyanocyclohexanols. The structure of the reaction products was established by infrared, H-1 and C-13 nuclear magnetic resonance spectral data as well as elemental analysis. X-ray crystallography shows the presence of the cyclohexanol moeity.

A new convenient synthetic method for 3,4-diaryl-2,6-piperidinediones

A one-pot reaction for the preparation of 3,4-diaryl-2,6-piperidinediones through acid hydrolysis of the corresponding ethyl 3,4-diaryl-4-cyanobutyrates is described.ZusammenfassungDurch saure Hydrolyse der entsprechenden Ethyl-3,4-diaryl-4-cyanobutyrate wurden in einem Schritt (Eintopfreaktion) die 3,4-Diaryl-2,6-piperidindione dargestellt.

Synthesis, identification and preliminary evaluation of esters and amide derivatives of diflunisal

Abstract This work examines the suitability of the methyl, ethyl esters and amide derivatives of diflunisal for use as prodrugs to diflunisal. Synthesis, identification and characterization of these forms is described. In vitro hydrolysis studies of these compounds in acidic and alkaline conditions were performed. The compounds were very stable in 0.1 HCl but hydrolyzed to diflunisal at pH 10 following a pseudo-first-order kinetics. The rate of hydrolysis was in the order: methyl ester > amide > ethyl ester, and the rate constants (Kobs) and the half-life of each prodrug was determined. Preliminary in vivo work in rabbits on the methyl ester derivative showed that diflunisal was detected in the blood after 3 h of administration and suggesting that the methyl ester was converted in vivo to the parent drug diflunisal. The very poor water solubility of these derivatives and the very low rate of hydrolysis in 0.1 N HCl may overcome both the bitter taste of the drug and its gastric irritant action, respectively.

Synthesis of 2,5‐diaryl‐2,4‐pentadienenitriles and their spectral, fluorescence and mutagenic properties

The condensation of substituted cinnamaldehydes and arylacetonitriles using sodium ethoxide in ethanol at room temperature afforded 2,5‐diaryl‐2,4‐pentadienenitriles in good yield. The structure of the reaction products was established on the basis of their infrared, nuclear magnetic resonance and elemental analysis data. Two representative compounds were studied for their mutagenic activity. One of them showed a weak mutagenicity while the second showed a high mutagenic activity in TA97a Salmonella strain. Both were negative in TA100. Some of these pentadienenitriles showed fluorescence in solutions.

Mutagenic activity of three pentadienenitrile derivatives of suspected herbicidal action

The mutagenic activity of three pentadienenitrile derivatives was investigated. The compounds are: 2‐(p‐fluorophenyl)‐5‐phenyl‐2,4‐pentadienenitrile. 2‐(p‐chorophenyl)‐5‐phenyl‐2,4‐pentadienenitrile and 2‐(p‐bromophenyl)‐5‐(o‐nitrophenyl)‐2,4‐pentadienenitrile. These compounds are newly synthesized and are of suspected herbicidal activity. Using Ames test the results showed that two of these compounds (a and c) can induce both frameshift and base pair substitution mutations. The third compound induced only base pair substitution. However, the mutagenic activity of these compounds is not very strong. Therefore, we suggest further investigation using different test systems, prior to any decision concerning their use as herbicides.

Synthesis, spectroscopy and mutagenicity of novel heptenedinitriles

In this paper we report the isolation of an unexpected product from the condensation of α‐methylcinnamaldehyde with arylacetonitriles using sodium ethoxide at room temperature, 2,6‐Diaryl‐4‐methyl‐5‐phenyl‐2‐heptenedinitriles were obtained as a result of a 1,4 and 1,2‐addition of the arylacetonitriles enolate at the carbon‐carbon double bond and the carbonyl group of the α,β‐Michael acceptors. The reaction products were identified on the basis of their infrared, proton and carbon‐13 nuclear magnetic resonance spectral data as well as their elemental analyses. Three representative compounds were investigated concerning their mutagenic activity. Two of these compounds showed a weak mutagenicity while the third one showed a relatively stronger mutagenic action using Salmonella typhimurium strains TA97a and TA100.

Anodic oxidation potentials of aromatic cyanoesters

Using cyclic voltammetry, the anodic oxidation potentials for a series of 15 substituted aromatic cyanoesters have been measured and analyzed. Irreversible anodic oxidations were observed, in addition to a cathodic reduction wave. The different aromatic species exhibited different potential values, in accordance with the type of the substituent and nature of the aromatic nucleus.ZusammenfassungUnter Verwendung von cyclischer Voltametrie wurden die anodischen Oxidationspotentiale einer Serie von 15 substituierten aromatischen Cyanoestern gemessen und analysiert. Zusätzlich zu einer kathodischen Reduktionswelle wurden irreversible anodische Oxidationen beobachtet. Dabei zeigten die verschiedenen Verbindungen je nach dem Substitutionstyp und der Natur des aromatischen Kerns unterschiedliche Potentialwerte.