MS-MS tandem mass spectrometeric studies of some nitropyridyl substituted phenyl ether derivatives

Nitro substituted pyridyl sulfide and amine derivatives were found to exhibit many fragmentation mechanisms a behaviour which is due to the high reactivity of nitropyridyl, nitro heterocyclic and nitro aromatic compounds. The most common mechanism in nitropyridyl derivatives is the ring closure through expulsion of nitrous acid molecule either by elimination of hydrogen and nitro radicals in two steps or a concerted mechanisms. Moreover, the elimination of nitrous acid molecule may occure via skeletal rearrangement of the molecular ion followed by successive loss of hydride and nitroside radicals to form a cyclic fragment. These mechanisms showed the importance of ortho effect, which favours the elimination of HNO2 molecule from the molecular ion. These mechanisms of ring closure could be confirmed on the basis of studied fragmentation processes by tandem mass spectrometry. It is usually used to propose the fragmentations pathways by following up the mass spectra produced from each individual ion

Kinetics of the reactions of 2,4-dinitrophenyl aryl sulphides sulphoxides and sulphones with hydroxide ion in 80 % [v/v] ethanol-water

The effect of substituent for the reactions of 2,4-dinitrophenyl aryl sulphoxide [la], sulphones [2a-i] and sulphides [3a-h] with hydroxide ion in 80% ethanol-water [v/v] at 25C was investigated. The relative mobility of thioaryl, sulfinylphenyl and sulfonyl aryl leaving groups was also discussed

Kinetics of the reaction of 2,4 dinitrophenyl-4-substituted phenyl sulfones with morpholine in methanol

The present article reports the kinetic data of the reaction of 2, 4-dinitrophenyl-4'-substituted phenyl sulfones [1-6] with morpholine and study the effect of substituents in the aryl sulfonyl moiety at different temperatures in methanol

4-Trifluoromethylbenzyl chloride: preparation kinetics and mechanism of its change into bis [4-trifluoromethylbenzyl] ether in alkaline dioxane-water media

The expected alpha-proton abstraction step from the title compound by alkali in dioxane-water media, due to the electron-withdrawing 4-trifluoromethyl group, does not take place instead an S [N]2 reaction followed by an etherification step occurs. This consecutive reaction was studied kinetically in different dioxane-water media at various temperatures

Mass spectra of substituted phenylthiomethyl, and sulfonylmethylbenzoic acids and their esters

The mass spectra of a group of substituted phenylthiomethyl - and phenylsulfonylme-thylbenzoic acids and their esters, showing some uncommon fragmentation pathways, are discussed. The presence of the substituents -COOH, -COOR, OCH3, -CH3, Br, and/or -NO2 had only minor effects on the mode of fragmeentation