85969-45-5Relevant academic research and scientific papers
KINETIC STUDIES OF ?-THERMAL CYCLODIMERIZATION OF 1-(3-PYRIDAZINYL)-3-OXOPYRIDINIUM BETAINES
Iskander, Madlene L.,El-Abbady, Samia A.,Shalaby, Alyaa A.,Moustafa, Ahmed H.
, p. 1951 - 1959 (2007/10/02)
The reactivity of the base induced cyclodimerization of 1-(6-arylpyridazin-3-yl)-3-oxidopyridinium chlorides in a pericyclic process have been investigated kinetically at λ 380 nm.The reaction was found to be second order with respect to the liberated betaine and zero order with respect to the base.On the other hand dedimerization (monomer formation) was found to be first order).It was shown that dimerization is favoured at low temperature, whereas dedimerization process is favoured at relatively high temperature (ca. 70 deg C).Solvent effects on the reaction rate have been found to follow the order ethanol > chloroform ca. 1,2-dichloroethane.Complete dissociation was accomplished only in 1,2-dichloroethane at ca 70 deg C.The thermodynamic activation parameters have been calculated by a standard method.Thus, ΔG has been found to be independent on substituents and solvents.The high negative values of ΔS supports the cyclic transition state which is in favour with the concerted mechanism.MO calculations using SCF-PPP approximation method indicated low HOMO-LUMO energy gap of the investigated betaines.
The Synthesis of 1-(3-Pyridazinyl)-3-oxidopyridinium Betaines and their Reactions with 2? 1,3-Dipolarophiles
Moustafa, A. Heshmat,Shalaby, Alyaa A.,Jones, R. Alan
, p. 564 - 575 (2007/10/02)
1-(3-Pyridazinyl)-3-oxidopyridinium betaines react extremely readily as 1,3-dipoles with both ?-electron excessive and deficient alkenes and with conjugated alkenes.No pure quaternisation products were obtained from the reaction of the cycloadducts with methyl iodide and, consequently, their conversion into tropone derivatives was not possible.
