Effects of Nonionic Micelles on the Rate of Mononuclear Heterocyclic Rearrangement of (Z)-Phenylhydrazones of 5-Substituted 3-Benzoyl-1,2,4-oxadiazoles

Yonemitsu-type condensations catalysed by proline and Eu(OTf)3

“…This failure may be explained by the weak affinity of the active methylene compound for micelles and its consequent reduced enolisation or by the difficulty in solubilising three reagents in the same micellar compartment. 18,19 2.1.2 Metal catalysis. Aer these unsuccessful experiments in aqueous micelles, we turned to an alternative strategy based on metal catalysis.…”

Supramolecular Complex Formation: A Study of the Interactions between β‐Cyclodextrin and Some Different Classes of Organic Compounds by ESI‐MS, Surface Tension Measurements, and UV/Vis and 1H NMR Spectroscopy

“…So far we have measured the rates of decarboxylation [1] of several 5-amino-1,3,4-oxadiazole-and 5-amino-1,3,4-thiadiazole-2-carboxylic acids variously substituted at the exocyclic nitrogen atom, as well as the rates of rearrangement [2] of the (Z)-phenylhydrazones of some 5-substituted 3-benzoyl-1,2,4-oxadiazoles into the corresponding 4-acylamino-2,5-diphenyl-1,2,3-triazoles in the presence of Triton X-100 (a non-ionic surfactant).…”

“…(2) From the data collected from the ESI-MS and CMC techniques and in view of the fact that the recording of UV/ Vis data must be carried out at pH Ͼ 10, we determined the binding constants by the displacement technique only for some C n PNa 2 (n ϭ 8, 12, 14), for C 18 P∆C 9Ϫ10 Na 2 and for the anionic surfactant SDS.…”

“…[29] On addition of different quantities of a second guest the phenolphthalein salt is displaced from the hostϪguest complex and its concentration in water can A graphical procedure [30] was used to determine the 1:1 binding constants (K II ) between surfactants and β-CD by plotting of S t /P against Q [Equation (1)], where P is obtained from Equation (2). The experimental data do not fit for a 2:1 complex formation.…”

A deep insight into the mechanism of the acid‐catalyzed rearrangement of the Z‐phenylhydrazone of 5‐amino‐3‐benzoyl‐1,2,4‐oxadiazole in a non‐polar solvent

“…Among ring‐to‐ring interconversions, the monocyclic rearrangements of heterocycles (MRH, as named by Boulton and Katritzky)40–53 play an important role in the syntheses of heterocycles containing one nitrogen atom together with other heteroatoms such as nitrogen atoms, oxygen, sulphur, and so on. For this reason, our research group has long been involved in the study of synthetic applications of MRH54, 55, 64–67 as well as their mechanisms, either collecting kinetic data54–71 in very different experimental conditions (e.g., in conventional polar or apolar solvents,54–63 in room‐temperature ionic liquids,64–67 and in the presence of micelles68 or of β ‐cyclodextrins)69–71 or by means of ab initio calculations 72, 73. The results collected by our research group has enabled us to define the reaction mechanism of MRH, which clearly appears to be a S N i process, whose course is favored by its intramolecularity and by thermodynamic factors 59–63, 72, 73.…”