New Styryl 1,3,4-Oxadiazol-Based Fluorometric "Turn on" pH Sensor.

A new 1,3,4-oxadiazole derivative (MeO-SODA) was synthesized, fully characterized by means of IR, NMR and HRMS data and and additionally, its ability to detect extremely acidic pH values ​​was examined. Firstly, the characteristic behavior of MeO-SODA was examined in ten different solvents, revealing that it underwent non-radiative transitions as the hydrogen bonding capacity of solvent increased. Secondly, the absorption and fluorescence measurements for MeO-SODA were conducted across various pH levels (pH 2, 4, 6, 7, 9, 10, 12), with fluorescence emission observed exclusively at pH 2.

Reactions of 3-(-substituted-phenyl)-5-chloromethyl-1,2,4-oxadiazoles with KCN leading to acetonitriles and alkanes via a non-reductive decyanation pathway.

The present work describes an unfamiliar reaction of 5-(chloromethyl)-3-substituted-phenyl-1,2,4-oxadiazoles with KCN affording trisubstituted 1,2,4-oxadiazol-5-ylacetonitriles and their parent alkanes, namely, 1,2,3-trisubstituted-1,2,4-oxadiazol-5-ylpropanes. To the best of our knowledge, the current synthetic route leading to decyanated products will be the first in terms of a decyanation process which allows the transformation of trisubstituted acetonitriles into alkanes by the incorporation of KCN with the association of in situ-formed HCN and most likely through the extrusion of cyanogen which could not be detected or isolated. In addition, the plausible mechanisms were proposed for both transformations.

Preparation and Characterization of Doripenem-Loaded Microparticles for Pulmonary Delivery.

Pneumonia is a bacterial lower respiratory tract infection that has a high morbidity rate. The gram-negative pathogen is a significant cause of nosocomial infections and ventilator-associated pneumonias and is mainly treated by carbapenems. Doripenem is a carbapenem drug, which has a broad-spectrum antibacterial activity.

Microwave-assisted coupling reaction of N-aryl sydnones with 2-nitromethylenethiazolidine: unexpected formation of (Z)-2-(nitro((E)-p-substitutedphenyldiazenyl)methylene)thiazolidines.

Reaction of N-aryl sydnones with 2-nitromethylenethiazolidine straightforwardly gives rise to the formation of (Z)-2-(nitro((E)-p-substitutedphenyldiazenyl)methylene)thiazolidines in xylene and dimethoxyethane under microwave irradiation. A meaningful and plausible mechanism for this transformation is proposed, which anticipates the extrusion of an aceto-lactone-like moiety before a coupling occurs. The structures of all the new compounds were identified on the basis of the data obtained from the NMR, IR, X-ray diffraction spectra, HRMS measurements, and physical characteristics.

Spectrofluorimetric determination of tobramycin in human serum and pharmaceutical preparations by derivatization with fluorescamine.

A simple, sensitive and selective spectrofluorimetric method has been developed for the determination of tobramycin (TOB) in human serum and pharmaceutical preparations. The method is based on the reaction between the primary amino group of TOB and fluorescamine in borate buffer, pH 8.5, to give a highly fluorescent derivative which is measured at 469 nm after excitation at 388 nm.