On the applicability of CNDO indices for the prediction of chemical reactivity

A series of CNDO/2 molecular orbital properties were evaluated to determine their utility in parameterizing chemical reactivities. Some of these indices were used previously for only Π electron methods and were extended here to include the σ framework. Theoretical rationales were given for this extension to the semi-empirical all valence electron methods. Four systems, the aromatic hydrocarbons, the benzene derivatives, the substituted benzoic acids, and the substituted phenyl amines, were studied to test how well these indices can parameterize chemical reactivities. This study focused on reactions involving both σ and π electrons where the reactive site is not necessarily on the aromatic framework. For the nonplanar and heteropolar systems, these indices performed as well as the Hückel method did for the classical aromatics. These CNDO indices should perform effectively in multivariable regressions to parameterize the reactivities for more complicated problems such as those encountered in quantitative structure activity relationships of drugs. © 1982 Springer-Verlag

Synthesis, characterization and evaluation of the activity of ten mesoionic compounds against microorganisms

Tres mesoiónicos 1,3,4-tiadiazolio-2-tiolato siete cloruros 1,3,4-triazolio-2-tiol se han sintetizado y se ha probado su actividad contra distintos microoganismos. Las estructuras químicas se determinaron por Análisis Elemental, IR, Masa y espectrometría de RMN 1H e 13C. Las pruebas biológicas indican que los compuestos tienen actividad sustancial contra bacterias Gram positivas y alcohol-ácido-resistentes, actividad moderada contra levaduras, escasa actividad contra otros hongos y son inactivos contra las bacterias Gram negativas ensayadas.Three mesoionic 1,3,4-thiadiazoliuin-2-thiolates and seven 1,3,4-triazolium-2-thiol chlorides have been synthesised and tested for activity against a range of microorganisms. The chemical structures were confirmed by Elemental Analysis, IK, Mass, 1H and 13C NMR spectrometry. The biological tests indicate that the compounds have substantial activity against Gram-positive and alcohol-acid-resistant bacteria; moderate activity against yeasts and little activity against other fungi and are inactive against Gram-negative bacteria.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Synthesis, characterization and evaluation of the activity of ten mesoionic compounds against microorganisms

Tres mesoiónicos 1,3,4-tiadiazolio-2-tiolato siete cloruros 1,3,4-triazolio-2-tiol se han sintetizado y se ha probado su actividad contra distintos microoganismos. Las estructuras químicas se determinaron por Análisis Elemental, IR, Masa y espectrometría de RMN 1H e 13C. Las pruebas biológicas indican que los compuestos tienen actividad sustancial contra bacterias Gram positivas y alcohol-ácido-resistentes, actividad moderada contra levaduras, escasa actividad contra otros hongos y son inactivos contra las bacterias Gram negativas ensayadas.Three mesoionic 1,3,4-thiadiazoliuin-2-thiolates and seven 1,3,4-triazolium-2-thiol chlorides have been synthesised and tested for activity against a range of microorganisms. The chemical structures were confirmed by Elemental Analysis, IK, Mass, 1H and 13C NMR spectrometry. The biological tests indicate that the compounds have substantial activity against Gram-positive and alcohol-acid-resistant bacteria; moderate activity against yeasts and little activity against other fungi and are inactive against Gram-negative bacteria.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Synthesis and Characterization of some New Mesoionic 1,3-Thiazolium-5-thiolates via Cyclodehydration and in situ 1,3-Dipolar Cycloaddition/Cycloreversion

The title compounds were synthesized from C-aryl-N-methylglycines by Naroylation followed by a cyclodehydration to form the corresponding 1,3-oxazolium-5-olates. These were not isolated but converted to the title compounds by an in situ 1,3-dipolar cycloaddition/cycloreversion sequence using carbon disulphide. We have studied the cyclodehydration step using acetic anhydride, trifluoroacetic anhydride and 1,3-dicyclohexylcarbodiimide (DCC) at temperatures not exceding 60oC. Trifluroacetic anhydride proved to be the best reagent, giving a better yield and more easily purified products, although yields were also acceptable with the other two reagents

Synthesis and Characterization of some New Mesoionic 1,3-Thiazolium-5-thiolates via Cyclodehydration and in situ 1,3-Dipolar Cycloaddition/Cycloreversion

The title compounds were synthesized from C-aryl-N-methylglycines by Naroylation followed by a cyclodehydration to form the corresponding 1,3-oxazolium-5-olates. These were not isolated but converted to the title compounds by an in situ 1,3-dipolar cycloaddition/cycloreversion sequence using carbon disulphide. We have studied the cyclodehydration step using acetic anhydride, trifluoroacetic anhydride and 1,3-dicyclohexylcarbodiimide (DCC) at temperatures not exceding 60oC. Trifluroacetic anhydride proved to be the best reagent, giving a better yield and more easily purified products, although yields were also acceptable with the other two reagents