Synthesis and molecular recognition studies of crown ethers

This short review summarizes the synthesis and molecular recognition studies of crown ether type macrocycles accomplished at the Institute for Organic Chemistry of Budapest University of Technology and Economics in the last few years. The research work reported here belongs to the areas of proton-ionizable crown ethers and chiral macrocycles. Proton-ionizable crown ethers at higher pHs than their pK_a values are mostly ionized to ligand anions which increase the cation-ligand complex stability with enhancement of selectivity and avoid the need for a counter anion to accompany the cation transport or solvent extraction. The latter factor is not only advantageous from energetical point of view, but is also important when counter anions are not required to be transported. Enantiopure chiral macrocycles have also drawn the attention of many researchers, because owing to their enantioselective complexation they are excellent candidates for effective sensors and selectors of the enantiomers of biologically important chiral compounds such as protonated primary organic amines, amino acids and the derivatives of the latters

Synthesis and enantiomeric recognition studies of a novel 5,5-dioxophenothiazine-1,9 bis(thiourea) containing glucopyranosyl groups

A novel optically active 5,5-dioxophenothiazine-1,9 bis(thiourea) containing glucopyranosyl groups was synthesized and its enantiomeric recognition properties were examined towards the enantiomers of tetrabutylammonium salts of chiral α-hydroxy and N-protected α-amino acids using UV–vis spectroscopy

LA COMUNICAZIONE DELL’INSEGNANTE DURANTE LA LEZIONE D’ITALIANO IN CONTESTO SCOLASTICO UNGHERESE: CARATTERISTICHE COMUNI E STRATEGIE INDIVIDUALI

Nel corso dell’apprendimento di una lingua straniera la comunicazione dell’insegnante risulta di primaria importanza: essa fa parte integrante dell’input linguistico a cui gli studenti sono esposti, anzi costituisce l’unico modello linguistico diretto e vivo durante le lezioni. Nel contesto scolastico fuori del paese target, il fatto che l’insegnante di lingua generalmente non sia nativo complica ulteriormente la situazione costringendolo a operare una serie di scelte riguardanti i vari processi comunicativi con gli studenti. Partendo da questa problematica in questo contributo vorrei presentare un panorama complesso per quanto riguarda la comunicazione del docente non nativo di italiano nel contesto scolastico ungherese e svelare concezioni, riflessioni e decisioni all'origine delle soluzioni individuali che ho avuto la possibilità di osservare. In base alle riprese audio effettuate durante le osservazioni in 8 licei nel quadro di 11 lezioni, e alle 8 interviste strutturate rivolte ai docenti di italiano, esamino il parlato spontaneo istituzionale del docente d’italiano non nativo.   Teacher talk during Italian lessons in Hungarian schools: common characteristics and individual strategies Teacher talk is of primary importance during foreign language learning: it is part of the linguistic input to which learners are exposed, the only directly accessible and live linguistic model in the classroom. In the school context, outside the target country, that the language teacher is usually non-native complicates the situation even more: the teacher is forced to make a lot of choices about the process of communication in the classroom. Starting from this issue, the article presents a complex survey on non-native teacher talk in Hungarian schools and exposes conceptions, reflections and decisions at the origin of individual solutions which I had the chance to see. Based on audio recordings made during teacher observations in 8 high schools (during 11 lessons) and 8 interviews, I examine the spontaneous teacher talk of non-native Italian teachers