Efikasno premeštanje push-pull 5-supstituisanih 4-oksotiazolidina indukovano piridinijum-hidrobromid-perbromidom pod homogenim reakcionim uslovima

Pyridinium hydrobromide perbromide (PHBP) is a highly efficient reagent for the conversion of 5-substituted-2-alkylidene-4-oxothiazolidine derivatives to the corresponding thiazolidines with two fully delocalized exocyclic double bonds at the C(2) and C(5) positions. This conversion as a two-step bromination-rearrangement process occurs in acetonitrile under homogeneous reaction conditions.Piridinijum-hidrobromid-perbromid (PHBP) je veoma efikasan reagens za konverziju 5-supstituisanih-2-alkiliden-4-oksotiazolidinskih derivata u odgovarajuće tiazolidine sa dve potpuno delokalizovane egzociklične dvogube veze u položajima C(2) i C(5). Ova konverzija je dvofazni proces bromovanja i premeštanja koji se odvija u acetonitrilu pod homogenim reakcionim uslovima

Las actitudes de los padres sobre la adaptación de los niños a la institución preescolar

The aim of this research study is to examine parents´ attitudes towards the process of children´s adjustment to a pre-school institution, as well as towards separation difficulties which are encountered when a child starts attending kindergarten. Research results provide answers to whether parents are familiar with the problems manifested in the children´s adjustment process, as well as with the possibilities of successfully overcoming such issues. The research included 763 parents of pre-school children in the territory of Serbia. The differences in parents´ attitudes have been analysed relative to their sex, education and age. In the course of research the authors resorted to a five-point Likert scale composed of 16 items grouped into the following categories: factors which influence the process of adjustment, indicators of a successfully completed adjustment process and methods for overcoming the issues raised in the process of children´s adjustment to a pre-school institution. Parents believe that children´s satisfaction when they attend kindergarten is a more significant indicator of a successfully completed adjustment process relative to the absence of crying and deprecation, as well as that for the purposes of overcoming the difficulties which occur when children start attending a pre-school institution parents most frequently introduce preschool teachers to their child´s habits and traits, and later talk with the child about events in the kindergarten. Research results indicate the presence of statistically significant differences in parents´ attitudes relative to their sex, i.e. they indicate that the adjustment period is more stressful for mothers than for fathers.El objetivo de la investigación es examinar las actitudes de los padres sobre el proceso de adaptación de los niños a la institución preescolar, y también las dificultades de separación que ocurren con el ingreso del niño en jardín de infantes. Los resultados del estudio proponen respuestas a las preguntas si los padres están familiarizados con los problemas que se manifiestan en el proceso de adaptación de los niños a la institución preescolar, y también preguntas sobre las posibilidades de su superación exitosa. El estudio involucró a 763 padres de niños en edad preescolar de Serbia. Se analizan las diferencias en las actitudes de los padres en relación con el género, el nivel de educación y la edad. En la investigación fue utilizada una escala de evaluación de Likert de cinco pasos, compuesta por 16 ítems agrupados en las siguientes categorías: factores que intervienen en el proceso de adaptación, indicadores de una adaptación exitosa y métodos para superar los problemas que surgen en el proceso de adaptación de los niños a la institución preescolar. Los padres lo consideran que la satisfacción de los niños cuando van al jardín de infantes representa un indicador muy importante de la finalización exitosa del proceso de adaptación en relación a la ausencia de llanto y resentimiento, y de que los padres, para superar las dificultades que ocurren cuando niños empiezan a ir en el jardín de infantes, a menudo se reúnen con maestros para familiarizarlos con los costumbres y las características de sus hijos, y luego hablan con sus hijos sobre los acontecimientos en el jardín de infancia. Los resultados del estudio indican que existen unas diferencias estadísticamente significativas en las actitudes de los padres con respecto al género, es decir, el período de adaptación es más estresante para las madres que para los padres

Vodonična veza u push-pull 5-supstituisanim 2-alkiliden-4-oksotiazolidinima: 1H-NMR spektroskopsko proučavanje

Application of dynamic H-1-NMR spectroscopy added to the understanding of the hydrogen bonds existing in the structurally related 5-substituted-2-alklidene-4-oxothiazolidines in polar and apolar solvents. The equilibrated mixtures of these topical push-pull alkenes in CDCl3 consist of the intramolecularly H-bonded (E)-isomer and intermolecularly H-bonded (Z)-isomer in varying proportions which depend on the solvent polarity. For the representative of the series. (Z)-2-(5-ethoxycarbonylmethyl-4-oxothiazolidin-2-ylidene)-1-phenylethanone, a concentration effect on the degree of intermolecular hydrogen bonding in apolar CDCl3 has been studied.Primenom dinamičke 1H-NMR spektroskopije došlo se do boljeg razumevanja o vrsti vodoničnih veza koje postoje u strukturno sličnim 5-supstituisanim 2-alkiliden-4-oksotiazolidinima u polarnim i apolarnim rastvaračima. Uravnotežene smese ovih tipičnih push-pull alkena u CDCl3 sadrže (E)-izomer vezan intramolekulskom vodoničnom vezom kao i intermolekulski vodoničnom vezom vezan (Z)-izomer u različitim odnosima, koji zavise od polarnosti rastvarača. U slučaju tipičnog predstavnika serije (Z)-2-(5-etoksikarbonilmetil-4-oksotiazolidin- 2-iliden)-1-feniletanona uticaj koncentracije na stepen stvaranja intermolekulske vodonične veze u apolarnom CDCl3 je takođe proučavan

Dynamic adsorption characteristics of thin layered activated charcoal materials used in chemical protective overgarments

The efficiency of a thin layered activated charcoal material used in chemical protective overgarments has been evaluated. The study has been conducted with the aim to obtain protective materials with best characteristics considering resistance to benzene effect under dynamic conditions and to create a new filtration protection device. In order to evaluate dynamic adsorption characteristics of thin layered sorption materials, sophisticated dynamic gas chromatography method is used. The curves of benzene penetration are determined for sandwich materials, and sorption layers used in filtrating protective clothing shows that thin layered carbon sorption materials (type M00) have good protective properties as compared to other similar materials. The findings will help to create conditions for developing a functional model for producing a new protective overgarment in the near future

Scalable, Non-denaturing Purification of Phosphoproteins Using Ga³⁺-IMAC: N2A and M1M2 Titin Components as Study case

The purification of phosphorylated proteins in a folded state and in large enough quantity for biochemical or biophysical analysis remains a challenging task. Here, we develop a new implementation of the method of gallium immobilized metal chromatography (Ga3+-IMAC) as to permit the selective enrichment of phosphoproteins in the milligram scale and under native conditions using automated FPLC instrumentation. We apply this method to the purification of the UN2A and M1M2 components of the muscle protein titin upon being monophosphorylated in vitro by cAMP-dependent protein kinase (PKA). We found that UN2A is phosphorylated by PKA at its C-terminus in residue S9578 and M1M2 is phosphorylated in its interdomain linker sequence at position T32607. We demonstrate that the Ga3+-IMAC method is efficient, economical and suitable for implementation in automated purification pipelines for recombinant proteins. The procedure can be applied both to the selective enrichment and to the removal of phosphoproteins from biochemical samples

Regioselective synthesis of new 5-ethoxycarbonylmethyl-4-oxothiazolidin-2-ylidene bromides and rearrangement reaction thereof

(Z)-5-Substituted-2-alkylidene-4-oxothiazolidine derivatives 2a-c were regioselectively brominated to afford the new, synthetically useful vinyl bromides 3a-c, They undergo novel rearrangement reaction to provide 4-oxothiazolidine derivatives 5a-c containing two fully conjugated exocyclic double bonds. Extremely clean and efficient derivatization of 2a-c to 5a-c was also achieved by a one-pot three-step sequence under mild experimental conditions without isolation of vinyl bromides 3a-c

2-Alkylidene-4-oxothiazolidine vinyl bromides: Versatile precursors for C(5) functionalization via pyridine-assisted bromine transfer

A series of structurally diverse vinyl bromides, derived from push-pull 2-alkylidene-4-oxothiazolidines, undergoes pyridine-assisted bromine transfer from the C=C bond to the C(5) position, enabling different C(5) functionalization, The type of the product depends on the C(5) substituent and, in some cases, the transformation is affected by the substituent at the C=C bond

A novel and efficient 4-oxothiazolidine-1,2-dithiole rearrangement induced by Lawesson's reagent

Functionalized 1,2-dithioles have been synthesized by a ring opening-closing process of 5-substituted- and 5-unsubstituted-2-alkylidene-4-oxothiazolidines with Lawesson's reagent. The C-13 NMR data confirmed the meso-ionic structure of these aromatic-type 1,2-dithioles. (C) 2003 Elsevier Ltd. All rights reserved

Stereo- and regiocontrol of electrophile-initiated rearrangement of push-pull 5-substituted 4-oxothiazolidine derivatives

Regioselective a-bromination of (Z)-5-substituted-2-alkylidene-4-oxothiazolidine derivatives affords, under mild experimental conditions, vinyl bromides 3 in good yields. They undergo rearrangement providing a highly efficient route to the stereodefined 4-oxo-thiazolidine derivatives possessing two fully delocalized exocyclic double bonds at C(2) and C(5) positions. A mechanism of this novel rearrangement reaction via base-promoted proton transfer from one carbanionic site to another, followed by the bromination-dehydrobromination sequence, is proposed. (C) 2001 Elsevier Science Ltd. All rights reserved

Nucleophilic functionalization of 2-alkylidene-4-oxothiazolidines at C(5)-position induced by formation of novel pyridinium salt

The synthesis of unsubstituted pyridinium salt containing the 4-oxothiazolidine moiety bonded via C(5) to the N position of the pyridine nucleus is reported. The nucleophilic displacement of pyridine from pyridinium salt by the selected nucleophiles leads to the formation of new 5-substituted 4-oxothiazolidines in good yields