Kinetika a mechanismus bazicky katalyzované degradace substituovaných aryl-N-hydroxykarbamátů, jejich N-methyl a N-fenyl analog

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216275%3A25310%2F04%3A00001316" target="_blank" >RIV/00216275:25310/04:00001316 - isvavai.cz</a>

Výsledek na webu

—

DOI - Digital Object Identifier

—

Jazyk výsledku

angličtina

Název v původním jazyce

Kinetics and mechanism of base-catalysed degradations of substituted aryl-N-hydroxycarbamates, their N-methyl and N-phenyl analogues

Popis výsledku v původním jazyce

The kinetics and mechanism of the degradation reactions of substituted phenyl N-hydroxycarbamates and their N-methyl and N-phenyl analogues have been studied at pseudo-first-order reaction conditions in aqueous buffers and sodium hydroxide solutions at 20 XC and 60 XC and at I = 1 molPlV1. The dependence of log kobs on pH for phenyl N-hydroxycarbamates at pH < 9 and pH > 13 is linear with the unit slope; at pH 10-12 log kobs is pH independent. The Bronsted coefficient betalg is about ˇV1 (pH 7-13) and V1.53 (pH > 13) indicating that the degradation reaction of phenyl N-hydroxycarbamates follows an E1cB mechanism giving the corresponding phenol/phenolate and HOVN=C=O. The latter species undergoes further decomposition to give carbonate, nitrogen and ammonia as final products. In contrast to the phenyl N-hydroxycarbamates the N-methyl derivatives at pH 7-9 undergo degradation to the corresponding phenol/phenolate, carbonate and methylamine via a concerted mechanism (?Ňlg is about V0.75).

Název v anglickém jazyce

Kinetics and mechanism of base-catalysed degradations of substituted aryl-N-hydroxycarbamates, their N-methyl and N-phenyl analogues

Popis výsledku anglicky

The kinetics and mechanism of the degradation reactions of substituted phenyl N-hydroxycarbamates and their N-methyl and N-phenyl analogues have been studied at pseudo-first-order reaction conditions in aqueous buffers and sodium hydroxide solutions at 20 XC and 60 XC and at I = 1 molPlV1. The dependence of log kobs on pH for phenyl N-hydroxycarbamates at pH < 9 and pH > 13 is linear with the unit slope; at pH 10-12 log kobs is pH independent. The Bronsted coefficient betalg is about ˇV1 (pH 7-13) and V1.53 (pH > 13) indicating that the degradation reaction of phenyl N-hydroxycarbamates follows an E1cB mechanism giving the corresponding phenol/phenolate and HOVN=C=O. The latter species undergoes further decomposition to give carbonate, nitrogen and ammonia as final products. In contrast to the phenyl N-hydroxycarbamates the N-methyl derivatives at pH 7-9 undergo degradation to the corresponding phenol/phenolate, carbonate and methylamine via a concerted mechanism (?Ňlg is about V0.75).

Druh

J_x - Nezařazeno - Článek v odborném periodiku (Jimp, Jsc a Jost)

CEP obor

CC - Organická chemie

OECD FORD obor

—

Projekt

—

Návaznosti

Z - Vyzkumny zamer (s odkazem do CEZ)

Rok uplatnění

2004

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Organic&Biomolecular Chemistry

ISSN

0793-0283

e-ISSN

—

Svazek periodika

2

Číslo periodika v rámci svazku

4

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

8

Strana od-do

562-569

Kód UT WoS článku

—

EID výsledku v databázi Scopus

—