Steric and electronic substituent effects in hydrolysis and aminolysis of 4-alkyl-4-methyl-2-aryl-4,5-dihydro-1,3-oxazol-5-ones

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216275%3A25310%2F05%3A00003027" target="_blank" >RIV/00216275:25310/05:00003027 - isvavai.cz</a>

Result on the web

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DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Steric and electronic substituent effects in hydrolysis and aminolysis of 4-alkyl-4-methyl-2-aryl-4,5-dihydro-1,3-oxazol-5-ones

Original language description

The kinetics and mechanism of the acid-catalysed hydrolysis of substituted 4-alkyl-4-methyl-2-aryt-4,5-dihydro-1, 3-oxazol-5-ones to the corresponding 2-alkyl-2-benzoylaminopropanoic acids were studied. The Taft correlation of rate constants of the acid-catalysed hydrolysis with alkyl substitution at the 4-position of the 1,3-oxazol-5-one ring is non-linear. In the Hammett correlation, the value of rho to decreases with increasing steric demand of the alkyl substituent. With the 4-isopropyl and tert-butyl derivatives, rho = -0.63 and -0.32, respectively. The protonated 4-isopropyl and tert-butyl derivatives undergo nucleophilic attack by water at the carbonyl carbon atom at the 5-position of the 1,3-oxazol-5-one ring to the extents of ca 70% and 60%, respectively. Another reaction path consists in nucleophilic attack by water at the 2-position of the 1,3-oxazol-5-one ring. The reaction kinetics of aminolyses of substituted 4-isopropyl-4-methyl-2-phenyl-1,3-oxazol-5(4H)-ones (1a, 1b, 1f

Czech name

Sterické a elektronické substituční vlivy při hydrolýze a aminolýze 4-alkyl-4-methyl-2-aryl-4,5-dihydro-1,3-oxazol-5-onů

Czech description

Byla studována kinetika a mechanismus kysele katalyzované hydrolýzy substituovaných 4-alkyl-4-methyl-2-aryl-4,5-dihydro-1,3-oxazol-5-onů na odpovídající 2-alkyl-2-benzoylaminopropanové kyseliny. Taftova korelace rychlostních konstant kysele katalyzovanéhydrolýzy v závislosti na alkylsubstituci v poloze 4- 1,3-oxazol-5-onového cyklu je nelineární. U Hammettovy korelace dochází v závislosti na rostoucí sterické náročnosti alkylsubstituentu k snižování hodnoty konstanty. U 4-isopropylderivátů je rho = -0.63 a u t-butylderivátů -0.32. Protonované 4-isopropyl deriváty jsou nukleofilně atakovány vodou na karbonylovém uhlíku v poloze 5- 1,3-oxazol-5-onového cyklu cca z 70% a t-butylderiváty cca z 60%. Druhou reakční cestou je nukleofilní atak vody na iminovýatom uhlíku v poloze 2- 1,3-oxazol-5-onového cyklu. Kinetika aminolýz 4-isopropyl-4-methyl-2-fenyl-1,3-oxazol-5(4H)-onu, 4-isopropyl-2-(4-metoxyfenyl)-4-methyl-1,3-oxazol-5(4H)-onu a 4-isopropyl-4-methyl-2-(4-nitrofenyl)-1,3-oxazol-5(4H)

Type

J_x - Unclassified - Peer-reviewed scientific article (Jimp, Jsc and Jost)

CEP classification

CC - Organic chemistry

OECD FORD branch

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Project

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Continuities

Z - Vyzkumny zamer (s odkazem do CEZ)

Publication year

2005

Confidentiality

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

Name of the periodical

Journal of Physical Organic Chemistry

ISSN

0894-3230

e-ISSN

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Volume of the periodical

18

Issue of the periodical within the volume

8

Country of publishing house

GB - UNITED KINGDOM

Number of pages

8

Pages from-to

743-750

UT code for WoS article

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EID of the result in the Scopus database

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