Chain Mechanism in the Photocleavage of Phenacyl and Pyridacyl Esters in the Presence of Hydrogen Donors

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216224%3A14310%2F06%3A00015580" target="_blank" >RIV/00216224:14310/06:00015580 - 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

Chain Mechanism in the Photocleavage of Phenacyl and Pyridacyl Esters in the Presence of Hydrogen Donors

Original language description

Excited phenacyl and 3-pyridacyl esters of benzoic acid react with an excess of aliphatic alcohols in a chain reaction process, involving hydrogen transfer from the ketyl radical intermediates, leading to benzoic acid in addition to acetophenone and 3-acetylpyridine, respectively, as the by-products. While the maximum quantum yields reached 4 in both cases, the 2- or 4-pyridacyl ester photoreduction proceeded with the efficiency below 100% under the same conditions. The investigation indicates that a radical coupling between ketyl radicals, both formed from the excited ester by hydrogen abstraction from an alcohol, is accompanied by the elimination of benzoic acid from the ester ketyl radical itself. A partitioning between two reactions was found to beremarkably sensitive to the chromophore nature, such as a position of the nitrogen atom in the pyridacyl moiety. The magnitude of a radical chain process is dependent on the efficiency of consecutive steps that produce free radicals capa

Czech name

Řetězový mechanismus fotochemického štěpení fenacyl a pyridacyl esterů

Czech description

Excited phenacyl and 3-pyridacyl esters of benzoic acid react with an excess of aliphatic alcohols in a chain reaction process, involving hydrogen transfer from the ketyl radical intermediates, leading to benzoic acid in addition to acetophenone and 3-acetylpyridine, respectively, as the by-products. While the maximum quantum yields reached 4 in both cases, the 2- or 4-pyridacyl ester photoreduction proceeded with the efficiency below 100% under the same conditions. The investigation indicates that a radical coupling between ketyl radicals, both formed from the excited ester by hydrogen abstraction from an alcohol, is accompanied by the elimination of benzoic acid from the ester ketyl radical itself. A partitioning between two reactions was found to beremarkably sensitive to the chromophore nature, such as a position of the nitrogen atom in the pyridacyl moiety. The magnitude of a radical chain process is dependent on the efficiency of consecutive steps that produce free radicals capa

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

<a href="/en/project/GA203%2F05%2F0641" target="_blank" >GA203/05/0641: Design and applications of photoremovable protecting groups</a><br>

Continuities

Z - Vyzkumny zamer (s odkazem do CEZ)

Publication year

2006

Confidentiality

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

Name of the periodical

Journal of Organic Chemistry

ISSN

0022-3263

e-ISSN

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Volume of the periodical

71

Issue of the periodical within the volume

2

Country of publishing house

US - UNITED STATES

Number of pages

11

Pages from-to

713-723

UT code for WoS article

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EID of the result in the Scopus database

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