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Photolyse von Naphth[2,3‐ d ]‐1,2,3‐oxadiazol — Ein Beitrag zum Oxiren‐Problem
Author(s) -
Blocher Achim,
Zeller KlausPeter
Publication year - 1994
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19941270315
Subject(s) - chemistry , cyclohexane , indene , ketene , photodissociation , medicinal chemistry , methanol , hydrogen atom abstraction , photochemistry , solvent , radical , organic chemistry
Photolysis of Naphth[2,3‐ d ]‐1,2,3‐oxadiazole — A Contribution to the Oxirene Problem The photolysis of [9a‐ 13 C]naphth[2,3‐ d ]‐1,2,3‐oxadiazole ([9a‐ 13 C] 14 ) in methanol, water, and cyclohexane is studied. In the protic solvents, the Wolff rearrangement products 2‐(methoxycarbonyl)indene ([ 13 CO] 16 ) and 2‐indenecarboxylic acid ([ 13 CO] 23 ) exclusively labelled at the carbonyl carbon are obtained. Furthermore, the photolysis of [9a‐ 13 C] 14 in methanol yields [2‐ 13 C]‐2‐naphthol ( 19 ) as hydrogen abstraction product. The photolytic decomposition of 14 in cyclohexane affords 2‐(2‐naphthoxycarbonyl)indene ( 25 ) and 1‐cyclohexyl‐2‐(2‐naphthoxycarbonyl)indene ( 26 ). The formation of 25 is explained by nucleophilic addition of 2‐naphthol ( 19 ) to the intermediate ketene 21 . 2‐Naphthol ( 19 ) is generated in situ by hydrogen abstraction from cyclohexane. The cyclohexyl radicals, thereby obtained, convert 25 to 26 . Similar photolysis of [9a‐ 13 C] 14 affords [ 13 CO 13 CO] 25 and [ 13 CO 13 CO] 26 labelled at the carbonyl carbon and C‐2 of the naphthalene ring. Thus, independent of the nature of the solvent (methanol, water, cyclohexane), no labelling distribution is found in the photolysis products of [9a‐ 13 C] 14 . This excludes the participation of naphth‐[2,3‐ b ]oxirene ( 17 ) as reactive intermediate.