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Ground and excited state chemistry of some n-supstituted phthalimides
McCormac, Paul B.
The synthesis and photochemistry of a number of A/-(2-hydroxyethyl) phthalimides have been investigated. Irradiation of A/-(2-hydroxy-2- phenylethyl)phthaiimide results in rapid photofragmentation to form /V-methylphthalimide and benzaldehyde. This process is unusual as it involves intramolecular proton transfer from a hydroxyl group to an excited state phthalimido carbonyl as opposed to the expected y-hydrogen abstraction processes. The mechanism has been investigated in regard to role of hydroxyl group and the nature of the excited state involved. The scope of the fragmentation has been investigated by synthesising and irradiating a series of A/-(2-hydroxyethyl)phthalimides differing in the substituents located at the carbinyl carbon. Mono- and di- substitution led to products of fragmentation whereas the unsubstituted A/-(2-hydroxyethyl)phthalimide affords no photoproducts even after prolonged irradiation. A mechanism involving an excited state intramolecular proton transfer mediated by hydrogen bonding between the hydroxyl group and the phthalimido carbonyl has been proposed. The photochemistry of /V-styrylphthalimide and /V-styryltetrachlorophthalimide has also been investigated. Irradiation of A/-styrylphthalimide in a range of solvents leads only to E-Z isomerisation whereas irradiation of A/-styryitetrachlorophthalimide only gives rise to E-Z isomerisation in hydrocarbon solvents. The reactions of phthaloyl-a-amino acid esters with alkyl magnesium halides has also been investigated. Treatment of phthaloyl a-amino acid methyl esters with Grignard reagents affords only products associated with addition to the phthalimido carbonyl as opposed to expected addition to the ester moiety. The structure and relative stereochemistry of these products has been confirmed by single crystal X-ray diffraction.
Keyword(s): Photochemistry; Chemistry; Phthaiimides; Photofragmentation
Publication Date:
Type: Other
Peer-Reviewed: Unknown
Language(s): English
Contributor(s): Pratt, Albert
Institution: Dublin City University
Citation(s): McCormac, Paul B. (1996) Ground and excited state chemistry of some n-supstituted phthalimides. PhD thesis, Dublin City University.
Publisher(s): Dublin City University. School of Chemical Sciences
File Format(s): application/pdf
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First Indexed: 2013-08-29 05:09:42 Last Updated: 2019-02-09 06:30:53