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Photocycloaddition Reactions of Pyrazinopsoralen with Simple Olefins
Author(s) -
Han Gyu Seok,
Shim Sang Chul
Publication year - 1998
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1998.tb05168.x
Subject(s) - chemistry , furan , excimer , photochemistry , double bond , singlet state , fluorescence , reaction rate constant , excited state , dimethyl fumarate , medicinal chemistry , kinetics , organic chemistry , physics , psychology , quantum mechanics , psychiatry , multiple sclerosis , nuclear physics
ABSTRACT Direct photolyses of pyrazinopsoralen (PzPs) with excess olefins such as dimethyl fumarate (DMFu), dimethyl maleate (DMMa) and dimethyl ethylidenemalonate (DMEM) gave C 4 ‐photocycloadducts. The photoproducts were determined to be 1:1 C 4 ‐cycloadducts formed through the addition of 4′,5′‐furan double bond of the excited P z P s to the olefins. The fluorescence of P z P s was quenched by olefins with rate constants on the order of 10 9 –10 10 M ‐ 1 /s. The appearance of the long‐lived fluorescence component implies a singlet exciplex mechanism for the photocycloaddition reaction of PzPs with excess olefins.