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Small and Medium Rings, 76. Photorearrangement of Polycyclic Quinoxalines, Isomerisations of Isodrin‐Type and Aza‐Di‐π‐Methane Chromophores
Author(s) -
Behr Jürgen,
Braun Ralf,
Martin HansDieter,
Steigel Alois,
Rubin Mordecai B.
Publication year - 1991
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.19911240422
Subject(s) - quinoxaline , chemistry , chromophore , photochemistry , bicyclic molecule , medicinal chemistry , organic chemistry
Abstract The multichromophoric polycyclic quinoxaline 11 has been synthesized starting with diketone 7 . Irrespective of whether quinoxaline 11 is irradiated in its nπ ☆ or ππ ☆ band, the photoproduct formed in high yield is invariably the cage compound 14 . This excitation energy transfer from the quinoxaline to the isodrin subchromophore of 11 is facilitated by a strong mixing of energy levels in these two fragments of 11 , as evidenced by the PE spectrum of quinoxaline 13 . The direct interaction of a quinoxaline chromophore with a nonconjugated double bond, i.e. an aza‐di‐π‐methane rearrangement, is shown to occur photochemically in bicyclic quinoxaline 12 .