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Synthesis and Reactivity of Photochromic 2 H ‐Chromenes Based on 3‐Carboxylated Coumarins
Author(s) -
Cerqueira Nuno M. F. S. A.,
Rodrigues Lígia M.,
OliveiraCampos Ana M. F.,
Melo de Carvalho Luís H.,
Coelho Paulo J.,
Dubest Roger,
Aubard Jean,
Samat André,
Guglielmetti Robert
Publication year - 2003
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200390264
Subject(s) - chemistry , photochromism , bathochromic shift , coumarin , photochemistry , reactivity (psychology) , benzopyrans , flash photolysis , organic chemistry , fluorescence , kinetics , pathology , quantum mechanics , reaction rate constant , medicine , physics , alternative medicine
New photochromic 2 H ‐chromenes (=2 H ‐1‐benzopyrans) including a 3‐carboxylated coumarin nucleus were synthesized from hydroxycoumarins, and, in one case, the corresponding trimethoxysilylcarboxamide was prepared. The photochromic behavior was studied under flash‐photolysis conditions. The introduction of electron‐withdrawing substituents in this position of the coumarin nucleus led to a global and significant bathochromic shift in the spectra of the open forms and to an interesting intensification in the colorability.