The unusually strong effect of a 4-cyano group upon electronic spectra and dissociation constants of 3-substituted 7-hydroxycoumarins.

OS Wolfbeis, E Koller, P Hoghmuth

文献索引：Wolfbeis, Otto S.; Koller, Ernst; Hochmuth, Petra Bulletin of the Chemical Society of Japan, 1985 , vol. 58, # 2 p. 731 - 734

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被引用次数: 50

摘要

Synthesis, absorption and fluorescence spectra as well as pK a values of 7- hydroxycoumarins with electron-withdrawing substituents in positions 3 are described. Introduction of a 4-cyano group is achieved by oxidative cyanation of coumarins using potassium cyanide and elemental bromine. 7-Hydroxycoumarins without a 4-cyano group are useful indicators for measuring physiological pH values due to their intense ...