76196-60-6Relevant academic research and scientific papers
Deactivation behavior and excited-state properties of (coumarin-4- yl)methyl derivatives. 1. Photocleavage of (7-methoxycoumarin-4-yl)methyl- caged acids with fluorescence enhancement
Schade, Bjoern,Hagen, Volker,Schmidt, Reinhard,Herbrich, Ralph,Krause, Eberhard,Eckardt, Torsten,Bendig, Juergen
, p. 9109 - 9117 (1999)
The photochemistry of the (7-methoxycoumarin-4-yl)methyl (MCM) carboxylates 3a-d, the mesylate 4, and the phosphates 5a-e has been examined under near physiological conditions in acetonitrile or methanol/aqueous HEPES buffer solution, respectively. Analysis of photoproducts as well as measurements of photochemical quantum yields, fluorescence quantum yields, and lifetimes for the excited singlet state verified the similar photochemical and photophysical behavior of all the esters studied here. 4- (Hydroxymethyl)-7-methoxycoumarin (2) and the corresponding free acids were obtained as major products upon irradiation. The rates of deactivation of the excited MCM derivatives 3a-5e were found to be dependent on the leaving group ability of the anion concerned as well as on the solvent polarity. The polarity dependence and the exclusive formation of 18O-labeled 2 during irradiation of 5a in 18O-labeled water indicate that photocleavage of the excited singlet state of the MCM caged compounds 3a-5e proceeds via a photo S(N)1 mechanism (solvent-assisted photoheterolysis).
Synthesis and Properties of 4-Diazomethyl-7-methoxycoumarin as a New Fluorescent Labeling Reagent for Alcohols and Carboxylic Acids
Takadate, Akira,Tahara, Tsutomu,Fujino, Hiroyuki,Goya, Shujiro
, p. 4120 - 4125 (2007/10/02)
4-Diazomethyl-7-methoxycoumarin (DMC) was synthesized as a new fluorescent labeling reagent for hydroxyl and carboxyl compounds for use in high-performance liquid chromatography.Treatment of 4-formyl-7-methoxycoumarin with p-toluenesulfonohydrazide gave the tosylhydrazone in 87percent yield, and this was derived to DMC in 78percent yield by treatment with 0.2 N NaOH.DMC was practically nonfluorescent in solution and possessed excellent storage properties.DMC reacted with alcohols in dichloromethane at room temperature in the presence of HBF4 as a catalyst to give the corresponding fluorescent coumarin ethers and also reacted with carboxylic acids in acetonitrile on heating to give the esters.DMC derivatives of cholestanol and cholesterol were satisfactorily separated by high-performance liquid chromatography.The present studies indicate that DMC is a useful fluorescent reagent for the labeling of alcohols and carboxylic acids.Keywords: coumarin diazomethane; coumarin ether fluorescence; fluorescent labeling of alcohols; fluorescent labeling of carboxylic acids; HPLC of alcohols
