A spectroscopic investigation of the phenolcarboxylic acids ofCynara scolymus

Summary Spectroscopic investigations in the UV region of the phenolcarboxylic acids that we have isolated from the leaves ofCynara scolymus have been carried out. It has been found that:1. Free caffeic acid can be distinguished from its esters by the changes in the UV spectra under the influence of sodium ethoxide and sodium acetate.2. An o-dihydroxy grouping in esters can be detected from the bathochromic shift observed with boric acid in the presence of sodium acetate.3. An o-dihydroxy grouping can be detected both in esters and in the free acid under the influence of aluminum chloride.Khimiya Prirodynkh Soedinenii, Vol. 2, No. 5, pp. 303–306, 1966