Synthesis and study of substituted coumarins. A facile preparation of D,L‐o‐tyrosine

Abstract

A general procedure for the preparation of aminocoumarins and aminohydroxycoumarins under mild conditions is described. Amino‐ and acetamidoaminocoumarins were prepared by reduction of the corresponding nitro derivatives with sodium borohydride in the presence of 10% palladium on charcoal. Acid hydrolysis of the acetamidoaminocoumarins with (a) concentrated hydrochloric acid in ethanol, or (b) with 1N hydrochloric acid under reflux, gave diaminocoumarins and aminohydroxycoumarins, respectively. Condensation of the ethyl ester of glycine with salicylaldehyde gave 3‐salicylideneaminocoumarin (XIII), the Schiff base of 3‐aminocoumarin (XII). Acid hydrolysis of XIII under the above mentioned conditions, (a) and (b), gave XII and 3‐hydroxycoumarin (XVI), respectively. Hydrogenation of compound XIII in dioxane or in dimethylformamide with 10% palladium on charcoal gave 3‐salicylaminocoumarin (XVII), while hydrogenation of XII, XIII or XVII in acetic acid with traces of water and palladium black gave the amino acid o‐tyrosine.

Copper(II) complexes of coumarin-derived Schiff bases and their anti-Candida activity

“…Coumarin-derived Schiff bases are well known compounds and several reports have been written about their applications as dye and fluorescent agents [30,31]. Iminocoumarins have also been shown to exhibit anti-inflammatory, antibacterial and antifungal activities [32][33][34][35].…”

Fluorogenic substrates for chymotrypsin with new fluorescent markers

“…Compound 2 was prepared from 3-salicylideneaminocoumarin by treatment with benzylamine or with HC1:EtOH (2:l) (13). Compounds 3, 4, and 5 were prepared by reduction of the corresponding nitrocournarins with NaBH4 in the presence of 10% Pd on charcoal as a catalyst (13).…”

3-Hydroxycoumarin as a new matrix for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of DNA

“…3-HC was synthesized following the literature [16], and structure identification was confirmed by IR and NMR. Its most intense absorption band is at 308 nm with extinction coefficient () of 1.075 ϫ 10 4 L mol Ϫ1 cm…”