Plant Coumarins: XVII. Synthesis and Transformations of 7-Hydroxy-2-oxo-2H-chromene-6-carboxamides

Umbelliferone-6-carbonyl chloride reacted with amines and α-, β-, and ω-amino acid methyl esters to afford the corresponding N-substituted 7-hydroxy-2-oxo-2H-chromene-6-carboxamides. The reaction of umbelliferone-6-carbonyl chloride with glycine gave 2-(7-hydroxy-2-oxo-2H-chromene-6-carboxamido)acetic acid which was converted into acid chloride, and the latter reacted with benzylamines and α-amino acid methyl esters to produce compounds containing a dipeptide fragment.