id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-006907-pdvddowh	Baltina, L. A.	Synthesis of amino acid conjugates of glycyrrhizic acid using N-hydroxyphthalimide and N,N'-dicyclohexylcarbodiimide	2016-02-06		.txt	text/plain	1057	60	59	Synthesis of amino acid conjugates of glycyrrhizic acid with the use of N-hydroxyphthalimide, N,N'-dicyclohexylcarbodiimide, and tert-butyl esters of L-amino acids (valine, isoleucine, phenylalanine, and methionine) was performed followed by deprotection with trifluoroacetic acid. The target amino acid conjugates were isolated by column chromatography on silica gel in 40–45% yield. N-Hydroxyphthalimide (HOPt) has been also applied as a nucleophilic reagent at the formation of the amide bond in the carbodiimide mediated synthesis of peptides [14] ; but its use in the synthesis of amino acid conjugates of glycyrrhizic acid has not yet been reported. The goal of the present work was the synthesis of amino acid conjugates of glycyrrhizic acid with the use of HOPt and DCC and tert-butyl esters of L-amino acids for activation of carboxy groups of the glycoside molecule. Free amino acid con-DOI: 10 .1134/S1070363215120129 jugates 4, 6, 8, and 10 were isolated by column chromatography on silica gel in 40-45% yields.	./cache/cord-006907-pdvddowh.txt	./txt/cord-006907-pdvddowh.txt