Synthesis and characterisation of α-Glycosyloxyamides derived from cyanogenic glycosides.

Sendker J, Nahrstedt A

Abstract

INTRODUCTION After exposure to oxidative stress, the leaves of some cyanogenic plants contain primary α-glycosyloxyamides with structures corresponding to their original cyanogenic glycosides. OBJECTIVES The aim of this study was to prepare such amides from their nitrile precursors and to characterise the new substances in order to facilitate their early identification in forthcoming studies. Methods - A simple but highly specific method is described for the in-vitro synthesis of the amides from their nitrile glycoside precursors using the Radziszewski reaction with hydrogen peroxide and a single-step purification of the reaction product. A TLC method is presented for the preliminary and fast identification of the α-glycosyloxyamides. RESULTS Following this procedure, seven representative α-glycosyloxyamides, five of them new, were obtained and analytically characterised by means of (1) H, (13) C NMR and ATR-IR spectroscopy, highlighting the differences from their respective nitrile glycoside precursors. CONCLUSION Thus, α-glycosyloxyamides can be obtained in sufficient amounts and purity to serve as references for further studies on the catabolism of cyanogenic glycosides and the detoxification of cyanogenic foodplants using the new aspect of nitrile hydrolysis with (endogenous) hydrogen peroxide.