Isolation of 2-ethyl-3-methylmaleimide N-β-D-glucopyranoside from Riesling wine

A glycosidic isolate of Riesling urine was separated with multilayer coil countercurrent chromatography (MLCCC). After acetylation and subsequent purification by high performance liquid chromatography (HPLC), the N-beta-D-glucopyranoside of 2-ethyl-3-methylmaleimide (3-ethyl-4-methyl-1 H -pyrrole-2,5-dione) 2 was identified for the first time as natural wine constituent. The identification was carried out by mass spectrometry (EI-MS, DCI-MS) as well as nuclear magnetic resonance spectroscopy (H-1 NMR, 13 C NMR, COSY, HMBC).