Isolierung und Strukturaufklärung von Neapolitanose (O‐β‐D‐Glucopyranosyl‐(1→2)‐O‐[β‐D‐glucopyranosyl‐(1→6)]‐(D‐glucose), einem neuen Trisaccharid aus den Stempeln von Gartenkrokussen (Crocus neapolitanus var.)

Abstract

Isolation and Structure Elucidation of Neapolitanose (O‐β‐D‐Glucopyranosyl‐(1→2)‐O‐[β‐D‐glucopyranosyl‐(1→6)]‐D‐glucose), New Trisaccharide from the Stigmas of Garden Crocusses (Crocus neapolitanus var.)From the stigmas of Crocus neapolitanus var. ‘Blue Bird’ two new crocetin glycosyl esters were isolated. They contained a hitherto unknown trisaccharide. For the structure elucidation a homonuclear 2D‐1H‐NMR‐shift‐correlation experiment was carried out with the peracetate of the isolated trisaccharide. This experiment revealed that the carbohydrate is O‐β‐D‐glucopyranosyl‐(1→2)‐O‐[β‐D‐glucopyranosyl‐(1→6))]‐D‐glucose, for which we suggest the name ‘neapolitanose’. The two new C20‐carotenoids from Crocus neapolitanus are crocetin (β‐gentiobiosyl) (β‐neapolitanosyl) ester (4) and crocetin di(β‐neapolitanosyl) ester (5).