Syntheses of Severalβ-l-Rhamnopyranosides

Abstract

To investigate the substrate specificity of fl-L-rhamnosidase, the following fl-Lrhamnopyranosides were synthesized: l-(fl-L-rhamnopyranosyl)-DL-glycerol (1), methyl fl-Lrhamnopyranoside (2), methyl 2-0-(fl-L-rhamnopyranosyl)-fl-D-glucopyranoside (3) and methyl 2-O-(fl-L-rhamnopyranosyl)-a-L-arabinopyranoside (4). The synthesis of 3 was performed using Lquinovose with neighboring group participation, which lead stereoselectively to the fl-Lquinovoside. The 2-0H of the L-quinovo-unit was selectively deblocked, oxidized to the keto group, and then stereoselectively reduced, whereby 3 was produced.

Complete Regioselectivity in Staurosporine Chromophore Formation

“…The combined extracts were washed with H 2 O and brine, dried (MgSO 4 ) and evaporated. Chromatography (MTBE/light petroleum, 1:3) yielded 162 mg 20 (0.4 mmol, 83%) as a colourless solid; 21…”