Study of 1-deoxy-1-(indol-3-yl)-L-sorbose,1-deoxy-1-(indol-3-yl)-L-tagatose,and their analgos

摘要

Alkaline degradation of the ascorbigen 2-C-[(indol-3-yl)methyl]-alpha-L-xylo-hex-3-ulofuranosono-1,4-lactone (1a) led to a mixture of 1-deoxy-1-(indol-3-yl)-L-sorbose (2a) and 1-deoxy-1-((indol-3-yl)-L-tagatose (3a).The mixture of diastereomeric ketoses underwent acetylation and pyranose ring opening under the action of acetic anhydride in pyridie in the pesence of 4-dimethyllaminopyridine (DMAP) with the formation of a mixture of (E)-2,3,4,5,6-penta-O-acetyl-q-deoxy-1-(indol-3-yl)-L-xylo-hex-1-enitol (4a) and (E)-2,3,4,5,6-penta-O-acetyl-1-deoxy-1-(indol-3-yl)-L-lyxo-hex-1-enitol (5a),which were separated chromatographically.Deacetylation of 4a or 5a afforded cyclised tetrols,tosylation of which in admixture resulted in 1-deoxy-1-(indol-3-yl)-3,5-di-O-tosyl-alpha-L-sorbopyranose (12a) and 1-deoxy-1-(indol-3-yl)-4,5-di-O-tosyl-alpha-L-tagatopyranose (13a).Under alkaline conditions 13a readily formed 2-hydroxy-4-hydroxymethyl-3-(indol-3-yl)-4,5-di-O-tosyl-alpha-L-tagatopyranose (13a).Under alkaline conditions 13a readily formed 2-hydroxymethyl-3-(indol-3-yl) cyclopenten-2-one (15a) in 90% yield.Similar transformations were performed for N-methyl-and N-methoxyindole derivatives.