STUDIES ON REACTIONS RELATING TO CARBOHYDRATES AND POLYSACCHARIDES: XXXII. THE CONSTITUTION OF SEDOSAN (ANHYDRO-SEDOHEPTOSE)

Abstract

Methylation of sedosan (anhydro-sedoheptose) gives a tetramethyl sedosan, which on oxidation by nitric acid, yields an optically inactive trimethoxy glutaric acid. By esterifying the latter, and treating the ester with anhydrous methylamine, an optically inactive methylamide, presumably trimethoxy riboglutaro-dimethylamide is obtained. No trace of the methylamide of inactive dimethoxy succinic acid could be found. It is thus concluded that sedose possesses a 2:6 oxygen ring and that sedosan is an anhydro-sedopyranose.This is confirmed by the isolation of monotrityl sedosan, which shows that sedosan has only one primary alcohol group. Sedosan is therefore 2:7-anhydro-sedopyranose.The epimerisation of trimethyl δ-arabonolactone into trimethyl δ-ribonolactone apparently takes place only with great difficulty.The structure of sedosan is found to be in harmony with its lack of tendency towards polymerization, and this is in accordance with the views of Hibbert on the relation of structure to polymerization.