Carbohydrate-based polyamides are of interest as biomaterials. We have reported' the synthesis of some derivatives of 6-amino-6-deoxy-p-gluconic acid that are precursors for the synthesis of linear polyamides. Attempts to use 2-amino-2deoxy-D-gluconic acid and its 4,60benzylidene derivative in the synthesis of polypeptides were not successful due to interference by the hydroxyl groups2. We now report the preparation of 2-amino-2-deoxy-3,4,5,6-tetra-O-methyl-p-gluconic acid hydrochloride (1) and its transformation into 4-(p-arubino-tetramethoxybutyl)-1,3-oxazolidine-2,Sdione (2), which is an active monomer for polymerisation reactions.
The synthesis of 1 started from 2-acetamido-2-deoxy-p-glucose (3). Methylation of 3 with methyl sulphate-sodium hydroxide in carbon tetrachloride" gave 40% of 4, but the use of methyl iodide-potassium hydroxide in dry N,N-dimethylform-amide4 gave a yield of 65%. Hydrolysis of 4 with hydrochloric acid3 gave the hydrochloride 5, which reacted with di-tert-butyl dicarbonate in chloroform to afford 6 (90%). The phthalimido derivative 8 was also prepared (67.5%) by the reaction of 5 with phthalic anhydride-acetic anhydride' and 10deacetylation of the product 7. Oxidation of 6 with pyridinium chlorochromate gave the lactone 9 (85%). The lactone 10 was also obtained (95.6%) by oxidation of 8 with acetic anhydride-methyl sulphoxide. Opening of the lactone ring in 9 and methylation of HO-5 was effected with methyl iodide-potassium hydroxide-tetrahydrofuran followed by hydrolysis of the N-Boc group with hydrochloric acid to afford 1. Treatment of 10 under similar conditions was unsuccessful.