Syntheses of derivatives of 2,6-diamino-2,3,4,6-tetradeoxy-DL-erythro-hexose (DL-purpurosamine C) and 2,6-diamino-2,3,4,6-tetradeoxy-DL-threo-hexose (epi-DL-purpurosamine C)

Abstract

Addition of nitrosyl chloride to 2-acetoxymethyl-3,4-dihydro-2H-pyran (7) yielded a dimeric adduct (8), which was converted into methyl 6-O-acetyl-3,4-dideoxy-α-DL-glycero-hexopyranosid-2-ulose oxime (9) on treatment with methanol in the presence of pyridine. Catalytic reduction of the oxime (9), followed by acetylation of the resulting amine, gave a separable mixture of methyl 2-acetamido-6-O-acetyl-2,3,4-trideoxy-α-DL-erythro-hexopyranoside (11)(56%) and the corresponding threo-isomer (12)(20%). These compounds were transformed into the methyl glycosides (17) and (22) of DL-purpurosamine C (2,6-diamino-2,3,4,6-tetradeoxy-DL-erythro-hexose) and epi-DL-purpurosamine C (2,6-diamino-2,3,4,6-tetradeoxy-DL-threo-hexose), respectively, on replacement of the 6-acetoxy-group in each by an acetamido-group.