5 5,6-アチリジノ糖および抗生物貭ノジリマイシンの合成
詳細
Some 6-azido-5-tosyloxy-hexofuranoses were treated with lithium aluminum hydride or with sodium borohydride/cobalt(II)tris-(α,α'-dipyridyl)bromide to yield the corresponding 5,6-epimines. Thus, 3-O-benzyl-5,6-dideoxy-5,6-epimino-1,2-O-isopropylidene-β-L-idofuranose (10), -α-D-glucofuranose (16), 5,6-dideoxy-5,6-epimino-1,2-O-isopropylidene-β-L-idofuranose (21), and methyl 2,3-di-O-benzyl-5,6-dideoxy-5,6-epimino-α-L-altrofuranoside (32) were synthesized and characterized as their acetates. It was also found that the hydroxyl function in the 3-position considerably affected formation of aziridine or displacement of 5-O-tosyloxy group. The N-acetates of these 5,6-epimines were unstable to acids and treatment with acetic acid easily afforded 6-acetoxy-5-acetamido-hexofuranoses under an attack of acetate ion in the terminal position. Thus, 17 was converted into 6-O-acetyl-5-acetamido-3-O-benzyl-5-deoxy-1,2-O-isopropylidene-α-D-glucofuranose (39), which gave 5-amino-5-deoxy-1,2-O-isopropylidene-α-D-glucofuranose (40) on debenzylation and hydrolysis. Successive treatment of 40 by N- and O-trifluoroacetylation, followed by de-O-acetonation with acids and removal of the protecting group with bases resulted in its conversion, in a good yield, into Nojirimycin (1), a monosaccharide antibiotic produced by some strains of Streptomyces which is active against Sarcina lutea and Xanthomonas oryzae.
