The treatment of benzyl 2,3-O-isopropylidene-β-L-xylopyranoside with N-hydroxyphthalimide under Mitsunobu conditions, followed by protecting-group interchange, gave benzyl 4-O-[(tert-butoxycarbonyl)amino]-2,3- O-isopropylidene-α-D-arabinoside. Mild acid hydrolysis and catalytic hydrogenolysis afforded 4-O-[(tert-butoxycarbonyl)amino]-D-arabinose that, upon heating in water, gave the dihydrooxazine [(4R,5S,6R)-5,6-dihydro-4,5-dihydroxy-6-hydroxymethyl-4H-1,2-oxazine] as a crystalline solid. A single-crystal structure determination of this solid showed it to exist in the 5H6 conformation. Reduction of the dihydrooxazine gave the tetrahydrooxazine [(4R,5S,6R)-4,5-dihydroxy-6-hydroxymethyl-3,4,5,6-tetrahydro-2H-1,2-oxazine]. The dihydrooxazine was an effective inhibitor of two β-glucosidases (Ki = 27 and 35 µM). Benzyl 2,3-O-isopropylidene-β-L-xylopyranoside, via the derived imidazylate, was converted into a nitrile that, upon reduction and protecting-group manipulations, gave benzyl 4-C-aminomethyl-4-deoxy-α-D-arabinoside. Treatment of this amine with hydrogen and palladium-on-carbon gave isofagomine.Key words: dihydrooxazine, tetrahydrooxazine, isofagomine, iminosugars, glycosidase inhibitors.
将苯甲基2,3-O-异丙基甲醚-β-L-木糖苷在Mitsunobu条件下与N-羟基邻苯二甲酰亚胺反应,随后进行保护基交换,得到苯甲基4-O-[(叔丁氧羰基)氨基]-2,3-O-异丙基甲醚-α-D-阿拉伯糖苷。经轻酸水解和催化氢解后,得到4-O-[(叔丁氧羰基)氨基]-D-阿拉伯糖,加热水后,得到二氢噁嗪[(4R,5S,6R)-5,6-二氢-4,5-二羟基-6-羟甲基-4H-1,2-噁嗪],为结晶固体。该固体的单晶结构测定显示其存在于5H6构象。对二氢噁嗪进行还原得到四氢噁嗪[(4R,5S,6R)-4,5-二羟基-6-羟甲基-3,4,5,6-四氢-2H-1,2-噁嗪]。二氢噁嗪是两种β-葡萄糖苷酶的有效抑制剂(Ki=27和35 µM)。苯甲基2,3-O-异丙基甲醚-β-L-木糖苷通过衍生的咪唑酸酯转化为一个腈,经还原和保护基操作后,得到苯甲基4-C-氨甲基-4-脱氧-α-D-阿拉伯糖苷。处理这种胺与氢和钯-碳后得到异法戈胺。关键词:二氢噁嗪,四氢噁嗪,异法戈胺,亚胺糖,糖苷酶抑制剂。