【摘要】 由二种方法合成了5-脱羟-L-来苏糖。第一法自 D-半乳糖醛酸制成其二缩乙硫醇钠盐,经脱硫成为 L-岩藻糖酸钙,再行 Ruff 降解而得5-脱羟-L-来苏糖;第二法自 L-岩藻糖合成其二缩乙硫醇,经氧化得二种二乙砜异构体（砜甲和砜乙）,二者经 Fischer（H.O.L.）法降解得同一脱羟糖。由第一法所得粗糖浆借其缩乙二硫醇衍生物的制备而纯化。5-脱羟-L-来苏糖是一种粘稠的糖浆[α]_D^（?）2=-21.6°。其苄基苯腙、缩乙二硫醇和二缩苄硫醇三乙酸酯都是很好的晶体,能用以鉴定该糖。根据紫外吸收光谱,高碘酸的消耗,以及对高锰酸钾和吡啶的反应,砜甲似为开链式不饱和的二乙砜,砜乙似属饱和的呋喃型二乙砜。从纸层析的初步结果指出末端脱羟的戊糖或己糖的比移大于相应的母糖。更多还原

【Abstract】 Previous and his coworkers（1944）have reported the preparation of5-deoxy-L-lyxosc.benzylphenylhydrazone from L-faconic amide by means ofWheerman reaction.Now,5-deoxy-L-lyxose itself has been synthesized by twodifferent methods.The first method is based upon Ruff degradation of calciumL-fuconate,which is prepared from D-galactose through conversion into diethylmercaptal of sodium galactttronato followed by demercaptalization.The secondmethod consists of alkaline degradation of L-fucose-l,l-diethylsulfones accordingto H.O.L.Fischer.The crude 5-dooxy-L-lyxoso obtained has been purifiedthrough the preparation of its crystalline ethylenemercaptal(m.p.108—109℃,[α]_D²⁰-26.3°（c,1.94,methanol.）).The analytically pure dooxy-sugar is a sirup of[α]_D⁶²=-21.6°（c,3.33,water）.It can be characterized by its crystalline derivativeslike benzylphenylhydrazone,ethylene mercaptal and dibenzyl mercaptal triace-tate(m.p.77—78℃,[α]_D¹⁸-205.4°（c,2.03,methanol）).On oxidation of L-fucose-diethylmercaptal with hydrogen peroxide in presenceof trace of ammonium molybdate,two isomeric L-fucose-1,1-dicthylsulfones ofthe same empirical formula C₁₀H₂₀O₇S₂ are formed,one of which is an unsatu-rated sulfone（sulfone A）and the other,a saturated isomer（sulfone B）.Sulfone A（m.p.137°）decolorizes permanganate solution,gives red color with pyridine,andshows an absorption maximum of λ_max 261.5 mμ（methanol）,while sulfone B islacking of these properties and forms a diacetate C₁₀H₁₈O₇S₂（COCH₃）2.From thephysical and chemical-properties of these sulfones it seems that sulfone A is mostpr6bably 1,1-diethylsulfonyl-L-lyxo -3,4,5-trihydroxyhex-1-ene（X）,and sulfone B,1,1-diethylsulfonyl-L-talo-2,5-epoxy-3,4-dihydroxyhexane（Ⅺ）.Paper chromatography shows preliminarily that the pentamethylose and thehexamethylose have grater R_f values than their corresponding pentose and hexose.更多还原