Treatment of 2′,3′-O-isopropylideneuridine-5′-aldehyde with the stabilized Wittig reagent, (p-toluenesulfonylmethylene)triphenylphosphorane, gave high yields of 1-[5,6-dideoxy-2,3-O-isopropylidene-6-(p-toluenesulfonyl)-β-D-ribo-hex-5(E)-enofuranosyl]uracil (2). This vinylsulfone (2) underwent isomerization readily in base to give the allylic sulfone, 1-[5,6-dideoxy-2,3-O-isopropylidene-6-(p-toluenesulfonyl)-β-D-erythro-hex-4(Z)-enofuranosyl]uracil (3). Treatment of 2 or 3 with aqueous trifluoroacetic acid gave the corresponding deprotected vinyl (5) or allylic (6) sulfones, and 5 was converted to 6 readily in basic solutions. Treatment of 2 with sodium borohydride, sodium thiomethoxide, or ammonia resulted in conjugate addition (at C5′ of the vinyl sulfone) to give the 5′-hydro, 5′-methylthio, or 5′-amino-5′,6′-dideoxy-6′-(p-toluenesulfonyl) nucleosides. The 5′-substituted diastereomers were deprotected, separated, and the configuration of a 5′-amino derivative was established by X-ray crystallography.Key words: allylic sulfones, amino-nucleosides, 5′,6′-dideoxynucleosides, nucleosides, uridine, vinyl sulfones.
2′,3′-O-异丙基脲苷-5′-醛经稳定的Wittig试剂(p-甲苯磺酰亚甲基)三苯基膦处理,得到高产率的1-[5,6-二去氧-2,3-O-异丙基-6-(p-甲苯磺酰)-β-D-核糖-5(E)-烯基呋喃核糖核苷]嘧啶(2)。该乙烯基砜(2)在碱性条件下容易发生异构化,形成烯基砜,1-[5,6-二去氧-2,3-O-异丙基-6-(p-甲苯磺酰)-β-D-赤霉烯-4(Z)-烯基呋喃核糖核苷]嘧啶(3)。将2或3用水三氟乙酸处理,得到相应的去保护乙烯基(5)或烯基(6)砜,5在碱性溶液中容易转化为6。将2与硼氢化钠、硫代甲醇钠或氨处理,发生共轭加成(在乙烯基砜的C5′位置),得到5′-羟基、5′-甲硫基或5′-氨基-5′,6′-二去氧-6′-(p-甲苯磺酰)核苷。5′-取代对映异构体被去保护、分离,并通过X射线晶体学确定了5′-氨基衍生物的构型。关键词:烯基砜,氨基核苷,5′,6′-二去氧核苷,核苷,脲苷,乙烯基砜。