Chemistry of the Hypermodified Base from Mammalian Phenylalanine Transfer Ribonucleic Acids

1.通过1-苄基-7-(三苯基膦甲基)Y与异丁醛的Wit反应、OSO_4氧化反应、(CoCl2)_2处理生成环状碳酸酯以及Pd-C.2催化氢解等一系列反应，合成了标题荧光碱的模型化合物。1-苄基-7-碘代苯与(S)-N-(甲氧羰基)乙烯基甘氨酸的Heck反应和甲基化反应为合成目标化合物的关键中间体of‘(S)-(E)-1-benzy1-7-[3-methoxycarbonyl-3-(methoxycarbonyl)amino-1-butenyl]wye，提供了一种改进的方法。中间体用OSO4氧化生成了一对二醇的非对映异构体，经X-射线分析确定了主要产物为(S，S，S)构型。根据上述模型实验，将二醇转化为标题碱的两个替代品[R-(R^*，S^*)]-和[S-(R^*，R^*)]-羟基wybuine。目前正在调查羟基丁酸异构体的化学性质，并从天然来源中分离出碱基。

1. The synthesis of a model compound for the title fluorescent base has been established by a series of the reactions: the Witting reaction between 1-benzy1-7-(triphenylphosphoniomethyl)wye and isobutyraldehyde, oxidation with OsO_4, cyclic carbonate formation by treatment with (COCL)_2, and catalytic hydrogenolysis over Pd-C.2. The Heck reaction of 1-benzy1-7-iodowye with (S)-N-(methoxycarbonyl)vinylglycine followed by methylation has provided an improved method for the synthesis of'(S)-(E)-1-benzy1-7-[3-methoxycarbonyl-3-(methoxycarbonyl)amino-1-butenyl]wye, the key intermediate for the synthesis of the target compounds. Oxidation of the intermediate with OsO_4 gave a pair of the diastereomers of the diols and the (S,S,S) configurations were assigned to the major product by means of X-ray analysis. According to the model experiments mentioned above, the diols were transformed into [R-(R^*,S^*)]- and [S-(R^*,R^*)]-hydroxywybutine, two alternatives for the title base.3. Investigation of the chemical properties of the isomers of hydroxywybutine and isolation of the base from natural sources are in progress.