Chemistry of the Hypermodified Base from Mammalian Phenylalanine Transfer Ribonucleic Acids

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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.