Uracils, 5-benzoyl, synthesis

Synthesis of nucleosides. Reaction of shylated heterocycles with a protected 1-0-acyl or 1-0-alkyl sugar in 1,2-dichloroethane with either trimethylsilyl perchlorate or trimethylsilyl trifluoromethanesulfonate, (013)3810802-CF3, as catalyst gives nucleosides in high yield. The reaction is formulated for the reaction of silylated uracil (1) with l-0-acetyl-2,3,5-tri-0-benzoyl- 3-D-ribofuranose (2) either at 22 for a prolonged period or for 4 hr. at reflux temperature. The function of the catalyst is to convert the sugar into the glycosyl... 

The previously described 3-C-elhynyM,2-0-isopropylidene-a-D-ribofuranose (see Vol. 28, p. 183, ref. 9) has been converted into tri-O-benzoyl glycosyl acetate 3, using standard chemical transformations, and used as a precursor for the synthesis of the nucleoside l-(3-C-ethynyl-P-D-r/Z>o-pentofuranosyl)uracil, a potent anti-tumour agent. ... 

The synthesis of 1-g-D-arabinofuranosylcytosine and some derivatives has been reviewed. Syntheses reported for other ara-nucleosides include spongo-uridine, ara-tubercidin, and the a- and -anomers of ara-7-deazaguanosine prepared by phase-transfer catalysis. Conventional methods have been used to prepare D-glucofuranose derivatives of uracil and thymine,a g-D-glucopyranosyl derivative of nicotine, and 9-(3,4-anhydro-6-deoxy-a-L-talopyranosyl)-6-benzoyl-adenine from L-rhamnose. ... 

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