| 摘要 |
A process for the preparation of a 4~-azido-2~,3~,5~-triacyl-nucleoside compound (I;B=B1; R1 is R1aCO-and R2 is R2aCO-) or a 4~-azidonucleoside compounds (I; B is B1 or B2 and R1 and R2 are hydrogen and acid addition sal ts thereof) wherein R1a and R2a are independently C1-10 alkyl or phenyl optionally substituted with 1 to 3 substituents selected from the group consisting of alkyl, alkoxy, halogen, nitro or cyano and R3 is selected from the group consisting of hydrogen, C1-6 alkyl, C1-3 haloalkyl and halogen, comprising contacting a 5~-iodo compound II with a peracid, R2aC(O)OOH, an acid R2aC(O)OH and a phase transfer catalyst and interconverting a uridine B 1 to a cytosine B2. The present process provides the 4~-azidonucleosides safel y and selectively in high purity with increased efficiency.
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