PROCESSES FOR PREPARING 4'AZIDO NUCLEOSIDE DERIVATIVES

摘要

A process for the preparation of a 4'-azido-2',3',5'-triacyl-nucleoside compound (I;B=B1; R<1> is R<1a>CO-and R<2> is R<2a>CO-) or a 4'-azidonucleoside compounds (I; B is B1 or B2 and R<1> and R<2> are hydrogen and acid addition salts thereof) wherein R<1a> and R<2a> 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 R<3> 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, R<2a>C(O)OOH, an acid R<2a>C(O)OH and a phase transfer catalyst and interconverting a uridine B1 to a cytosine B2. The present process provides the 4'-azidonucleosides safely and selectively in high purity with increased efficiency.