Conversion of uracil derivatives to cytosine derivatives.

摘要

A process is disclosed for producing a 4-0-sulfonyluracil derivative of the formula
<Chemistry id="chema01" num="0001"><Image id="ia01" he="30" wi="37" file="IMGA0001.TIF" imgContent="chem" imgFormat="TIFF" inline="no" /></Chemistry>[wherein R<Sup>1</Sup> is hydrogen, halogen, alkyl and alkoxy, R<Sup>2</Sup> is glycosyl having protected hydroxyls; and -SO<Sub>2</Sub>R<Sup>3</Sup> is an organic sulfonyl] which comprises reacting an uracil derivative of the formula
<Chemistry id="chema02" num="0002"><Image id="ia02" he="29" wi="31" file="IMGA0002.TIF" imgContent="chem" imgFormat="TIFF" inline="no" /></Chemistry>[wherein R<Sup>1</Sup> and R<Sup>2</Sup> are the same above] with an organic sulfonylating agent of the formula R<Sup>2</Sup> S0<Sub>2</Sub>X [wherein R<Sup>3</Sup>S0<Sub>2</Sub> is an organic sulfonyl and X is halogen] in the presence of potassium carbonate. The obtained 4-0-sulfonyluracil is further subjected to amination. The processes are industrially advantageous and produce cytosine derivatives such as cytidine in high yield.