PYRIMIDINE NUCLEOSIDE DERIVATIVES

摘要

The pyrimidine compounds of the present invention are represented by the general formula: and pharmaceutically-acceptable salts thereof. In the above formulae, R1 represents a hydroxyl group or an amino group which may be substituted by an acyl group; R2 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; R3 represents a hydrogen atom or a hydroxyl group; and R4 and R5 each represent a hydrogen atom or together may form a group -R6R7Si-O-SiR6'R7'- (wherein R6, R7, R6' and R7' may be the same or different from one another and each represents an alkyl group having 1 to 4 carbon atoms). The compounds of the present invention exhibit excellent antitumor effect or are intermediates for synthesizing useful antitumor agents.