there is a close linear correlation between the log partition coefficient ( pa ) of a series of 2'-deoxyriboside ( dr ) , 2',3'-didehydro-3'-dideoxyriboside ( dder ) , 2',3'-dideoxyriboside ( ddr ) , 3'-fluoro-2',3'-dideoxyriboside ( fddr ) and 3'-azido-2',3'-dideoxyriboside ( azddr ) derivatives of uracil , cytosine , thymine , guanine , adenine and 2,6-diaminopurine and their retention times ( rt ) on a lichrospher 60 rp-8 hplc column ( correlation coefficient r greater than 0.970 ) .
C0041917
uracil
C0040087
thymine