derivatives of such related substances as cytosine , uracil , thymine , 6-methyl-uracil , 5-ethyluracil , 5-propyluracil , 5-isopropyluracil , 5-cyclopropyluracil , 5-allyluracil , 5,6-trimethyleneuracil , 6-cyclopropyluracil , 5-cyclobutyluracil and 5-tert-butyluracil have been separated on a column of spheron p-300 .
C0040087
thymine
C0041917
uracil