[ 18f ] -5-fluorocytosine-arabinoside ( 2 ) and [ 18f ] -5-fluorocyclocytidine ( 4 ) were prepared by reaction of [ 18f ] -acetylhypofluorite with cytosine-arabinoside ( 1 ) or cyclocytidine ( 3 ) in acetic acid and were isolated in an overall radiochemical yield of 20 % and 9 % , respectively .
C0010711
cytosine-arabinoside
C0010557
cyclocytidine