1	DUA	2',5'-dideoxy-5'-(tritylamino)uridine	1.000
2	DU3	2',5'-dideoxy-5'-[(diphenylmethyl)amino]uridine	0.829
3	DU4	2',5'-dideoxy-5'-[(diphenylmethyl)(methyl)amino]uridine	0.806