Table 1.

Selection of chemically synthesized 5-fluoro uracil and 5-fluoro cytosine modified DNA and RNA oligonucleotides^a

No.	Sequencea	Length	Isolated yield		Molecular weight
		(nt)	OD 260 nm	(nmol)	Calculated (amu)	Foundb (amu)
S2	5′-d(TCG TAC CGG AAG GTA CGA ACC dU5FTC CG)-3′	26	88	320	7960.1	7958.8
S2b	5′-d(CCG GAA GGT ACG AAC CdU5FT CCG)-3′	21	78	350	6420.1	6419.1
S4	5′-r(GAC CGG AAG GUC CGC CU5FU CC)-3′	20	68	320	6374.8	6374.9
S4b	5′-r(CGG AAG GUC CGC CU5FU CC)-3′	17	86	500	5395.2	5394.8
S5	5′-r(GAC CGG AAG GUC CGC CU5FU5F CC)-3′	20	66	323	6392.8	6393.1
S5b	5′-r(CGG AAG GUC CGC CU5FU5F CC)-3′	17	27	161	5413.2	5412.8
S6	5′-d(TCG TAC CGG AAG GTA CGA ACdC5F TTC CG)-3′	26	150	550	7974.1	7973.6
S6b	5′-d(C CGG AAG GTA CGA ACdC5F TTC CG)-3′	21	93	420	6434.1	6433.0
S7	5′-r(GAC CGG AAG GUC CGC C5FUU CC)-3′	20	64	310	6374.8	6373.5
S7b	5′-r(CGG AAG GUC CGC C5FUU CC)-3′	17	64	370	5395.2	5394.7

^adU^5F, 5-fluoro 2′-deoxy uridine; dC^5F, 5-fluoro 2′-deoxy cytidine; U^5F, 5-fluoro uridine; C^5F, 5-fluoro cytidine.

^bLC-ESI MS.