Abstract: An oligonucleotide wherein at least one nucleotide unit of the oligonucleotide is conjugated with a moiety selected from the group consisting of: (a) amino acids; (b) dipeptide mimics; (c) sugars; (d) sugar phosphates; (e) neurotransmitters; (f) poly-hydroxypropylmethacrylamide; (g) dextrans; (h) polymaleic anhydride; (i) cyclodextrins; (j) starches; and (k) polyethyleneimine. The oligonucleotides may be employed for binding to an RNA, and DNA, a protein, or a peptide to inhibit or prevent gene transcription or gene expression, to inhibit or stimulate the activities of target molecules, or the oligonucleotides may be employed as diagnostic probes for determining the presence of specific DNA or RNA sequences or proteins.

Abstract: An oligonucleotide wherein at least one nucleotide unit includes a phosphonate moiety having the following structural formula: ##STR1## , wherein X is a zwitterionic moiety. Such oligonucleotides have improved cellular uptake capabilities and improved resistance against nuclease activity.

Abstract: Novel 5'-deoxy-5-fluoropyrimidine nucleosides are potent anti-tumor agents. Preferred compounds are 5'-deoxy-5-fluorocytidine and 5'-deoxy-5-fluorouridine.