[Synthesis and characteristics of modified oligodeoxyribonucleotides containing 2'-O-(2,3-dihydroxypropyl)uridine and 2'-O-(2-exoethyl)uridine].

A new uridine derivative, 2'-O-(2,3-dihydroxypropyl)uridine, and its 3'-phosphoramidite were obtained for direct introduction into oligonucleotides during automated chemical synthesis. Oligonucleotides 10 to 15 nt long harboring 2'-O-(2,3-dihydroxypropyl)uridine residues were synthesized; periodate oxidation of these oligomers gave oligonucleotides containing 2'-O-(2-oxoethyl)uridine residues. The presence of a reactive aldehyde group in 2' position of the carbohydrate moiety was confirmed by the interaction with p-nitrophenylhydrazine and methionine methyl ester. The thermostability of DNA duplexes containing modified units is practically indistinguishable from that of the natural analogues.