Preparation of 2'-hydrazino oligonucleotides and their reaction with aldehydes and 1,3-diketones

New N-substituted hydrazones, derivatives of uridyl aldehyde

N-substituted isomeric hydrazones of uridyl aldehyde have been synthesized. The occurrence of the dominant E isomers with respect to the azomethine group was confirmed by means of NMR spectroscopy. Synthesized hydrazones feature an acetonide moiety as a protection of two hydroxyl groups on the ribose part. The attempt to remove the protecting group resulted in an azo-hydrazone tautomeric mixture. The described compounds may be valuable chiral ligands for metal chelation. Assessment of manganese(II) ion affinity to one selected hydrazone was performed.

DNA or RNA oligonucleotide 2'-hydrazides for chemoselective click-type ligation with carbonyl compounds

An efficient method for the synthesis of DNA or RNA oligonucleotide 2'-hydrazides is described. Fully deprotected oligonucleotides containing a hydrazide group at the 2'-position of a uridine residue were obtained by a novel two-step procedure: periodate cleavage of an oligonucleotide with 1,2-diol group followed by conversion of the aldehyde to hydrazide with an extended linker arm using a homobifunctional reagent succinic dihydrazide and NaBH(3)CN. The resulting oligonucleotide 2'-hydrazides were efficiently conjugated by a click-type reaction at acidic pH to aliphatic or aromatic aldehydes with or without NaBH(3)CN reduction to afford novel 2'-conjugates.