Tetraethyldicyanoborane pyrophosphate (2) and 3'-(diethylphosphite-cyanoborano)-5'-dimethoxytrityl.N4-benzoyl-deoxycytidine (3) have been synthesized in 70% and 76% yields, respectively. The compatibility of
the substituted boranophosphates with common protecting groups is hereby demonstrated.Boron containing biologically active compounds, such as nucleosides and nucleotides 1-6 and amino acids 7-9
are important due to their potential therapeutic activity, research and diagnostic applications. Many boron
containing compounds have shown promising activity as anticancer, 1, 11, 12 antiinflammatory,13 and antiosteoporotic 13agents. Oligonucleotdes in which a non-bridging oxygen atom is replaced by a borane(BH3) group are a very important class of modified nucleic acids. 1, 3, 14-16 The BH3 group is isoelectronic with
oxygen in natural oligonucleotides and isoelectronic and isostructural with the oligonucleotide methyl
phosphonates, which are nuclease resistant. On the other hand, the α-borano triphosphates are good
substrates for DNA polymerases and incorporation of boranophosphates into DNA causes an increase in the
resistance to exo- and endonucleases 2, 17a as compared to non-modified DNA. There are also notable
applications of the α-borano triphosphates in PCR sequencing 17a and nucleic acid detection 17b.
