Abstract
Four different types of boron-modified nucleotides are reported: P-boranophos-phorothioates, P-cyanoboranophosphates, P-boranomethylphosphonates, and P3′-N5′-boranophosphoramidates. Synthesis of dinucleoside borano-phosphorothioates and nucleoside P-borano-P-thiomonophosphates via a lithium sulfide method is described. The Li2S method also provides an alternative way to synthesize phosphorothioates through a dinitrophenyl P(V) phosphotriester precursor. The mechanism of Li2S substitution was investigated.
ACKNOWLEDGMENT
This work was supported by grants 1R01-GM57693-01 from NIH and DE-FG05-97ER62376 from DOE to B.R.S.