Electrospray ionization mass spectra of dinucleotide N3′ → P5′ phosphoramidates

Dinucleotide N3′ → P5′ phosphoramidates were synthesized and determined by positive ion electrospray ionization mass spectrometry (ESI-MS), their fragmentation pathways were investigated using tandem mass spectrometric (MS/MS) techniques, and many abundant characteristic fragment ions were found. The results show that multistage ESI-MS is a powerful tool for the structure determination of dinucleotide N3′ → P5′ phosphoramidates.