Synthesis of New Dinucleotide mRNA Cap Analogs Containing 2, 6-Diaminopurine Moiety

The first example of the synthesis of cap analog derivatives having 2, 6-diaminopurine nucleoside has been described. The desired modified cap analogs m7G[5']ppp[5']2-aminoA 6 and m2 7,3'OG[5']ppp[5'] 2-aminoA 7 were obtained from the coupling reaction of imidazolide salt of 2-amino adenosine [5'] monophosphate with its corresponding TEA salt of m7GDP in the presence of ZnCl2 as a catalyst in 73% and 64% yield, respectively. The structures of new cap analogs were confirmed by LC/MS, 1H and 31P NMR.