P-Diphenyl P'-morpholino pyrophosphorochloridate was prepared from morpholino phosphorochloridate and diphenylphosphate and used for the phosphorylation of isopropylidene-adenosine, -uridine, -N⁶-dimethyladenosine and 9-(4'-hydroxybutyl) adenine. AMP, UMP, N⁶-dimethyl-AMP and 9-(4'-hydroxybutyl) adenine 4'-monophosphate was obtained in 33∼60% isolated yield. By the reaction of products obtained in the phosphorylation of 2', 3'-di-O-acetyladenosine and 3'-deoxythymidine with this reagent, with pyrophosphate salt, ATP and 3'-deoxythymidine 5'-triphosphate were synthesized in good over-all yield.