Improved synthesis of 32P-labelled 3′,5′-cyclic AMP, 3′,5′-cyclic GMP and other 3′,5′cyclic ribo- and deoxyribonucletodies of high specific activity

A general procedure is described for the two-step chemical synthesis from ³²P]orthophosphoric acid of the eight common ribo- and deoxyribonucleoside 3′,5′-cyclic monophosphates. The method is simple and reliable and both steps are carried out in the same reaction flask without an intermediate purification step. ³²P-labelled cyclic nucleotides are obtained after paper chromatography in yields of 20–60% relative to starting ³²P]orthophosphoric acid and with a specific activity of greater than 1 mCi/μmole. Alternative methods for the purification of reaction mixtures and for the preparation of ³²P-labelled 3′,5′-cyclic AMP and 3,′,5′-cyclic GMP are described.