Since the phosphorolysis of ribosyl and 2ʹ-desoxyribosyl nucleosides is under tight thermodynamic control, we were then interested in the thermodynamics and reversibility of the phosphorolysis of 1a to enable a diversification of the scaffold via transglycosylation. Time-course experiments with 1a and varying excesses of phosphate revealed incomplete conversion of the substrate, with the equilibrium positions being consistent with an equilibrium constant K of 0.16 (at 60 °C and pH 9, Figure ). Further experiments to monitor the equilibrium at 75 °C and 90 °C revealed that the phosphorolysis of 1a has an apparent reaction enthalpy Δ ′ of 8.9 kJ mol -1 and an apparent reaction entropy Δ ′ of 11.7 J mol -1 K -1 (Figure ). Interestingly, these values closely resemble the equilibrium constants and thermodynamic parameters of the phosphorolysis of uridine, indicating that substitutions distant from the anomeric center have little influence on the equilibrium thermodynamics of nucleoside phosphorolysis. These results also pointed to the reversibility of this transformation, opening the door for transglycosylation reactions from the sugar phosphate 3 to yield other nucleosides.