Fig. 1. 13C NMR spectra showing the progress of the reaction in comparison with standards and control experiments; (a) standard sample of adenosine-3′-phosphate 2, (b) reaction mixture when the yield of cyclisation of 2 was 50%, (c) reaction mixture when the yield of cyclisation of 2 was 90%, (d) standard sample of adenosine-2′,3′-cyclic phosphate 3, (e) control experiment of glyoxylate 4 + cyanamide 1, (f) control experiment of glyoxylate 4 + urea 7.
