Synthetic study on carbocyclic analogs of cyclic ADP-ribose, a novel second messenger: An efficient synthesis of cyclic IDP-carbocyclic-ribose

An efficient synthesis of cyclic IDP-carbocyclic-ribose, as a stable mimic for cyclic ADP-ribose, was achieved. 8-Bromo-N1-carbocyclic-ribosylinosine derivative 10, prepared from N1-(2,4-dinitrophenyl)inosine derivative 5 and an optically active carbocyclic amine 6, was converted to 8-bromo-N1-carbocyclic-ribosylinosine bisphosphate derivative 15. Treatment of 15 with I2 in the presence of molecular sieves in pyridine gave the desired cyclic product 16 quantitatively, which was deprotected and reductively debrominated to give the target cyclic IDP-carbocyclic-ribose (3).