Convenient synthesis of 3',5'-cyclic diguanylic acid (cdiGMP).

We herein report a convenient synthesis of 3',5'-cyclic diguanylic acid (cdiGMP) through the modified H-phosphonate chemistry. The 1-(4-chlorophenyl)-4-ethoxypiperidin-4-yl (Cpep) group was used as protecting group for the 2'-hydroxy functions of ribonucleosides. Homogeneous cdiGMP was obtained after removal of the protecting groups.