Synthesis of 3',5'-cyclic diguanylic acid (cdiGMP) using 1-(4-chlorophenyl)-4-ethoxypiperidin-4-yl as a protecting group for 2'-hydroxy functions of ribonucleosides.

We herein report a convenient synthesis of 3',5'-cyclic diguanylic acid via the modified H-phosphonate approach. The 1-(4-chlorophenyl)-4-ethoxypiperidin-4-yl (Cpep) group was used as protecting group for the 2'-hydroxy functions of ribonucleosides. Complete unblocking of the fully protected 3',5'-cyclic diguanylic acid gave cdiGMP as a homogeneous compound in an excellent yield.