An improved phosphoramidite approach for the chemical synthesis of 3′,5′-cyclic diguanylic acid

Abstract

3′,5′-Cyclic diguanylic acid (c-di-GMP) plays important roles as a signaling and effector molecule in prokaryotes as well as inducing innate and adaptive immune responses in mammalian cells through activation of cell death pathways. An improved phosphoramidite method for the synthesis of c-di-GMP is reported herein. The method is based on the use of an unprecedented 5′-O-formyl ester, which can efficiently and chemoselectively be cleaved from a dinucleotide phosphoramidite intermediate to permit a 1H-tetrazole-mediated cyclocondensation reaction leading to a fully protected c-di-GMP product in a yield of 78%. The native c-di-GMP is isolated in an overall yield of 36% based on the commercial ribonucleoside used as starting material.