Efficient chemical synthesis of -modified guanosine derivatives: a versatile probes for mRNA labeling.

An efficient method for the synthesis of -modified guanosine nucleotides such as -[benzyl--(propyl)carbamate]-guanosine-5'--monophosphate, -[benzyl--(propyl)carbamate]-guanosine-5'--diphosphate, -[benzyl--(propyl)carbamate]-guanosine-5'--triphosphate, and -[benzyl--(propyl)carbamate]--methyl-guanosine-5'--diphosphate, starting from the corresponding nucleotide is described. The overall reaction involves the condensation between the exocyclic amine of guanosine nucleotide with 3-[(benzyloxycarbonyl)amino]propionaldehyde in aqueous methanol, followed by reduction using sodium cyanoborohydride to furnish the corresponding -modified guanosine nucleotide in moderate yield with high purity (>99.5%).