Improved synthesis of 5-hydroxymethyl-2′-deoxycytidine phosphoramidite using a 2′-deoxyuridine to 2′-deoxycytidine conversion without temporary protecting groups

Article abstract of DOI:10.1016/j.bmcl.2010.12.098

5-Hydroxymethylcytosine has recently been characterized as the 'sixth base' in human DNA. To enable research on this DNA modification, we report an improved method for the synthesis of 5-hydroxymethyl-2′-deoxycytidine (^5-HOMedC) phosphoramidite for site-specific incorporation into oligonucleotides. To minimize manipulations we employed a temporary protecting group-free 2′-deoxyuridine to 2′-deoxycytidine conversion procedure that utilizes phase transfer catalysis. The desired ^5-HOMedC phosphoramidite is obtained in six steps and 24% overall yield from 2′-deoxyuridine.