Synthesis of 5-hydroxymethyl-, 5-formyl-, and 5-carboxycytidine-triphosphates and their incorporation into oligonucleotides by polymerase chain reaction.

The synthesis of the triphosphates of 5-hydroxymethyl-, 5-formyl-, and 5-carboxycytidine and the incorporation of these building blocks into long DNA fragments using the polymerase chain reaction (PCR) are reported. In this way DNA fragments containing multiple hmC, fC, and caC nucleobases are readily accessible.