Oligonucleotides that are used in various experiments such as PCR, Next Generation Sequencing or quantitative PCR can be synthesized chemically. In contrast to the natural 5’→3’ synthesis, the chemical synthesis generates the strand in a 3’→5’ direction. The first base is coupled covalently to Controlled Pore Glass (CPG). The cyclic elongation reaction consists of five steps: detritylation, tetrazolactivation, coupling, capping and oxidation (figure 1). The synthesis is automated by a synthesizing machine.
Here, we exemplarily synthesized an RNA 20mer with and without a 5’-dimethoxytrityl protection group, respectively, in a 0.2 μmol synthesis scale.