Chemistry 2223B Lecture Notes - Lecture 11: Peptide Synthesis, Coupling Reaction, Phosphodiester Bond

• School: Western University
• Department: Chemistry
• Course: Chemistry 2223B
• Professor: Len Luyt

Document Summary

Nucleic acids (cid:121) 21: chemical synthesis of nucleic acids, like the modern method of peptide synthesis, dna synthesis is also performed using a solid-phase approach. The 5"-oh and 3"-oh ends need protecting groups: we also need a way to condense the phosphoric acid and the alcohol to make a phosphoester. (this is not a carboxylic acid ester, so dcc does not work well). Ho d e r i u q e r s p u o r g g n i t c e o r p t. Nucleic acids (cid:121) 22: 5"-oh protecting group, the 5"-oh group is protected as a dimethoxytrityl (dmt) ether. This ether can be prepared by the sn1 reaction of the 5"-oh with dmt chloride. R = 5" end of nucleotide: the protecting group can be easily removed using trichloroacetic acid (tca). Nucleic acids (cid:121) 24: 3"-oh protecting group, the 3"-oh group of the first unit is linked to a polymer.