New photoacids in microarray synthesis of oligonucleotides

Photochemical activity of thiophene oxime esters and of sulfonium salt tris[4-(4-acetyl phenyl)sulfanylphenyl]sulfonium tetrakis(2,3,4,5,6-pentafluorophenyl)boranuide (photoacid generator 290 [PAG 290]) was investigated in a reaction forming a trityl cation. Quantum yields of photoacid phototransformation reactions and of photodetritylation of 50-O-(4,40-dimethoxytrityl) thymidine were determined. Then, [(Z)-[(3Z)-3-[cyano(o-tolyl)methylene]-2-thienylidene]amino] 2,4,6-triisopropylbenzenesulfonate (H 365) and PAG 290 were used as detritylation photoactivators in a procedure of oligonucleotide synthesis on a microchip synthesizer prototype, and several oligonucleotides were synthesized. At the stage of oligonucleotide chain extension, the yield was 94-96%. The tested photoacids can be successfully applied to microchip synthesis of oligonucleotides.(c) 2023 The Authors. Published by Elsevier B.V. on behalf of King Saud University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).