Optimized Synthesis of Fmoc/Boc-Protected PNA Monomers and their Assembly into PNA Oligomers.

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Continuous advancement of application of peptide nucleic acid (PNA) oligomers encouraged exploration of rapid and efficient synthesis of PNA monomers and oligomers. Among the PNA monomers developed, only a few are commonly used in automated PNA synthesis. Herein, we report short and efficient protocols suitable for large-scale synthesis of Fmoc/Boc-protected PNA monomers with advantageous solubility properties; these also facilitate purification due to the traceless nature of the Boc protecting group. Initially, several coupling reagents were screened for assembly of a pentamer containing all four nucleobases, and then the most promising reagents were tested in the synthesis of a decamer. The Fmoc/Boc-protected monomers proved compatible with both manual synthesis and assembly on an automated peptide synthesizer at room temperature or at 40 °C. As compared to the commonly used coupling agent, 1-[bis(dimethylamino)methylene]-1H-1,2,3-triazolo[4,5-b]pyridinium 3-oxide hexafluorophosphate (HATU), both 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate (HBTU) and [ethyl cyano(hydroxyimino)acetato−O2]tri-1-pyrrolidinylphosphonium hexafluorophosphate (PyOxim) proved more favorable, with the latter being superior. A previously reported side reaction of guanine bases in the presence of benzotriazol-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate (PyBOP) was not observed with the phosphonium salts.

Original languageEnglish
JournalEuropean Journal of Organic Chemistry
Issue number19
Pages (from-to)2792-2801
Number of pages10
Publication statusPublished - 2021

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© 2021 Wiley-VCH GmbH

    Research areas

  • Building blocks, Heating automation, Oligomerization, Peptide nucleic acids, Solid-phase synthesis

ID: 273132184