Fig. 5
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Tertiary isonitriles efficiently remove TzMe groups from tertiary amines and pyridines. (a) 1H and 19F NMR analysis of the tert-butyl isonitrile (tBuNC)-mediated release of DMFBA from TzMe-DMFBA (6 mM TzMe-DMFBA, 18 mM tBuNC, DMSO-d6/PBS, 1/9, pH = 7.4, 37 °C). (b) HPLC analysis of tBuNC-mediated release of tertiary amine group on the naphthalamide probe (2 mM TzMe-TA-NA, 20 mM tBuNC, DMSO/PBS, 1/9, pH = 7.4, 37 °C). (c) 1H NMR analysis of the release of pyridine from TzMe-Py by tBuNC (6 mM TzMe-Py, 18 mM tBuNC, DMSO-d6/PBS 1/9, 37 °C). (d) HPLC analysis of removal of TzMe from pyridine group on naphthalamide probe by tBuNC (2 mM TzMe-Py-NA, 20 mM tBuNC, DMSO/PBS, 1/9, pH = 7.4, 37 °C). (e) Kinetics of consumption of TzMe-TA-NA and release of TA-NA upon reaction with tBuNC (c(TzMe-TA-NA) = 1 mM; c(tBuNC) = 9 mM, DMSO/PBS, 1/9, pH = 7.4, 37°). (f) Kinetics of consumption of TzMe-Py-NA and release of Py-NA upon reaction with tBuNC (c(TzMe-Py-NA) = 1 mM; c(tBuNC) = 9 nM, DMSO/PBS, 1/9, pH = 7.4, 37°). (g) tBuNC removes the TzMe group from quinoline but not methylimidazole heterocycles (for details, see Figures S21–S23 in the Supporting Information). |