Y. Wu, M. Zhou, K. Chen et al.
Chinese Chemical Letters 32 (2021) 1675–1678
supported by the in situ Fourier transform infrared (FT-IR)
characterization on the 1:1 molar ratio mixture of cyclohexyl-
NNCA and KHMDS, based on the disappearance of characteristic
peaks for two carbonyl groups on the NNCA monomer ring at
Natural Science Foundation of Shanghai (No. 118ZR1410300), the
National Key Research and Development Program of China (No.
2016YFC1100401), the National Natural Science Foundation of
China for Innovative Research Groups (No. 51621002), Program of
Shanghai Academic/Technology Research Leader (No. 20XD142
1400), Research program of State Key Laboratory of Bioreactor
Engineering, the Fundamental Research Funds for the Central
Universities (No. 22221818014).
À1
À1
1
864 cm
and 1771 cm , and the appearance of peaks at
À1
À1
1678 cm and 1574 cm for compound 2, and the appearance of
À1
peak at 1744 cm for compound 3. The HRESI-MS characterization
also supported our proposed mechanism by observing the peaks
for compound 3 at m/z of 297.2181 and 319.2001.
When the obtained polypeptoids are subjected to purification,
water in solvent could cause hydrolysis of C-terminal unreacted
NNCA ring to give a C-terminal carboxylate, and the protonation
and decarboxylation of N-terminal N-carbamate to give an N-
terminal amine, which is confirmed by the MALDI-TOF mass
characterization on the purified cyclohexyl-NNCA polypeptoid for
the observation of high intensity peaks at m/z of 613.3, 752.5, 891.6
Appendix A. Supplementary data
References
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Fig. 5a). Still we observed peaks of compounds a3, b3, c3, d3 from
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