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The 1H NMR spectrum of 5-nitroindole (D2O exchanged) shows 5 resonances (d 8.7, d 8.0, d 7.7, d 7.4 and d 6.6 ppm). Given below is a schematic representation of the NOESY spectrum of 5-nitroindole, where the shaded circles represent cross peaks in the two-dimensional spectrum. (i) Explain how the NOESY spectrum can be used to assign the signals in the 1H spectrum. (ii) Assign the resonances for H2, H3, H4, H6 and H7. Answer |
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The 1H NMR spectrum of 2,3-dihydrofuran (F) shows resonances at d 2.6, d 4.2, d 4.9, d 6.2 PPM. Given below is a schematic representation of the COSY spectrum of (F). The 13C spectrum of (F) contains resonances at d 28.5, d 68.6, d 98.4 and d 145.0 PPM. Explain how you could use the COSY and the C-H correlation spectrum to assign the 1H and 13C spectra (i.e. establish which 13C and 1H spectrum belongs to which specific site in the molecule.) Answer |
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