Answer Happy

Shown below is the 'H NMR spectrum of N.N-dimethyl-3-ammonium-2- methylpropiophenone chloride in CDCI). The peak listing in Hz is provided for the peaks below 5 ppm CANO 300 MHR spectrum CDG, SOURCE Maich Spectra Cotodiohieich CT 26 45 32 135 130 81 0 75 4.48 ppm 383 ppm 2.91 ppm 873.9 870.0 1359.6 13575 13515 1349.3 13433 1341.2 1335.3 1333.2 1327.2 1325.1 1164.6 1158.4 1152.5 11503 1144.2 1136.1 3.19 ppm 966.0 963.9 961.7 953.9 951.8 949,7 2.64 ppm 793.8 789.9 1.33 ppm 4023 394.4
Assign each hydrogen to the corresponding peak in the 'H NMR spectrum. HO HO W- HO HOCH CH'S CH39 het HO Peak (ppm) Assignment(s) 12.40 8.07 7.63 752 4.48 3.83 3.19 2.91 2.64 1.33
b. For each peak in the alkyl region (1.33-4.48 ppm), what is the splitting pattern? Use the peak list above to determine the coupling constant(s) for each peak. For each ) value, indicate the coupled protons using standard notation (J. 2 = X.X Hz). J values Peak splitting pattern 4.48 3.83 3.19 2.91 2.64 1.33 c. What coupling interactions account for the apparent triplet of triplet pattern for the peak at 7.63 ppm?
d. The coupling interactions observed indicate that this molecule has a strong preference for a particular conformation in weakly polar solvents (CDCI). Fill in the substituents on the Newman projections shown below for the CC and C-N bond to show the likely conformation that would be consistent with the coupling values determined in partc. Use the same H numbering given in part a. Explain how the coupling values are consistent with your proposed conformations. ch NHMez NHMez H® HC Ph 19 Ph нб