NMR Problems Problem 4: Determine the correct structure from the provided structures and write this structure in the box provided on the NMR spectrum. Students are provided the 'H and C NMR data to use as additional information to solve this problem. O O CHO Structure A Structure B Structure C Structure D Draw the correct structure in the provided box for full credit. HA H H NMR 9.4 ppm 6.6 ppm 2.3 ppm 2.0 ppm 0.9 ppm Splitting Integration Singlet 8 Quartet 8 Quartet 16 Doublet 24 Triplet 24 HE CA C13 195 ppm 149 ppm 146 ppm Cc Co CE DEPT-135 Positive No signal Positive Negative Positive Positive 17 ppm 15 ppm 13 ppm HA H: Hc HD HE 11 10 9 00 8 7 6 5 4 3 2 1 ppm 5