Organic Chemistry II
	Professor Carl C. Wamser
Chem 335 - Winter Term	Quiz 13

1. (3 points) The ortho, meta, and para isomers of the xylenes (dimethylbenzenes) are easily distinguished by C-13 NMR. Explain.

2. (2 points) Identify the compound of formula C12H18 that would have only one singlet in its H-1 NMR (at 2.2 ppm).

3. (5 points) Identify the unknown compound X based on the following.
For each piece of data, indicate what structural conclusions you can draw.
Assign individual peaks in the NMR spectra to specific C’s and H’s.
(s = singlet, d = doublet, t = triplet, q = quartet)

Molecular formula: C4H7BrO IHD =

Mass spectrum: approximately equal peaks at 150 and 152

IR spectrum: strong peak at 1720 cm-1

C-13 NMR spectrum: peaks (ppm) at 25 (q), 30 (t), 35 (t), 210 (s)

H-1 NMR spectrum: peaks (ppm) at 2.1 (s, 3H), 2.5 (t, 2H), 3.1 (t, 2H)

IHD: (10 - 8)/ 2 = 1, there is one double bond or ring.

Mass spectrum: equal peaks at 150 and 152 we have one bromine, also gives molecular weight of the compound.

IR spectrum: Peak at 1720 cm-1 means a carbonyl group in the molecule

C-13 NMR spectrum: # of unique carbons (no symmetry) also coupled protons it so gives the number of protons attached to each carbon.

H-NMR spectrum: Chemical shifts give information about chemical environment, peak multiplicity gives neighboring hydrogens, integrations give # of hydrogens of each type