CHEM 2320-2
Test 2 Answers
Dr. Bachrach
Oct. 17, 2012

1) Provide the IUPAC name of the following compounds.

a)

(2R)-2,6-dimethyl-N-phenylhept-5-enamide

b)

(4S)-4-ethoxycycloheptane-1,3-dione

2) Starting with compound I, prepare compound II. You may use any inorganic compound you wish and any alkyl halide as additional sources of carbon.

3) A compound with molecular formula C6H10O2 has the 1H NMR and 13C NMR spectrum below. Identify the structure of the compound. For the 1H NMR spectrum, identify the H source of each signal.

The molecular formula tells us that there are 2 degrees of unsaturation.

Peak A (at 12ppm) tells us there is a COOH group, and that takes care of one degree of unsaturation.

Peaks B and C (7.0ppm and 5.9ppm) are from an alkene, so that’s the other degree of unsaturation – and there are no rings.

Peak F (0.9ppm) is a methyl group with a CH2 neighbor (it’s a triplet). So that integral is for 3 Hs, and the integral for Peak A is for 1 H. That means peak B and peak C are each 1 H, and it looks like peak D and E are for 2 Hs – so that sums up A+B+C+D+E+F=1+1+1+2+2+3=10!

Peak C (5.9ppm) is split into a doublet so it has one neighbor, meaning the following are possible

Where the R groups cannot be hydrogens.

Since there are 6 peaks in the 13C NMR, all six carbons in the molecule are different – there is no symmetry in the molecule, so the first option above doesn’t seem likely, especially given the integrals for the remaining hydrogens. For the other two options, if the carboxylate group is attached to the alkene, that would allow for the right splitting of peak C:

So, now looking at peak B, it is split into a doublet by Peak C, and the NMR shows a doublet of triplets, so there much be a CH2 group right next to it – and there is a methyl at the end so that allows us to say that the compound is

I gave full credit for either the cis or trans isomer – the large splitting of the vinyl peaks (Peak B and C) however tells us it is trans.

4) Provide the product(s) of the following reactions. If there is more than one product, indicate the major product.

a)

b)

c)

6) Provid the mechanism for the base hydrolysis (saponification) of compound III.

5) Provide the reagent(s) to perform the following transformations.

a)

b)

c)

d)