Fall Workshop #9

Question #1

Identify the compound from the list below with molecular formula of C6H10O that is responsible for the following 13C DEPT data.

Question #2

Draw a splitting diagram for the Hb proton if Jbc = 5 Hz and Jba = 10 Hz.


Question #3

Identify the following compound of molecular formula, C4H8O. HINT: calculate a “U” number!

NOTE: the peak cluster at 6.5 ppm is a doublet of doublets (of triplets); at 4.1 ppm is a doublet of doublets; at 4.0 ppm is a doublet of doublets – see pattern close-ups below, noting the relative SPACINGS:

Question #4

Choose one molecule from the list below and sketch what you think the proton and carbon NMR spectra might look like. Be sure that you place peak clusters at their appropriate chemical shifts and that you estimate the integral values. Also, describe the splitting pattern you would expect to observe for each unique proton set. Be able to explain how you arrived at your expected pattern. Remember, that integrals and splitting are for 1H-NMR only.


Question #5

Using the spectroscopic reference information that is available in “SAM” as well as in Chapter 16 of the Jones text, propose an organic structure that is consistent with the spectral data shown below. Be sure to discuss as a group the major pieces of information and how the information is used to derive the structure.


Question #6

Identify the following compounds as aromatic or not aromatic. Be sure to fill in all lone electron pairs and hydrogen atoms to complete the Lewis structures before you begin (be careful of sites where charges reside). In the process:

a.  Indicate what types of orbitals any lone electron pairs reside in (e.g. sp3, sp2, sp, or p).

b.  Indicate whether lone electron pairs should be included in the calculation of Huckel’s number (4n +2 p electrons) or not.

c.  Go through the aromaticity rules to determine if the system is aromatic (cyclic, conjugated, planar, Huckel's rule, Frost circle).

d. If a compound is not aromatic, provide an explanation as to why it is so.

Question #7

Draw each of the following aromatic molecules (Refer to page N9 of the purple book as well as pages 643-645 of Jones – you may also find the structures in the following figures helpful: Figs. 13.53, 13.56, 13.61, 13.62, 13.66, 13.85).

a. m-bromoaniline

b. 2,4,6-trinitrotoulene

c. 2,3-dimethylthiophene

d. p-aminobenzoic acid (PABA)

e. 3-isopropylpyrrole

Question #8

Name each of the following aromatic molecules (Refer to page N9 of the purple book as well as pages 643-645 of Jones – you may also find the structures in the following figures helpful: Figs. 13.53, 13.56, 13.61, 13.62, 13.66, 13.85).