91Ó°ÊÓ

A compound of unknown structure gave the following spectroscopic data:

Mass spectrum:${\mathbf{M}}^{+}\mathbf{=}\mathbf{88}\mathbf{.}\mathbf{1}$

IR: $\mathbf{3600}\text{ }{\mathbf{cm}}^{-1}$

${}^1\mathbf{H}$NMR: 1.4$\mathbf{δ}$ (2H, quartet, J=7Hz); 1.2$\mathbf{δ}$ (6H, singlet); 1.0$\mathbf{δ}$ (1H, singlet); 0.9$\mathbf{δ}$ (3H, triplet, J=7Hz)

${{}^1}^3\mathbf{C}$NMR: 74, 35, 27, 25$\mathbf{δ}$

(a) Assuming that the compound contains C and H but may or may not contain O, give three possible molecular formulas.

(b) How many protons (H) does the compound contain?

(c) What functional group(s) does the compound contain?

(d) How many carbons does the compound contain?

(e) What is the molecular formula of the compound?

(f) What is the structure of the compound?

(g) Assign peaks in the molecule’s NMR spectrum corresponding to specific protons.

p-Nitrobenzyl alcohol is more acidic than benzyl alcohol, but p-methoxy-benzyl alcohol is less acidic. Explain.

Starting from testosterone (Problem 17-62), how would you prepare the following substances?

a.

b.

c.

d.

Compound A, ${\mathbf{C}}_{10}{\mathbf{H}}_{18}\mathbf{O}$ , undergoes reaction with dilute${\mathbf{H}}_2{\mathbf{SO}}_4$ at$\mathbf{25}\mathbf{°}\mathbf{C}$ to yield a mixture of two alkenes,${\mathbf{C}}_{10}{\mathbf{H}}_{16}$ . The major alkene product, B, gives only cyclopentanone after ozone treatment followed by reduction with zinc in acetic acid. Write the reactions involved, and identify A and B.

Compound A, ${\mathbf{C}}_5{\mathbf{H}}_{10}\mathbf{O}$, is one of the basic building blocks of nature. All steriods and many other naturally occurring compounds are built from compound A. Spectroscopic analysis of A yields the following information:

IR : $\mathbf{3400}\text{ }{\mathbf{cm}}^{-1}$;$\mathbf{1640}\mathbf{\text{ }}{\mathbf{cm}}^{-1}$

${}^1\mathbf{H}\text{ }\mathbf{NMR}$: 1.63$\mathbf{δ}$ (3H, singlet); 1.70$\mathbf{δ}$ (3H, singlet); 3.83$\mathbf{δ}$ (1H, broad singlet); 4.15$\mathbf{δ}$ (2H, doublet, J=7 Hz); 5.70$\mathbf{δ}$ (1H, triplet, J = 7 Hz)

1. How many double bonds and/or rings does A have?
2. From the IR spectrum, what is the identity of the oxygen-containing functional group?
3. What kinds of protons are responsible for the NMR absorptions listed?
4. Propose a structure for A.

Show the products obtained from addition of methylmagnesium bromide to the following compounds:

1. Cyclopentanone
2. Benzophenone (diphenyl ketone)
3. 3-Hexanone