Organic Chemistry

Problems 139

28. Give the structure of a hydrocarbon that has six carbon atoms and
    a. three vinylic hydrogens and two allylic hydrogens. c. three vinylic hydrogens and no allylic hydrogens.
    b. three vinylic hydrogens and one allylic hydrogen.


29. Draw the structure for each of the following:
    a. -1,3,5-tribromo-2-pentene c. -1,2-dibromo-3-isopropyl-2-hexene e. 1,2-dimethylcyclopentene
    b. -3-methyl-2-heptene d. vinyl bromide f. diallylamine


30. a. Give the structures and the systematic names for all alkenes with molecular formula ignoring cis–trans isomers.
    (Hint:There are 13.)
    b. Which of the compounds have Eand Zisomers?


31. Name the following compounds:
    a. c. e.

b. d. f.

32. Draw curved arrows to show the flow of electrons responsible for the conversion of the reactants into the products:


33. In a reaction in which reactant A is in equilibrium with product B at 25°C, what are the relative amounts of A and B present at
    equilibrium if at 25°C is
    a. b. c. d.


34. Several studies have shown that a precursor of vitamin A, may play a role in preventing cancer. has a
    molecular formula of and contains two rings and no triple bonds. How many double bonds does it have?


35. Tell whether each of the following compounds has the Eor the Zconfiguration:

a. c.

b. d.

36. Squalene, a hydrocarbon with molecular formula is obtained from shark liver. (Squalusis Latin for “shark.”) If squalene is
    an acyclic compound, how many bonds does it have?


37. Assign relative priorities to each set of substituents:
    a. d.
    b. e.
    c.


38. Molly Kule was a lab technician who was asked by her supervisor to add names to the labels on a collection of alkenes that showed
    only structures on the labels. How many did Molly get right? Correct the incorrect names.
    a. 3-pentene e. 5-ethylcyclohexene i. 2-methylcyclopentene
    b. 2-octene f. 5-chloro-3-hexene j. 2-ethyl-2-butene
    c. 2-vinylpentane g. 5-bromo-2-pentene
    d. 1-ethyl-1-pentene h. (E)-2-methyl-1-hexene

¬CH 2 CH 2 CH 3 , ¬CH(CH 3 ) 2 , ¬CH“CH 2 , ¬CH 3

¬CH 2 CH 2 OH, ¬OH, ¬CH 2 Cl, ¬CH“CH 2 ¬COCH 3 , ¬CH“CH 2 , ¬Cl, ¬C‚N

¬Br, ¬I, ¬OH, ¬CH 3 ¬CH 2 NH 2 , ¬NH 2 , ¬OH , ¬CH 2 OH

p

C 30 H 50 ,

O

CH 3 C CH 2 Br

CH 2 CH 2 Cl

C

HOCH 2

C

HC C CH 2 CH CH 2

CH(CH 3 ) 2

C C

H 3 C

CH 2 Br

CH 2 CH 2 CH 2 CH 3

C

Br

C

CH 2 CH 3 H 3 C

CH 2 CH 2 Cl

C

CH 3 CH 2

C

H 3 C

C 40 H 56

b-carotene, b-Carotene

2.72 kcal>mol? 0.65 kcal>mol? -2.72 kcal>mol? -0.65 kcal>mol?

¢G°

CC

HH

HBr

H O− ++H H H 2 O + Br−

H

H

C

H

C

H

Br

C 6 H 12 ,

(Z)

(Z) (E)

BRUI03-109_140r4 24-03-2003 11:53 AM Page 139