# 3.E: Organic Nomenclature (Exercises)

Exercise 3-1 Draw structural formulas corresponding to the following names:

a. 2,7,8-trimethyldecane
b. 2,3,4-trimethyl-4-propylheptane
c. 5-(1,1-dimethylpropyl)nonane
d. 4-(chloromethyl)-5-(1-nitroethyl)decane

Exercise 3-2 Give the IUPAC name for each of the following structures:

a. $$\ce{(CH_3)_2CHCH(CH_3)CH_2CH(CH_3)_2}$$
b. $$\ce{CH_3CH_2CH_2CH(CH_3)CH(CH_2CH_3)CH_2CH_2CH_3}$$
c. $$\ce{CH_3CH_2CH(CH_2CH_2CH_3)CH_2CH(CH_3)_2}$$
d. $$\ce{CH_3CH(CH_3)CH(CH_3)CH(CH_3)CH(CH_3)_2}$$

Exercise 3-3 The following are improper IUPAC names. Determine what is incorrect or ambiguous about the name and give the correct name.

a. 2-methyl-3-propylpentane
b. 3-methyl-3-chloropentane
c. 2,3,3,7,7-pentamethyloctane
d. 3-(1,1-dimethylethyl)pentane

Exercise 3-4 Write structural formulas for each of the following:

a. (2,2-dimethylpropyl)cyclopentane
b. 1,2,3-tri(chloromethyl)cyclopropane
c. 1,4-dicyclohexylcyclooctane
d. 1-(1-methylcyclopropyl)-1,2,2,3,3-pentamethylcyclopropane

Exercise 3-5 Give the IUPAC name for each of the following:

a.

b.

c.

d.

Exercise 3-6 Write structural formulas corresponding to the following IUPAC names:

a. 1,3,6-trimethylcyclohexene
b. 1,2,3,3-tetrachlorocyclopropene
d. 3-methylidenecyclohexane

Exercise 3-7 Give the IUPAC name for each of the following:

a.

b.

c.

d.

Exercise 3-8 Draw structures for the following compounds:

b. 1-cyclodecen-4-yne
c. 5-ethynyl-1,3,6-heptatriene
d. 3-methylidenecyclooctyne

Exercise 3-9 There are nine heptane isomers of formula $$\ce{C_7H_{16}}$$. Write structural formulas for each. Name each by the IUPAC system. (In working a problem such as this, proceed systematically by constructing first the heptane, then all the possible hexanes, the pentanes, and so on. Should you inadvertently duplicate a structure, this will become apparent when you name it; duplicate names usually are easier to spot than duplicate structures.)

Exercise 3-10 Write structural formulas for the eight position isomers of $$\ce{C_5H_{11}Cl}$$. Name each as a chloroalkane.

Exercise 3-11 Name each of the following hydrocarbons by the IUPAC system:

a.

b.

c.

d.

e. $$\ce{(CH_3-CH_2-CH_2-)_4-C}$$

f.

Exercise 3-12 Draw the structure of 1,1-dimethyl-3-(1-methyethyl)cyclohexane four times. In the first structure circle all the primary carbons; in the second, circle all the secondary carbons; in the third, circle the tertiary carbons; in the fourth, circle the quaternary carbons.

Exercise 3-13 Draw the possible primary alkyl or alkenyl groups of formulas:

a. $$\ce{C_5H_{11}}$$ (four)
b. $$\ce{C_5H_9}$$ (eight)

Exercise 3-14 Write structural formulas for the following substituent groups:

a. chloromethyl
b. 1-chloroethyl
c. 3-methylbutyl
d. 1,2-dimethylpropyl
e. 1-methyl-2-propenyl
f. 2-methyl-1-propenyl
g. 1-buten-3-ynyl
h. 2-methylcyclohexyl
i. 2-cyclohexenyl
j. phenylmethyl
k. para-nitrophenyl
l. 2,4-dichlorophenyl
m. propylidene

Exercise 3-15 Name the following substituent groups by the IUPAC system and indicate whether they are primary, secondary, tertiary, or aryl groups:

a. $$\ce{BrCH_2CH_2CH_2}-$$
b. $$\ce{(CH_3CH_2)_3C}-$$
c. $$\ce{CH_3C \equiv CCH_2}-$$

d.

e.

f.

g.

Exercise 3-16 Write structural formulas for each of the following substances:

a. 1-octene
c. 1,2-dimethylcyclobutane
e. 3-chloro-3-methyl-1-butyne
f. cyclooctyne
h. 3-methyl-2-hexen-4-yne
i. (1,1-dimethylethyl)benzene
j. (1-methylpropyl)benzene
k. meta-nitrotoluene
l. 1-phenyl-1-methylcyclohexane
m. (phenylmethyl)cyclohexane

Exercise 3-17 Name each of the following substances by the IUPAC system:

a. $$\ce{(CH_3)_2C=CHCH_3}$$
b. $$\ce{Cl_2C=C(CH_3)_2}$$
c. $$\ce{(CH_3)_2C=C=CHBr}$$
d.

e.

f.

g.

h.

i.

j.

Exercise 3-18 Decide whether the following structures are named correctly according to the IUPAC rules. If a name is incorrect or ambiguous, assign the correct name:

a. 1-ethyl-2-methylbutane

b. $$\ce{Cl_2CHCHCl_2}$$ tetrachloroethane

c. 1-methyl-2-cyclohexene

d. $$\ce{CH_2=CHCH_2Cl}$$ 1-chloro-2-propene

e. 2-ethynyl-2-butene

f. phenylpropane

g. dinitrobenzene

h. $$\ce{(CH_3)_2CHCH_2CH_3}$$ isopentane

Exercise 3-19

a. The major component in the oil obtained from pressing the rinds of oranges and lemons is a hydrocarbon called limonene. It is obtained in commercial quantities from citrus rind and is sold as a flavoring and perfume agent. Name limonene by the IUPAC system.

b. The carbon skeleton of limonene is made up of branched five-carbon repeating segments called isoprene (or isoprenoid) units. Furthermore, limonene has the formula $$\ce{C_{10}H_{16}}$$, which corresponds to two $$\ce{C_5H_8}$$ isoprene molecules linked together.

What is the IUPAC name for isoprene? Indicate the isoprene units in the limonene structure by drawing a dotted line through each of the bonds that joins one isoprene unit to the other.

c. Like limonene, $$\beta$$-carotene and vitamin A have carbon skeletons made up of isoprenoid units. These compounds belong to a class of naturally occurring compounds called terpenes. Mark off the isoprenoid units in $$\beta$$-carotene and vitamin A as you did for limonene.

Exercise 3-20 If you have access to the 1967-71 Eighth Collective Subject Index of Chemical Abstracts, locate the page number in the index where each of the compounds shown in Exercise 2-8 occurs and give the name used. Notice that past Chemical Abstracts indexes do not use completely systematic nomenclature, especially for compounds with only a few carbons, but these indexes will be made completely systematic in the future.

## Contributors

• John D. Robert and Marjorie C. Caserio (1977) Basic Principles of Organic Chemistry, second edition. W. A. Benjamin, Inc. , Menlo Park, CA. ISBN 0-8053-8329-8. This content is copyrighted under the following conditions, "You are granted permission for individual, educational, research and non-commercial reproduction, distribution, display and performance of this work in any format."