ER 3 | Organic Compounds: Alkanes and Their Stereochemistry
TER
TER 3
3 ||
Problem 3.1
Identify the functionaland
groups in each
of the following molecules:
Organic
Stereochemistry
Organic Compounds:
Compounds:
Alkanes
and Their
Their
Stereochemistry
CHAPTERAlkanes
3 (Lecture
4 HW)
(a) Methionine, an amino acid:
(b) Ibuprofen, a pain reliever:
the number of otherOcarbon atoms attached to the branching carbon
atom. There are
CO2H
Problem
3.1
four
possibilities:
primary (1°), secondary (2°), tertiary (3°), and quaternary (4°).
CH3SCH
2CH
2CHCOHgroups in each of the following molecules:
Identify
the
functional
CH3
R
R
R
R
C
C
(b) Ibuprofen,
a pain reliever:
H
R
R
C
(a) Methionine,NH
an2amino Cacid:
R
H
H
O
H
R
H
CO2H R
H
R
Capsaicin,
pungent substance in chili Tertiary
peppers:carbon (3°)
SCH2the
CHSecondary
CH3(1°)
Quaternary carbon (4°)
Primary(c)
carbon
2CHCOH carbon (2°)
CH3
is bonded to three
is bonded
to four
is bonded to one
is bonded toOtwo
NH2
other carbons.
other carbons.
other carbon.
other carbons.
CH3
O
H3C
The
symbol R is used N
here and throughout organic chemistry to represent a
(c) Capsaicin,
the pungent
in chili
peppers:
generalized
organic
group.Hsubstance
The R group
can
be methyl,
CH3 ethyl, propyl, or any of a
HO
multitude of others. You might
O think of R as representing the Rest of the molecule,
which
Problem
3.2
CH3
O isn’t specified.
H3terms
Cstructures
N
Propose
for simple
molecules
that contain
following functional
groups:used in
The
primary,
secondary,
tertiary,
and the
quaternary
are routinely
(a) Alcohol
(b) Aromatic
(c) Carboxylic
organic
chemistry,
and ring
their
meanings
need to acid
become
second nature. For
H
CH3
(d) AmineHO
(e) were
Both ketone
amine acid
(f) is
Two
double bonds
example,
if we
to say,and
“Citric
a tertiary
alcohol,” we would mean
that
it
has
an
alcohol
functional
group
(
!
OH)
bonded
to a carbon atom that is
Problem
3.3
Problem 3.2
itself
bonded
to three
other
carbons.
(These
other
carbons
may
in turn
connect
Identify
thestructures
functional
groups
inmolecules
the following
model
ofthe
arecoline,
a veterinary
drug
used to
Propose
for
simple
that
contain
following
functional
groups:
to
other
functional
groups.)
control
worms
in(b)
animals.
Convert
intoCarboxylic
a line-bond
structure and a molecular
(a)
Alcohol
Aromatic
ring the drawing(c)
acid
formula
(redAlkanes
! O,(e)
blue
! N).
(d) Amine
Both
ketone
and amine (f) Two doubleOH
bonds
ER 3 | Organic Compounds:
and
Their
OH Stereochemistry
Problem 3.3
R C R
HO2CCH2 C CH2CO2H
Identify the functional groups in the following model of arecoline, a veterinary drug used to
Solution
R
H
control
in animals.
Convert
the drawing
into a line-bond
andother
a molecular
There
areworms
two isomeric
structures.
One
has the connection
CCO
! C2structure
! N, and the
has the
formula
(red
!
O,
blue
!
N).
connection C ! N
! C. class of tertiary
General
Citric acid—a specific
alcohols, R3COH
These
2
pieces . . .
tertiary alcohol
C
1
7
N
H
In addition, we also speak about hydrogen atoms as being primary, secondary, or tertiary.
Primary hydrogen atoms are attached to primary carbons
give . . .
(RCH3), secondary hydrogens are attached to secondary carbons (R2CH2), and
H H H
H H H
tertiary hydrogens
are attached
to tertiary carbons (R
3CH). There is, of course,
these
H
C
C
N
H
and
H
C
N C H
no such thing
as
a
quaternary
hydrogen.
(Why
not?)
structures.
H
H
H
Primary hydrogens (CH3)
Problem
3.4
3.2
Alkanes
and Alkane
IsomersH
Draw structures of the five isomers of C6HCH
14.3
H
H
H
C
H
H
H
Before beginning a systematic study
of the different functional groups, let’s look
CH3CH2CHCH3 =
Problem 3.5
H C C C C H
firstPropose
at thestructures
simplestthat
family
of
molecules—the
alkanes—to develop some general
meet the following descriptions:
H the
H H
ideas
apply
toesters
all hydrogens
families.
We
1.7Hthat
carbon–carbon
Secondary
(CH2saw
) C5in
(a) that
Two isomeric
with the formula
H10Section
O2
single
bond
in
ethane
results
from
!
(head-on)
overlap
of
carbon
sp3 hybrid
(b) Two isomeric nitriles
with the formula C H N
A tertiary hydrogen (CH) 4 7
orbitals.
Ifisomeric
we imagine
joining
three,
four,
five,
more carbon
atoms
by
(c) Two
disulfides
with the
formula
C4H
10S2 or even
Before
beginning
a systematic
study
of the
different
functional
groups,
let’s look
Cfirst
" C single
bonds,
we
can
generate
the
large
family
of
molecules
called
alkanes.
at the simplest family of molecules—the alkanes—to develop some general
3.2 Alkanes and Alkane Isomers
Problem 3.6
H
H to
H all
HWe
Hsaw
H indescriptions?
H that
H Hthe carbon–carbon
ideas
that apply
families.
SectionH1.7
How
many
isomers
are
there
with the
following
Problem
3.7
3
single
bond
in
ethane
results
from
!
(head-on)
overlap
(a)
Alcohols
with
the
formula
C
H
O
Draw
the
eight
5-carbon
alkyl
groups
(pentyl
isomers).
H C H
H C C H
H3 8C C C H
H C C Cof Ccarbon
H . . .sp
and hybrid
so on
(b) Bromoalkanes
with thejoining
formula three,
C4H9Brfour, five, or even more carbon atoms by
orbitals.
If we imagine
Problem
H H
H H
H
H H
H OS
with
the
C4H
C(c)
"
CThioesters
single3.8
bonds,
weformula
can generate
the large familyHof Hmolecules
called alkanes.
8
Identify the carbon atoms in the following molecules as primary, secondary, tertiary, or
Methane
H
quaternary:
H (a)C
Ethane
H H
H CH3 H
C
C
Propane
H H H
H
(b)H
3.3
Groups
H CHAlkyl
3CHCH2CHH
2CHH3
C CHC3CHCH
C H
3
CHH3CHH2CHCH
H 2CH3
HButane
H H
H
C(c)C
H
H
CCHC
3
HCH.3. . and so on
HCHH
H 2CCH3
3CHCH
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CH structure
If you imagine removing a hydrogen atom from an alkane, the partial
that remains is called an alkyl group. Alkyl groups are not stable compounds
themselves, they are simply parts of larger compounds. Alkyl groups are named by
replacing the -ane ending of the parent alkane with an -yl ending. For example,
g.
be
duplicated,
or
Due
some
content
may
suppressed
the
and/or
g. All
All Rights
Rights Reserved.
Reserved. May
May not
notremoval
be copied,
copied, scanned,
scanned,
duplicated, in
in whole
whole
or in
in part.
part.
Due to
to electronic
electronic
rights,
some third
third party
partya
content
may be
begroup,
suppressed from
from
the eBook
and/or eChapter(s).
eChapter(s).
of aororhydrogen
from
methane,
CHrights,
methyl
! CH
, and
4, generates
3eBook
suppressed
suppressed content
content does
does not
not materially
materially affect
affect the
the overall
overall learning
learning experience.
experience. Cengage
Cengage Learning
Learning reserves
reserves the
the right
right to
to remove
remove additional
additional content
content at
at any
any time
time ifif subsequent
subsequent rights
rights restrictions
restrictions require
require it.
it.
removal of a hydrogen from ethane, CH3CH3, generates an ethyl group, ! CH2CH3.
Similarly, removal of a hydrogen atom from the end carbon of any straight-chain
alkane gives the series of straight-chain alkyl groups shown in Table 3.4. Combining an alkyl group with any of the functional groups listed earlier makes it possible
3
Methane
Ethane
pressed content does not materially
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experience. Cengage LearningPropane
reserves the right to remove additionalButane
content at any time if subsequent
rights restrictions require it.
Solution
CH3CHCH3
CH3CHCHCH2CH2CH3
CH3CHCH3
CH3
3CHCHCH
H H HCHH
H H 2HCH2HCHH3 H
3-Isopropyl-2-methylhexane
C
C CH3 C
C
C
H
H
C
C
C
C
C
Problem 3.9
3-Isopropyl-2-methylhexane
Identify the hydrogen atoms H
on
the
compounds
3.8 as primary, secondH H
H H Hshown
H HinHProblem
H
carbon–carbon bonds are arranged anti,
as shown in this model of decane.
3.4 | Naming Alkanes
87
ary, or tertiary.
Problem
3.11
One
final3.10
point:
saying
that one
particular conformer is “more stable” than
Give
IUPAC
names for
the following
compounds:
Problem
another
doesn’t
mean
the
molecule
adopts
anddescriptions:
maintains only the more stable
Draw structures
following
Problem
3.11 of alkanes that meet the
conformation.
At
room
temperature,
rotations
around
! bonds occur so rapidly
(a)The
An
alkane
with for
two
tertiary
(a)
three
isomers
of
C5following
H12 carbons
(b)
CH3
Give
IUPAC
names
the
compounds:
that(b)allAn
conformers
are in equilibrium.
At any given instant, however, a larger
alkane that contains
an isopropyl group
CH3CH2CHCHCH3
percentage
of molecules
be found
a secondary
more
stable
conformation than in a
(c) An alkane
that has onewill
quaternary
andin
one
carbon
(a) The three isomers of C5H12
(b)
CH3
CH3
less stable one.
CH3CH2CHCHCH3
CH3
CH3
(CH3)2CHCH2CHCH3
(CH ) CCH CH CH
Drawing
Newman
Projections(d) 3 3 2 2 CH3
(c)
CH3
CH3
(CH3)2CHCH2CHCH3
(CH3)3CCH2CH2CH
(c)
CH3
(d)
Worked Example
3.4
3.4 Naming Alkanes
Sight along the C1 ! C2 bond of 1-chloropropane, and draw Newman projections of the
In
earlier
times,
when
relatively
few pure organic chemicals
were known, new
most
stable
and least
stable
conformations.
CH3
Problem 3.12
compounds
were named at the whim of their discoverer. Thus, urea (CH4N2O)
Draw
structures corresponding
to the following
IUPAC names:
isStrategy
a crystalline
substance isolated
from urine;
morphine (C17H19NO3) is an
(a)
3,4-Dimethylnonane
(b) 3-Ethyl-4,4-dimethylheptane
The
most
stable
of aafter
substituted
alkane isthe
generally
one in which
analgesic
(painkiller)
named
Morpheus,
Greeka staggered
god of dreams;
and
Problem
3.12 conformation
(c)
2,2-Dimethyl-4-propyloctane
(d)
2,2,4-Trimethylpentane
large
groups
have
an
anti
relationship.
The
least
stable
conformation
is
generally
an
Drawacid,
structures
corresponding
to the
following IUPAC
names: is named from the Latin
acetic
the primary
organic
constituent
of vinegar,
eclipsed
one
in
which
large
groups
are
as
close
as
possible.
(a) 3,4-Dimethylnonane
(b) 3-Ethyl-4,4-dimethylheptane
word
for vinegar,
acetum.
Problem
3.13
(c)
2,2-Dimethyl-4-propyloctane
(d)you
2,2,4-Trimethylpentane
Name
the
eight
5-carbon
alkyl
groups
drew
in Problem
As
the
science
of
organic
chemistry
slowly
grew 3.7.
in the 19th century, so too
Solution
did
the
number
of
known
compounds
and
the
need
for a systematic method of
3.13
Problem 3.14
naming
them.
The
system
of
nomenclature
we’ll
use
in this book is that devised
Namethe
theIUPAC
eight name
5-carbon
groups you
drew in Problem
3.7.
Clalkyl
Give
for
the following
hydrocarbon,
and convert
H3C Cl the drawing into a
byskeletal
the International
Union
of
Pure
and
Applied
Chemistry
(IUPAC, usually
structure.
H
Problem
3.14 H
spoken as eye-you-pac).
Give the IUPAC name for the following hydrocarbon, and convert the drawing into a
H IUPACH system of nomenA chemical
name
typically
has four parts in the
H
H
skeletal
structure.
H
H
clature: prefix, parent,
locant,
and
suffix.
The
prefix identifies the various
CH3
substituent groups in the molecule, the parent selects a main part of the moleMost stable (staggered)
Least stable (eclipsed)
cule and tells
how many carbon atoms are in
that part, the locants give the
positions of the functional groups and substituents, and the suffix identifies the
primary functional group.
Problem 3.15
Make a graph of potential
energy versus
angle of bond
rotation for propane,
Locant
Prefix
Parent
Suffixand assign
values to the energy maxima.
Where are
Problem
3.16the substituents
What are the
How many
What is the primary
andalong
functional
substituents?(isobutane)
carbons?
functional group?
Sight
the C2groups?
! C1 bond, 2-methylpropane
and
(a) draw a Newman projection of the most stable conformation.
(b)Asdraw
Newman
projection
of thegroups
least stable
conformation.
we acover
new
functional
in later
chapters, the applicable IUPAC
(c) make
a graph of energy
versus
angle ofInrotation
around
the C2 ! C1
rules
of nomenclature
will
be given.
addition,
Appendix
A bond.
at the back of this
Alkanes
are
sometimes
referred
to as paraffins,
akJ/mol
word and
derived
from
Latin parum
←
→ H eclipsing
←
→ CHthe
(d)
Since
an
H
interaction
costs
4.0
an
H
3 eclipsing
book
gives
an
overall
view
of
organic
nomenclature
and
shows
how
compounds
affinis,
meaningcosts
“little
Thisrelative
term aptly
describes
their behavior,
interaction
6.0affinity.”
kJ/mol, assign
values
to the maxima
and minimafor
in alkanes
that contain
more than
onefor
functional
group are
named.
(If preferred,
you
can
show
little
chemical
affinity
other
substances
and
are chemically
toparum
most
your
graph.
Alkanes
are
sometimes
referred
to
as paraffins,
a word
derived
from theinert
Latin
3.5 Properties of Alkanes
3.5 Properties of Alkanes
study that reagents.
appendixThey
now.)
the present,inert
let’sbiologically
see how toand
name
branchedlaboratory
areFor
also
arefor
not
often
affinis,
Thisrelatively
term
aptlyrules
describes
alkanes
chain meaning
alkanes “little
and affinity.”
learn some
general
thattheir
arebehavior,
applicable
to all
show
little
chemical
affinity
for
other
substances
and
are
chemically
inert
to
most
compounds.
laboratory
reagents.
They
are
also
relatively
inert
biologically
and
are
not
often
All but the most complex branched-chain alkanes can be named by following
four
steps.
For
ain whole
very
few
compounds,
fifth
step
is Due
needed.
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not
be copied,
scanned,
duplicated,
part.
Due to
electronic
rights,asome
maytobe
suppressed
fromsome
the eBook
and/or
eChapter(s).
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Cengage
Learning.
AllorRights
Reserved.
Mayor
notin
be
copied,
scanned,
or duplicated,
in third
wholeparty
or incontent
part.
electronic
rights,
third party
content
may be suppressed from the eBook and/or eChapter(s).
uppressedEditorial
content does
nothas
materially
thesuppressed
overall learning
experience.
Cengage Learning
the rightexperience.
to remove additional
content atreserves
any timethe
if right
subsequent
rights
restrictions
require
it. time if subsequent rights restrictions require it.
review
deemed affect
that any
content
does not materially
affect thereserves
overall learning
Cengage Learning
to remove
additional
content
at any
STEP 1
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scanned,
duplicated, inhydrocarbon.
whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Find
theor parent
uppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.
(a) Find the longest continuous chain of carbon atoms in the molecule,
and use the name of that chain as the parent name. The longest chain
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.
3.21 Draw a Newman projection along the C2!C3 bond of the following
conformation of 2-butanol.
ER 3 | Organic Compounds: Alkanes and Their Stereochemistry
Problem 3.17
Sight along the C2 ! C3 bond of 2,3-dimethylbutane, and draw a Newman projection of the
most stable conformation.
Exercises
103
Problem 3.18
3.21 a Draw
a projection
Newmanalong
projection
along
the
of theoffollowing
Draw
Newman
the C2 ! C3
bond of
theC2!C3
followingbond
conformation
2,3-dimethylbutane,
andofcalculate
a total strain energy:
conformation
2-butanol.
Additional Problems
Functional Groups
3.22 Locate and identify the functional groups in the following molecules.
CH2OH
(a)
O
(b)
(c)
H
N
NHCH3
C
O
CH3
Additional
Problems
O
(d)
(e)
(f)
CH3CHCOH
Functional
Groups
Cl
2 identify the functional groups in the following molecules.
3.22 LocateNH
and
Gasoline
O
O
(b)
CH2OH
(a)
(c)
HO
N
O
3.23 Propose structures that meet the following descriptions:
C
British
Minister Ernest Bevin once said that “The Kingdom
NHCH
3 Foreign
(a) A ketone with
five
carbons
(b) A four-carbon amide
of Heaven runs on righteousness,
but the Kingdom of Earth runs CH3
(c) A five-carbon ester
(d) An aromatic aldehyde
on alkanes.” (Actually,(fhe
said “runs on oil” not “runs on alkanes,”
(e) A keto ester
) An amino alcohol
(d)
O
but they’re essentially the same.) By far, the major sources of
(e)
(f)
3.24 Propose structures
for are
the the
following:
alkanes
world’s natural gas and petroleum deposits. Laid
CH
CHCOHC
(a)
A
ketone,
H
O
(b)deposits
A nitrile,
3
eons ago,
these
areCthought
4 8Their
5H9N to be derived primarily
TER 3 | Organic Compounds: Alkanes down
and
Stereochemistry
Cl
(c) A dialdehyde,
C
H
O
(d)
A
bromoalkene,
C6H11marine
Br
of tiny single-celled
organisms
4 6 decomposition
2
NH2 from the
(e) An alkane,called
C6H14foraminifera.
(f
)
A
cyclic
saturated
hydrocarbon,
C
H
O Natural gas consists chiefly of methane
6 but
12
Isomers
O
(g) A diene (dialkene),
C5Hethane,
(h)
A ketoand
alkene,
C5H
also contains
propane,
butane.
Petroleum
is a complex
8
8O
3.27 Draw structures
thatof meet
the following
descriptions
(there
are many
mixture
that must
be separated
into
fractions
and
3.23 Predict
Proposethe
structures
that hydrocarbons
meet
descriptions:
3.25
hybridization
of the
thefollowing
carbon atom
in each of the following
possibilities):
then
further
refined
before
it
can
be
used.
esource. It won’t be around forever.
(a)
A
ketone
with
five
carbons
(b)
A
four-carbon
amide
functional
groups: with the formula C H
(a) Three isomers
18
The
petroleum
era began
in aromatic
August
1859,
when the world’s first
TER 3 | Organic Compounds:
and
Their
Stereochemistry
(c)Ketone
AAlkanes
five-carbon
ester
(d)8 An
aldehyde
(a)
(b)with
Nitrile
(c) Carboxylic
acid
(b) Two isomers
the
formula
C
H
O
4
8
oil well was drilled by (f
Edwin
near
Titusville, Pennsylvania.
(e) A keto ester
) An2Drake
amino
alcohol
3.26
Draw
structures
of
the
following
molecules:
The
petroleum
was
distilled
into
fractions
according
to. boiling point, but it was high3.28
Draw the
structures
of the
nine
isomers
of
C7H16
Isomers
3.24
Propose
structures
for
the
following:
(a)
Biacetyl,
C
H
O
,
a
substance
with
of butter;
it contains
boiling kerosene, or lamp
oil,2rather than gasolinethe
thataroma
was primarily
sought.
Literacyno
was
4 6
3.27
Draw
structures
that
meet
the (b)
following
descriptions
(there
are many
(a)
A
ketone,
C
H
O
A
nitrile,
C
H
N
3.29
In
each
of
the
following
sets,
which
structures
represent
the
same
4
8
5
9
rings
or
carbon–carbon
multiple
bonds.
becoming widespread at the time, and people wanted better light for reading compound
than was
possibilities):
(c)
Acandles.
dialdehyde,
Hwas
(d) used
A
C6H
and
which
represent
compounds?
6Oa2too
11
Ethylenimine,
C2CH4different
substance
in in
the
synthesis
ofBr
melamine
available(b)
from
Gasoline
volatile
forbromoalkene,
use
lamps
and
was
initially
consid5N,
(a)
Three
isomers
with
the formula
C8AHcyclic
18
(e)
An
alkane,
C
H
(f
)
saturated
hydrocarbon,
C6H12
6
14
polymers;
it
contains
no
multiple
bonds.
Br
(a)
CH
CH
ered a waste by-product. The world has3 changed greatly since3 those early days, however,
(b)
Two
isomers
with the
formula
C4H
O2 alkene, C H O
8keto
(g)
A
diene
(dialkene),
C
H
(h)
A
5
8
5
8
(c)
Glycerol,
C
H
O
,
a
substance
isolated
from
fat
and
used
in
cosmetics;
it
and it is now gasoline rather
lamp oil that is prized.
3 8 than
3
CH3CHCHCH3
CH3CHCHCH3
CH3CHCHCH3
hasrefining
anthe
" OH
group
on
each
3.28
Draw
structures
of
the
isomers
of
C7H16of
. crude
Petroleum
begins
bynine
fractional
distillation
into of
three
3.25
Predict
hybridization
of carbon.
the
carbon
atom
in oil
each
theprincipal
following
CH3
Br
Br
°C), kerosene
cuts
according
to
boiling
point
(bp):
straight-run
gasoline
(bp
30–200
functional
groups:
3.29 In each of the following sets, which structures represent the same compound
°C). Further distillation under
(bp 175–300
C), andrepresent
heating
or dieselcompounds?
fuelCarboxylic
(bp 275–400
(a) °which
Ketone
(b) oil,
Nitrile
(c)
acid
and
different
reduced (b)
pressure then
lubricating oils and
OHyields HO
HOwaxes and leaves
OH a tarry residue of
Br
CHfollowing
CH3
3.26 (a)
Draw
the structures
ofoil
the
molecules:
3
asphalt.
The
distillation
of crude
is only
the first
step in gasoline
production, however.
(a)CH
Biacetyl,
C4H6out
O2,to
a be
substance
with
ofbecause
butter; of
it engine
contains
no
CH3aroma
CH
CHCHCH
Straight-run
gasoline
turns
a poor fuel
in the
automobiles
knock,
3CHCHCH
3
3CHCHCH
3
3
OH
HO
rings
or
carbon–carbon
multiple
bonds.
an uncontrolled combustion
that can occur
CH3
Br in a hot engine.
Br
(b) Ethylenimine,
C2is
Hthe
N,measure
a substance
usedits
inantiknock
the synthesis
of melamine
5
The octane
number
of a fuel
byduplicated,
which
properties
aresome
judged.
Copyright 2010 Cengage
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Rights Reserved.
May not
be copied,
scanned, or
in whole
or in part. Due
to electronic rights,
third party content may be suppressed from the eBook and/or eChapter(s).
polymers;
it
contains
no
multiple
bonds.
Editorial review has
deemed
that
any
suppressed
content
does
not
materially
affect
the
overall
learning
experience.
Cengage
Learning
reserves
the right
to remove additional content at any time if subsequent rights restrictions require it.
It was recognized
long agoCH
that
straight-chain
hydrocarbons
are
far
more
prone
to
induce
(c)
CH
CH
CH
CH
3
2
3
3
3
(b)
HO from fat and
OH used in cosmetics;
(c) Glycerol,OH
C3H8O3HO
, a substance isolated
(continued)it
CHCH2CHCH3
CH3CH2CHCH2CHCH2OH
CH
3CHan
2CHCH
2CHCH
3 onHOCH
has
" OH
group
each 2carbon.
CH2OH
OH
HO
CH3
All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
3.30 There are seven constitutional isomers with the formula C H O. Draw as
many as you can.
4 10
pressed content does not materially affect the
Learning reserves the right CH
to remove
additional content at any
subsequent
rights restrictions require it.
(c)overall learning experience.
CHCengage
CHtime
3
2CH3
3 if CH
3
CH3CH2CHCH2CHCH3
HOCH2CHCH2CHCH3
CH3CH2CHCH2CHCH2OH
3.31 Draw as many compounds as you can that fit the following descriptions:
CH2OH
CH3
Alcohols
with formula
C4H
(b) Amines
formula
Nthird party content may be suppressed from the eBook and/or eChapter(s).
Copyright 2010 Cengage(a)
Learning.
All Rights Reserved.
May not be copied,
scanned,
in whole or inwith
part. Due
to electronicC
rights,
some
10O or duplicated,
5H13
Editorial review has deemed (c)
that any
suppressed content
not materially
Cengage
Learning
reserves the C
rightH
remove
Ketones
withdoes
formula
C5affect
H10theOoverall learning
(d) experience.
Aldehydes
with
formula
O additional content at any time if subsequent rights restrictions require it.
5 to10
3.30 There
are with
sevenformula
constitutional
the with
formula
C4HC
as
(e) Esters
C4H8O2 isomers(fwith
) Ethers
formula
H10Draw
O
104O.
3.31 (e)
Draw
as many
compounds
can (f
that
fit thewith
following
descriptions:
Esters
with formula
C4H8asOyou
) Ethers
formula
C4H10O
2
CH2OH
(a) Alcohols
with formula C4H10OCH3 (b) Amines with formula C5H13N
Exercises
3.32 Draw
compounds
contain
the
PTER 3 | Organic Compounds:
Alkanes
andthat
Their
Stereochemistry
(c) Ketones
with
formula
C5H10
O following:
(d) Aldehydes with formula C5H10O
AEsters
primary
alcohol
(b)OA tertiary
(e)
formula
C4H
(fnitrile
)with
Ethers
formula
C10
3.30(a)
There
arewith
seven
constitutional
thewith
formula
C4H
O.
Draw as
8 2 isomers
4H
10O
(c)
A
secondary
thiol
(d)
Both
primary
and secondary alcohols
3.37
Draw
a
compound
that:
many
as you can.
General
Problems
3.32 (e)
Draw
compounds
thathydrogens
contain
following:
An
isopropyl
group
(f ) Athe
quaternary
carbon
(a)
Has
nine primary
3.48
For
each
of the
following (b)
compounds,
draw
an following
isomer that
has the same
3.31 (b)
Draw
as
many
compounds
as
you
can
that
fit the
descriptions:
(a)
A
primary
alcohol
A
tertiary
nitrile
Has only primary hydrogens
functional
groups.
Naming
(a)Compounds
with
formula (d)
C4HBoth
O
(b)
Amines
with
formula
C5H13N
(c)
AAlcohols
secondary
thiol
primary
and
secondary
alcohols
10
3.38
Give
IUPAC
names
for
the
following
compounds:
NC5H10O
(c)
Ketones
with
formula
C
H
O
(d)
Aldehydes
with
formula
CH
CH
CH
C
CH
(a)
(b)
(c)
(e)
An
isopropyl
group
(f
)
A
quaternary
carbon
OCH
3.33 Draw and name
all monobromo
derivatives3 of pentane, 3C5H211Br.
5 10
2
3
(e)CH
Esters
with
formula
C
H
O
(f
)
Ethers
with
formula
C
H
CH
CH
H3OC CH3
(a)
(b)
(c)
4 8 2
4 10
3
3
3CHCH
2CHall
2Brmonochloro derivatives of 2,5-dimethylhexane, C8H17Cl.
3.34
DrawCompounds
and
name
Naming
Exercises
CH3compounds
CHCH2CH2CHthat
CH3CHCCH2CH2CH3
3.32 Draw
contain theCH
following:
3
3CH2CCH3
3.33
Draw
and
name
all
monobromo
derivatives
of
pentane,
C
H
Br.
5 11
3.35 Draw
for the following:
(d)
(e)(b)
CH2CO2H
CH3A
CHtertiary
OHalcohol
(a) Astructures
primary
nitrile (f)
2CHO CH
CH3
3
(a)
2-Methylheptane
(b)
4-Ethyl-2,2-dimethylhexane
3.37
Draw
a
compound
that:
3.34 Draw
name all
monochloro
derivatives
of and
2,5-dimethylhexane,
C8H17Cl.
(c) A and
secondary
thiol
(d) Both
primary
secondary alcohols
(c)
(d) 2,4,4-Trimethylheptane
(a)
Has
primary
hydrogens
(e)4-Ethyl-3,4-dimethyloctane
An nine
isopropyl
group
(f ) (e)
A quaternary
carbonCH CH
CH2CHfor
CH3following:
CH
(d)
(f) H3C CH3
3 the
3
2
3
3.35 (e)
Draw
structures
3,3-Diethyl-2,5-dimethylnonane
(f ) 4-Isopropyl-3-methylheptane
(b)
Has
only primary
hydrogens
(a) CH
2-Methylheptane
CH3CH(b)
CH3C CCH2CH2CH3
Naming
Compounds
3CH2CHCH2CH2CHCH3
2CH4-Ethyl-2,2-dimethylhexane
2CHCH2CCH3
3.36
a acid,
compound
3.38
Give
IUPAC
names
for
thebeen
following
compounds:
3.49 Draw
Malic
C4H6Othat:
, has
isolated
from
apples. Because this compound
(c)
4-Ethyl-3,4-dimethyloctane
(d) 2,4,4-Trimethylheptane
5
3.33(a)
Draw
and
all monobromo
derivatives of pentane,
CH3 C5H11Br.
H C CH
Has
onlyname
and tertiaryofcarbons
reacts
with
2primary
molar equivalents
is
a dicarboxylic
acid. (c) H33C CH3 3
(e)
3,3-Diethyl-2,5-dimethylnonane
(fCH
) 34-Isopropyl-3-methylheptane
CH
(a)
(b) base, it
3
Has
noat
secondary
or
tertiarystructures.
carbons
(a)
Draw
least all
fivemonochloro
possible
3.34(b)
Draw
and
name
derivatives of 2,5-dimethylhexane, C8H17Cl.
CH
CHCH
CH2CH3that:
CH3CH2CCH3
CH3CHCCH2CH2CH3
3.36
Draw
a
compound
3
2
(c)
Has
four
secondary
carbons
3.39 Name
the five
isomers
of C6H14alcohol,
.
(b) If malic
acid
is a secondary
what is its structure?
3.35 (a)
Draw
structures
for
the
following:
Has only primary and tertiary carbonsCH
CH3
3
3.40
why
each
the
following
names
is incorrect:
3.50 Explain
Formaldehyde,
H2of
C!O,
known
to
all biologists
because of its usefulness as
(a) Has
2-Methylheptane
(b)
4-Ethyl-2,2-dimethylhexane
(b)
no secondary
or is
tertiary
carbons
(a)
2,2-Dimethyl-6-ethylheptane
(b) (d)
4-Ethyl-5,5-dimethylpentane
a(c)tissue
preservative.
When pure, formaldehyde
trimerizes to give trioxane,
4-Ethyl-3,4-dimethyloctane
2,4,4-Trimethylheptane
(c)
Has
four
CH2secondary
CH3 CH3 carbons (e)
CH3 CH2CH3
(d)
(f) H3C CH3
(c)
3-Ethyl-4,4-dimethylhexane
(d)
5,5,6-Trimethyloctane
C
H
O
,
which,
surprisingly
enough,
has
no
carbonyl
groups. Only one
(e)
3,3-Diethyl-2,5-dimethylnonane
(f
)
4-Isopropyl-3-methylheptane
3 6 3
CH
CH
3CH2CHCH
2CH2CHCH
3 H BrO3CH
2CH2CHCH
2CCH3 Propose a
3C CCH2CH2CH3
(e)
2-Isopropyl-4-methylheptane
monobromo
derivative
(C
) of3CH
trioxane
is possible.
structure
3.36 Draw a compound that: 3 5
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or duplicated, in whole or in part. Due to electronic rights, some third party content
be suppressed from the
and/or eChapter(s).
for trioxane.
CHmay
HeBook
3
3C CH3
3.41
structures
and
give
IUPAC
names
for the
following:
(a)
Haslearning
onlyexperience.
primary
and
tertiary
uppressed content does not materially
affectPropose
the overall
Cengage
Learning
reservescarbons
the right to remove
additional
content at any time if subsequent rights restrictions require it.
diethyldimethylhexane
(b)
alkane
3.51 (a)
The
barrier
to rotationorabout
thecarbons
C "AC(3-methylbutyl)-substituted
bond in bromoethane is 15
kJ/mol
(b) AHas
no secondary
tertiary
3.39
Name
the
five
isomers
of
C
H
.
(3.6
kcal/mol).
(c)
Has
four
secondary
carbons
6
14
ng. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Conformations
→ Br eclipsing
(a)
What
energy
value
can
youreserves
assign
to toan
H←
interaction?
suppressed content does not materially affect
the overall
learning
experience.
Cengage
Learning
the right
remove
additional
content at any time
if subsequent rights restrictions require it.
3.40 Explain why each of the following names is incorrect:
3.42 Consider
2-methylbutane
(isopentane).
theversus
C2–C3
bond:
(b) Construct
a quantitative
diagram ofSighting
potentialalong
energy
bond
rota(a) 2,2-Dimethyl-6-ethylheptane
(b) 4-Ethyl-5,5-dimethylpentane
(a) Draw
a Newman
projection of the most stable conformation.
tion for
bromoethane.
(c) 3-Ethyl-4,4-dimethylhexane
(d) 5,5,6-Trimethyloctane
(b) Draw a Newman projection of the least stable conformation.
3.52 (e)
Increased
substitution
around
a
bond
leads to increased strain. Take the four
2-Isopropyl-4-methylheptane
→ CH3 eclipsing interaction
(c) If a CH3 ←
costs 11 kJ/mol (2.5 kcal/mol) and
butanes
for example.
sight
along
ng. All Rights Reserved. May not be copied,substituted
scanned, or duplicated,
in whole listed
or in part. below,
Due to electronic
rights, some thirdFor
partyeach
content compound,
may be suppressed from
the eBook
and/or eChapter(s).
←→ CH3 and
a
CH
gauche
interaction
costs
3.8
kJ/mol
(0.9 atkcal/mol),
make
a
3.41
Propose
structures
give
IUPAC
names
for
the
following:
3
y suppressed content does not materially affect
overall
learning
experience.
reserves the
right to remove additional
content
anystable
time if subsequent
rights restrictions require it.
thetheC2
–C3
bond
andCengage
drawLearning
Newman
projections
of the
most
and least
quantitative
plot of energy versus
about the C2–C3 bond.
(a) A
diethyldimethylhexane
(b) Arotation
(3-methylbutyl)-substituted
alkane
stable conformations. Use the data in Table 3.5 to assign strain energy values
3.43
What
areconformation.
the relative energies
staggered
conformations
to each
Which of
of the
the three
eight possible
conformations
is most
strained?
Conformations
TER 3 | Organic Compounds:
Alkanes and Their Stereochemistry
around
the
C2–C3
bond in 2,3-dimethylbutane? (See Problem 3.42.)
Which is
least
strained?
3.42 Consider 2-methylbutane (isopentane). Sighting along the C2–C3 bond:
(a) 2-Methylbutane
(b) 2,2-Dimethylbutane
Draw a Newman
projection
of the most diagram
stable conformation.
3.44 (a)
Construct
a qualitative
potential-energy
for rotation about the
General
(c) Problems
2,3-Dimethylbutane
(d) 2,2,3-Trimethylbutane
(b)
Draw
a Newman
projection of the
least stable
conformation.
C!C
bond
of 1,2-dibromoethane.
Which
conformation
would you expect
3.48 For each of the following compounds, draw an isomer that has the same
←→ CH
a CH
eclipsing
interaction
costs
11gauche
kJ/mol
(2.5
kcal/mol)
to
most
stable?
Label
the
andsuch
conformations
of
3.53 (c)
TheIfbe
cholesterol-lowering
agents
calledanti
statins,
as simvastatin
(Zocor)and
and
3
3
functional groups.
→(Pravachol),
a CH3 ←
CH3 gaucheare
interaction
costs
3.8 widely
kJ/mol prescribed
(0.9 kcal/mol),
a
1,2-dibromoethane.
pravastatin
among the
most
drugsmake
in the
CH3
(a)
(b)
(c) CH3CH2CH2C N
OCH3
quantitative
plotsales
of energy
versus
about
the
world,
with annual
estimated
at rotation
approximately
$15C2–C3
billion.bond.
Identify the
3.45 Which conformation of 1,2-dibromoethane (Problem 3.44) would you expect
CH3CHCHgroups
functional
2CH2Br in both, and tell how the two substances differ.
3.43 What
are the
of the threeThe
possible
staggered
conformations
to have
the relative
largest energies
dipole moment?
observed
dipole
moment of
Exercises
107
around
the C2–C3 bond
2,3-dimethylbutane?
(Seeyou
Problem
1,2-dibromoethane
is ! "in1.0
D. What does this tell
about 3.42.)
the actual con(d)
(e) CH3CH2CHO
CH2CO2H
(f)
OH
formation of the molecule?
3.44 Construct a qualitative potential-energy diagram for Orotation about the
! C bond
of 1,2-dibromoethane.
Which
conformation
would
you
expect
3.46 C
Draw
the
most
stable conformation
of pentane,
usingCwedges
and
dashes
to
HO
O
HOand
to
be most
stable?
Label
thethe
anti
and
gauche
conformations
of
represent
bonds
coming
out of
paper
goingOH
behind the paper,
1,2-dibromoethane.
respectively.
OH this compound
3.49 Malic
acid, C H O O
, has been isolated from apples. Because
4
6
105
105
5
O
O
reacts
2 molar
equivalents
of base,
it is (Problem
a dicarboxylic
3.45
conformation
of
1,2-dibromoethane
3.44) acid.
would
you expect
3.47 Which
Draw with
the
most
stable
conformation
of 1,4-dichlorobutane,
using wedges
and
(a)
Draw
least
five bonds
possible
structures.
to
have
the
largest
dipolecoming
moment?
The
dipole
of
dashes
toat
represent
out of
theobserved
paper and
goingmoment
behind the
O
O is its structure?
(b)
If malic
acid is aissecondary
what
1,2-dibromoethane
! " 1.0 D.alcohol,
What does
this tell you about the actual conpaper,
respectively.
CH3
CH3
of theHmolecule?
3.50 formation
Formaldehyde,
2C!O, is known to all biologists because of its usefulness as
a tissue
pure, formaldehyde
trimerizes
to and
give dashes
trioxane,
3.46 Draw
thepreservative.
most stable When
conformation
of pentane, using
wedges
to
C
surprisingly
enough,
has
no
carbonyl
groups.
Only
one
H3represent
C 3H6O3, which,
HO
bonds coming out of the paper and going behind the paper,
monobromo derivative (C3H5BrO3) of trioxane is possible. Propose a structure
respectively.
Simvastatin
Pravastatin
for trioxane.
(Zocor)
(Pravachol)
Copyright
2010
Cengage
Learning.
Rights
Reserved.
May
be copied,
or rights,
duplicated,
in
whole
or content
in part. Due
some
third
party content
may be suppressed from the eBook and/or eChapter(s).
ng. All Rights Reserved.
May
not3.47
be copied,
scanned,All
or duplicated,
instable
whole
ornot
in
part.
Due toscanned,
electronic
some
third
party
may to
beelectronic
suppressed
from
the eBook
and/or
eChapter(s).
Draw
the
most
conformation
of
1,4-dichlorobutane,
usingrights,
wedges
and
Editorialdoes
review
has3.51
deemedaffect
that
any
suppressed
content
does not Cengage
materially
affect the
overall
learning
experience.
Cengage
Learning any
reserves
the
right
remove
content at any time if subsequent rights restrictions require it.
The
barrier
toexperience.
rotation
about
the
Cout
"
C
bromoethane
15 tokJ/mol
y suppressed content
not materially
the overall
Learning
reserves
the
rightbond
additional
content
timeis
if subsequent
rightsadditional
dashes
tolearning
represent
bonds
coming
ofto remove
the in
paper
and atgoing
behind
therestrictions require it.
(3.6 kcal/mol).
paper,
respectively.
3.54 We’ll look
the next
chapter
at cycloalkanes—saturated
cyclic
carbons—
→ Br hydro
(a)inWhat
energy
value
can you assign to an H ←
eclipsing
interaction?
and we’ll(b)
seeConstruct
that the molecules
generally
adopt
confora quantitative
diagram
ofpuckered,
potential nonplanar
energy versus
bond rotamations. Cyclohexane,
for instance, has a puckered shape like a lounge chair
tion for bromoethane.
rather than a flat shape. Why?
3.52 Increased substitution around a bond leads to increased strain. Take the four
substitutedHbutanes listed
below, for example.
ForHeach compound, sight along
H
H
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).