Organic Chemistry
,
Suggested solutions for Chapter 2 2
PROB LE M 1
Draw good diagrams of saturated hydrocarbons with seven carbon atoms
having (a) linear, (b) branched, and (c) cyclic structures. Draw molecules based
on each framework having both ketone and carboxylic acid functional groups
in the same molecule.
Purpose of the problem
To get you drawing simple structures realistically and to steer you away
from rules and names towards more creative and helpful ways of
representing molecules.
Suggested solution
There is only one linear hydrocarbon but there are many branched and
cyclic options. We offer some possibilities, but you may have thought of
others.
linear saturated hydrocarbon (n-heptane)
some branched hydrocarbons
some cyclic hydrocarbons
We give you a few examples of keto-carboxylic acids based on these
structures. A ketone has to have a carbonyl group not at the end of a chain; a
carboxylic acid functional group by contrast has to be at the end of a chain.
You will notice that no carboxylic acid based on the first three cyclic
structures is possible without adding another carbon atom.
,2 Solutions Manual to accompany Organic Chemistry
linear molecules containing O
ketone and carboxylic acid CO2H
O CO2H
some branched keto-acids
CO2H O CO2H HO2C
HO2C
O
O O
some cyclic keto-acids
O O CO2H
CO2H
CO2H O
HO2C O
PROB LE M 2
Draw for yourself the structures of amoxicillin and Tamiflu shown on page 10
of the textbook. Identify on your diagrams the functional groups present in
each molecule and the ring sizes. Study the carbon framework: is there a single
carbon chain or more than one? Are they linear, branched, or cyclic?
NH2
H H H O
N S O
H3C O CH3
O N
HO O H3C HN
CO2H Tamiflu (oseltamivir):
NH2
SmithKline Beechamʼs amoxycillin H3C O invented by
β-lactam antibiotic Gilead Sciences;
for treatment of bacterial infections marketed by Roche
Purpose of the problem
To persuade you that functional groups are easy to identify even in
complicated structures: an ester is an ester no matter what company it keeps
and it can be helpful to look at the nature of the carbon framework too.
Suggested solution
The functional groups shouldn’t have given you any problem except perhaps
for the sulfide (or thioether) and the phenol (or alcohol). You should have
seen that both molecules have an amide as well as an amine.
, Solutions for Chapter 2 – Organic structures 3
amine NH2 ether O ester
H H H sulfide O
N S H3C O CH3
O N H3C HN
HO O
amide
phenol or amide NH2 amine
CO2H H3C O
alcohol carboxylic acid
amide
The ring sizes are easy and we hope you noticed that one bond between
the four- and the five-membered ring in the penicillin is shared by both
rings.
five- O
NH2
six-membered H H H membered O
N S H3C O CH3
O N H3C HN
HO O six-membered
NH2
four-membered CO2H H 3C O
The carbon chains are quite varied in length and style and are broken up
by N, O, and S atoms.
cyclic C3 O
cyclic C6 NH2 linear C5 linear C2
H H H O
N S H3C O CH3
O N H3C HN cyclic C6
HO O linear C2 NH2
linear C2 CO2H
branched C5
H3C O
,
Suggested solutions for Chapter 2 2
PROB LE M 1
Draw good diagrams of saturated hydrocarbons with seven carbon atoms
having (a) linear, (b) branched, and (c) cyclic structures. Draw molecules based
on each framework having both ketone and carboxylic acid functional groups
in the same molecule.
Purpose of the problem
To get you drawing simple structures realistically and to steer you away
from rules and names towards more creative and helpful ways of
representing molecules.
Suggested solution
There is only one linear hydrocarbon but there are many branched and
cyclic options. We offer some possibilities, but you may have thought of
others.
linear saturated hydrocarbon (n-heptane)
some branched hydrocarbons
some cyclic hydrocarbons
We give you a few examples of keto-carboxylic acids based on these
structures. A ketone has to have a carbonyl group not at the end of a chain; a
carboxylic acid functional group by contrast has to be at the end of a chain.
You will notice that no carboxylic acid based on the first three cyclic
structures is possible without adding another carbon atom.
,2 Solutions Manual to accompany Organic Chemistry
linear molecules containing O
ketone and carboxylic acid CO2H
O CO2H
some branched keto-acids
CO2H O CO2H HO2C
HO2C
O
O O
some cyclic keto-acids
O O CO2H
CO2H
CO2H O
HO2C O
PROB LE M 2
Draw for yourself the structures of amoxicillin and Tamiflu shown on page 10
of the textbook. Identify on your diagrams the functional groups present in
each molecule and the ring sizes. Study the carbon framework: is there a single
carbon chain or more than one? Are they linear, branched, or cyclic?
NH2
H H H O
N S O
H3C O CH3
O N
HO O H3C HN
CO2H Tamiflu (oseltamivir):
NH2
SmithKline Beechamʼs amoxycillin H3C O invented by
β-lactam antibiotic Gilead Sciences;
for treatment of bacterial infections marketed by Roche
Purpose of the problem
To persuade you that functional groups are easy to identify even in
complicated structures: an ester is an ester no matter what company it keeps
and it can be helpful to look at the nature of the carbon framework too.
Suggested solution
The functional groups shouldn’t have given you any problem except perhaps
for the sulfide (or thioether) and the phenol (or alcohol). You should have
seen that both molecules have an amide as well as an amine.
, Solutions for Chapter 2 – Organic structures 3
amine NH2 ether O ester
H H H sulfide O
N S H3C O CH3
O N H3C HN
HO O
amide
phenol or amide NH2 amine
CO2H H3C O
alcohol carboxylic acid
amide
The ring sizes are easy and we hope you noticed that one bond between
the four- and the five-membered ring in the penicillin is shared by both
rings.
five- O
NH2
six-membered H H H membered O
N S H3C O CH3
O N H3C HN
HO O six-membered
NH2
four-membered CO2H H 3C O
The carbon chains are quite varied in length and style and are broken up
by N, O, and S atoms.
cyclic C3 O
cyclic C6 NH2 linear C5 linear C2
H H H O
N S H3C O CH3
O N H3C HN cyclic C6
HO O linear C2 NH2
linear C2 CO2H
branched C5
H3C O
