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Overview Lecture:

Carboxylic Acids, Esters, Amines

& Amides

Last Lecture Overview 1

Carboxylic Acids

O have the structure R-C-O-H , also written as:

RCOOH and RCO

2

H.

-COOH is called the carboxyl group.

Last Lecture Overview 2

Nomenclature of RCOOH

:

1. Find the longest chain that includes COOH.

2. Parent name becomes alkane + oic acid.

3. C of COOH becomes #1.

4. COOH more important than other functional groups.

Last Lecture Overview 3

Example

3

O

CH

3

-CH

2

-CH-CH

5 4

OH

2

2

-COH

1

3-hydroxy pentanoic acid

Last Lecture Overview 4

Carboxylic Acids are weak acids:

They are H

+ donors, but not completely ionized in water.

H-A H

+

+ A

K a

<< 1, which means that

At equilibrium mostly HA present.

Last Lecture Overview 5

Amines are organic bases derived from ammonia (NH

3

).

In amines a carbon group replaces an H in NH

3

.

Last Lecture Overview 6

Ammonia = H-N-H

H

R -NH

2

1

°

Amine

R -NH-

R’

2

°

Amine

Last Lecture Overview

R -NR

R

3

°

Amine

7

Simple Naming of Amines

Name the alkyl groups bonded to

N, followed by the word “amine” :

CH

3

CH

2

-NH-CH

3 is named ethyl methyl amine

Last Lecture Overview 8

Amines

* are Hydrogen-bond donors and

H-bond acceptors

* are weak bases

Last Lecture Overview 9

Amines

H

+ are bases acceptors.

because they are

All amines are weak bases like NH

3

.

R-NH

2

+ H

2

O R-NH

3

+

+ HO

-

K << 1

Last Lecture Overview 10

Esters and Amides are obtained by replacing the OH group of RCOOH.

O

R-COH

O

R-C-

OR’

Ester

O

R-CN

Amide

R’

R”

Last Lecture Overview 11

The OH of RCOOH can be replaced chemically in several steps in the lab or by enzymes.

More important than how:

1) Esters come from RCOOH + ROH

(an alcohol); while

2) Amides come from RCOOH +

Amine or Ammonia.

Last Lecture Overview 12

Example of Ester Synthesis

CH

3

CH

2

O

C OH

CH

3

+ H O-CH

2

CHCH

3

- H

2

O by enzyme or in lab

O CH

3

CH

3

CH

2

C O-CH

2

CHCH

3

Last Lecture Overview 13

Thus, the basic equation is

Carboxylic acid + alcohol

ester + water

Last Lecture Overview 14

Example of Amide Synthesis

O

CH

3

CH

2

C OH + H NH-CH

3

- H

2

O by enzyme or in lab

O

CH

3

CH

2

C NH-CH

3

Last Lecture Overview 15

Again, the basic equation is

Carboxylic acid + amine or NH

3 amide + water

Last Lecture Overview 16

Esters and Amides are hydrolyzed

(broken down by H

2

O in H

+ or HO

-

).

Ester + H

2

O

Carboxylic acid + Alcohol

Amide + H

2

O

Carboxylic acid + Amine

(or ammonia)

Last Lecture Overview 17

O

Hydrolysis Examples

O

Ester

C-OCH

2

CH

2

CH

3

H

2

O with enzyme or H

+ or HO

-

COH + HOCH

2

CH

2

CH

3 carboxylic acid alcohol

Last Lecture Overview 18

Hydrolysis Example 2

O

CH

3

C-NH-

Amide

H

2

O with enzyme or H

+ or HO

-

O

CH

3

C-OH + H

2

Ncarboxylic acid amine

Last Lecture Overview 19

That’s All Folks

The End

Last Lecture Overview 20

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