Organic ChemistryOrganic Chemistry

a branch of chemistry concerned a branch of chemistry concerned with the study of carbon and its with the study of carbon and its compounds.compounds.

HydrocarbonsHydrocarbons

the simplest class of organic the simplest class of organic compounds containing carbon & compounds containing carbon & hydrogen onlyhydrogen only

hydrocarbons

aromaticaliphatic

alkanes cycloalkanes alkenes alkynes

Aliphatic Aliphatic HydrocarbonsHydrocarbons

A hydrocarbon with no aromatic ring

Example:CH31

CH2

CH3

CH34

CH3

CH3

Aromatic Aromatic HydrocarbonsHydrocarbons

a hydrocarbon containing one or more rings with delocalized electron systems

(example is benzene, C6H6) CH

CH

CH

CH

CH

CH

AlkanesAlkanes

are saturated hydrocarbons general formula is Cgeneral formula is CnnHH2n+2 2n+2

ex: CHex: CH4 4 (methane)(methane) single covalent bonds (C-C) between single covalent bonds (C-C) between

carbon to carbon molecules are carbon to carbon molecules are presentpresent

uses the –ane ending in its nameuses the –ane ending in its name

AlkanesAlkanes

The first 10 alkanes are named as follows:

CHCH44 methanemethaneCC66HH1414 hexanehexane

CC22HH66ethaneethane CC77HH1616 heptaneheptane

CC33HH88propanepropane CC88HH1818 octaneoctane

CC44HH1010 butanebutane CC99HH2020 nonanenonane

CC55HH1212 pentanepentane CC1010HH2222 decanedecane

CycloalkanesCycloalkanes

  alkanes whose carbon atoms are alkanes whose carbon atoms are joined in ringsjoined in rings

  general formula is Cgeneral formula is CnnHH2n2n

ex: C6H12 (cyclohexane)

uses the prefix cyclo and –ane ending in its name

CH2

CH2

CH2

CH2

CH2

CH2

Alkenes (Olefins)Alkenes (Olefins)

unsaturated hydrocarbons that unsaturated hydrocarbons that contain C=Ccontain C=C

general formula is Cgeneral formula is CnnHH2n2n (same as (same as

cyloalkane)cyloalkane) ex:Cex:C22HH44 (ethene) (ethene) uses the –ene ending in its nameuses the –ene ending in its name

CH2 CH2

Alkynes (Paraffins)Alkynes (Paraffins)

unsaturated hydrocarbons that unsaturated hydrocarbons that contain Ccontain CCC

general formula is Cgeneral formula is CnnHH2n-22n-2

ex: C2H2 (ethyne)

uses the –yne ending in its nameuses the –yne ending in its name

CH CH

Important NotesImportant Notes

an alkane less one hydrogen atom an alkane less one hydrogen atom is called an is called an alkyl groupalkyl group (example (example is when a hydrogen atom is is when a hydrogen atom is removed from methane, it is called removed from methane, it is called methylmethyl, -CH, -CH33))

Naming AlkanesNaming Alkanes

Step 1:Step 1: Determine the parent name by Determine the parent name by

finding the longest continuous chain finding the longest continuous chain of carbon atoms in the molecule. The of carbon atoms in the molecule. The parent name is the name of the parent name is the name of the alkane corresponding to the longest alkane corresponding to the longest continuous carbon chain. The longest continuous carbon chain. The longest chain may not be always written chain may not be always written horizontally.horizontally.

Naming AlkanesNaming Alkanes

CH31

CH22

CH23

CH24

CH25

CH36

hexane

CH36

CH25 CH2

4

CH3 CH3

CH22

CH31

3 – methylhexane3 – methylhexane

Naming AlkanesNaming Alkanes

If the molecule contains two chains If the molecule contains two chains of equal length, choose the one of equal length, choose the one with the greater number of with the greater number of substituents as the parent chain.substituents as the parent chain.

CH31

CH2

CH3

CH3

CH2 CH3

CH24

CH25

CH26

CH37

Naming AlkanesNaming Alkanes

  Step 2Step 2 name each substituent and precede name each substituent and precede

this name with the number of this name with the number of carbon atom on the parent chain to carbon atom on the parent chain to which it is bonded.which it is bonded.

Naming AlkanesNaming Alkanes

   Parent: butane Substituent: methyl Location: C2- methyl Name: 2 – methylbutane

CH31

CH2

CH23

CH34

CH3

Naming AlkanesNaming Alkanes

Two or more identical substituents present in a molecule are indicated by the use of the prefixes di for 2, tri for 3 tetra for 4, etc. Each of the identical substituents must have a number

Naming AlkanesNaming Alkanes

Parent: butane Substituent: methyl Location: C2 and C3- methyl Name: 2,3 –dimethylbutane

CH31

CH2

CH3

CH34

CH3

CH3

Naming AlkanesNaming Alkanes

When two or more substituents are present, their names are listed in alphabetical order

Naming AlkanesNaming Alkanes

 

Parent: heptane Substituent: methyl and ethyl Location: C2- methyl and C3- ethyl Name: 3 – ethyl – 2 – methylheptane Note: the name of the compound is

written in single word.

CH31

CH2

CH3

CH3

CH2 CH3

CH24

CH25

CH26

CH37

Naming Alkenes & Naming Alkenes & AlkynesAlkynes

Step 1: Choose the longest continuous carbon

chain that contains the double/triple bond as the parent chain.

Step 2: Number the chain to give the lowest

number to the first carbon of the double/triple bond.

Naming Alkenes & Naming Alkenes & AlkynesAlkynes

Step 3: Substitute the ending -ene for ending –ane

in the name of the corresponding alkane to obtain the parent alkene name and substitute –yne to obtain the parent alkyne. The position of the double/triple bond is indicated by a number.

Step 4: Write the complete name of the compound

with the correct number of all substituents, which are listed in alphabetical order.

ExamplesExamples

Parent: octene Location: C3 Substituent: methyl, ethyl & bromo Location: C3,C6- methyl; C4 bromo; C6-ethyl Name:4-Bromo–6-ethyl-3,6-dimethyl-3-

octene

CH22

C3

C4

Br

CH31

CH25

C6

CH2

CH27

CH38

CH3

CH3CH3

ExamplesExamples

Parent: butyne Location: C1 Substituent: methyl Location: C3 Name: 3 – methyl – 1- butyne

or 3- methylbutyne

CH3

C2

CH1

CH3

CH34

Aromatics: BenzeneAromatics: Benzene

Monosubstituted benzenes are named by combining the substituent name w/ the word benzene.

Name: 1 - ethylbenzene

C1

CH2

CH6

CH3

CH5

CH4

CH2 CH3

For disubstituted benzenes the 3 possible isomers are named using the prefixes ortho (o), meta (m) & para (p) to designate the 1,2 – 1,3 & 1,4 –relationships of sustituents on the benzene ring:

Name: 1,3-Dibromobenzene or meta-Dibromobenzene

CH2

C3

C1

CH4

CH6

CH5

Br

Br

Exercises:Exercises:

Draw the structure of the following hydrocarbons:

1. 2,2-dimethylpentane2. 4-ethyl-2,3-dimethyloctane3. 3-ethyl-3-methyl-1-pentene4. 1,3- dibromobenzene

Exercises:Exercises:

Give the name of the following Hydrocarbons:

1.

2.

CH3

C C CH

CH3

CH2 CH3

CH3 CH

CH3

C

CH2

CH3

CH

CH2 CH

CH3

CH2 CH3

3. 4.

5. 6.

CH

CH

CH

C

C

CH

CH3

CH3

Cl

Br

Br

CH2 C

CH3

CH C CH CH3

CH CH3

CH3

Cl CH2

CH2

CH

CH2

CH3

Hydrocarbon Hydrocarbon DerivativesDerivatives

these are compounds that are formed when one, two or three hydrogen atoms in the hydrocarbon molecules are replaced by atoms or group of atoms that are responsible for the properties of that compound. This group of atoms is called the functional group.

ALCOHOLS

Contains the –OH group (hydroxyl)ex:

CH3-OH methanol

CH3CH2-OH ethanol

phenol

OH

Some Typical Alcohols OH “rubbing alcohol” CH3CHCH3

2-propanol (isopropyl alcohol)

antifreeze HO-CH2-CH2-OH

1,2-ethanediol (ethylene glycol)

OH

glycerol HO-CH2-CH-CH2OH

Ant

i-fre

eze

Ethers

Contain an -O- between two carbon groups

CH3-O-CH3 dimethyl ether

CH3-O-CH2CH3 ethyl methyl

ether

Aldehydes and Ketones

In an aldehyde, an H atom is attached to a carbonyl group

O carbonyl group CH3-C-HIn a ketone, two carbon groups are

attached to a carbonyl group

O carbonyl group CH3-C-CH3

Aldehydes as Flavorings

Benzaldehyde Vanillin Cinnamaldehyde(almonds) (vanilla beans) (cinnamon)

CH=CH CH

OCH

O

HO

OCH3

CH

O

Ketones

O O

Butter flavor CH3-C-C-CH3

butanedione

propanone

CH3

C

CH3

O

acetone

Amines

Organic compounds of nitrogen N Classified as primary, secondary, tertiary

CH3 CH3

CH3—NH2 CH3—NH CH3—N — CH3

1° 2° 3°

Alkaloids

Physiologically active nitrogen-containing compounds

Obtained from plants Used as anesthetics, antidepressants, and

stimulants Many are addictive

Some Common Amines

N

CH3

Nicotine, leaves of tobacco plant

N

N N

NCH3

O

O CH3

CH3

Caffeine, coffee beans and tea

Some Common Amines

NH2N

CH3CH2

CH3CH2

CH2CH2 O C

O

Procaine (novocaine), painkiller

Carboxylic Acid

Carboxylic acids contain the carboxyl group on carbon 1.

O

CH3 — C—OH CH3—COOH

carboxyl group

Some Carboxylic Acids & their Names

OH C CH2 C CH2

O

OH

C C OH

OO

OH

2-hydroxypropane-1,2,3-tricarboxylic acid

Citric acid COH

O

OC

CH3

O

2-(acetyloxy)benzoic acid

Aspirin

Amides

Derivatives of carboxylic acids where an amino (-NH2) group replaces the –OH group.

O O CH3 — C—OH CH3 — C—NH2

carboxylic acid amide

acetic acid acetamide

Some Amides & their Names

O

CH3C–NHCH3 N-methylethanamide

(IUPAC)N-methylacetamide

(common)C

O

NH2

Benzamide

C

O

NHCH3

N methylbenzamide -

Esters

In an ester, the H in the carboxyl group is replaced with an alkyl group

O

CH3 — C—O —CH3 CH3—COO —CH3

ester group

Esters in Plants

Esters give flowers and fruits their pleasant fragrances and flavors.

Some Esters and Their Names

Flavor/OdorRaspberries

HCOOCH2CH3 ethyl methanoate (IUPAC)

ethyl formate (common)

Pineapples

CH3CH2CH2 COOCH2CH3

ethyl butanoate (IUPAC)

ethyl butyrate (common)

Exercises:

Identify the functional groups present in the following compounds:

O

OH

CH3 CH2

CH2 NH

CH3

CH2

CH

OH

CH3

CH3

H C

CH

O

CH3

CH3

(1)

(2)

(4)

(3)

CH3 C

O

NH

CH3

CH3 C

O

CH

CH3

CH3

CH3 CH

CH3

O CH3

CH3 C

O

O

(5)

(8)

(7)

(6)