Organic Chemistry Organic chemistry is the chemistry of the carbon atom. It is the chemistry of all life on earth. Carbon atoms bond to other atoms of.

Organic Chemistry

Organic Chemistry Organic chemistry is the chemistry of the carbon

atom. It is the chemistry of all life on earth. Carbon atoms bond to other atoms of

carbon hydrogen and sometimes oxygen, nitrogen, sulfur and

phosphorus A few compounds contain carbon but are not

considered to be organic: CO2, CO, H2CO3, CaCO3

Hydrocarbons Hydrocarbons are the simplest organic molecules. They are made of only carbon C and hydrogen H

atoms Each carbon atom makes 4 bonds Each hydrogen atom makes 1 bond -H If each carbon makes only one bond to each of its

neighbours, it is called an ‘alkane’

Systematic NomenclatureSystematic NomenclatureInternational Union of Pure and Applied

Chemistry (IUPAC)Committee on Organic Nomenclature

# C #C

1 meth- 6 hex-

2 eth- 7 hept-

3 prop- 8 oct-

4 but- 9 non-

5 pent- 10 dec-

Methane (CH4) CH4

Ethane (C2H6) CH3CH3

Propane (C3H8) CH3CH2CH3

bp -160°Cbp -160°C bp -89°Cbp -89°C bp -42°Cbp -42°C

The Simplest Alkaneshave only C and H, only single bonds, and all names end in ‘ane’

CHCH33CHCH22CHCH22CHCH22CHCH22CHCH33

PentanePentane

HexaneHexane

CHCH33CHCH22CHCH22CHCH22CHCH33

CHCH33CHCH22CHCH22CHCH22CHCH22CHCH22CHCH33

HeptaneHeptane

ButaneButane

CHCH33CHCH22CHCH22CHCH33

The alkanes The alkanes

Methane (CH4)

Ethane (C2H6)

Propane (C3H8)

Butane (C4H10)

Pentane (C5H12)

Hexane (C6H14)

Heptane (C7H16)

Octane (C8H18)

Nonane (C9H20)

Decane (C10H22)

CH4

CH3 CH3

CH3 CH2 CH3

CH3 CH2 CH2 CH3

CH3 CH2 CH2 CH2 CH3

CH3 CH2 CH2 CH2 CH2 CH3

CH3 CH2 CH2 CH2 CH2 CH2 CH3

CH3 CH2 CH2 CH2 CH2 CH2 CH2 CH3

CH3 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH3

CH3 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH2 CH3

Nomenclature of the AlkanesNomenclature of the Alkanes

Alkanes always have the ending -ane.Side chains (substituents) are named as

alkyl groups.

Common alkyl groupsCommon alkyl groups (C (C11 through C through C44))

CH3

CH3 CH2

CH3 CH2 CH2

CH3 CH2 CH2 CH2

Methyl

Ethyl

Propyl

Butyl

Isopropyl

Isobutyl

(1-Methylethyl)

(2-Methylpropyl)

sec-Butyl

(1-Methylpropyl)

tert-Butyl

(1,1-Dimethylethyl)

CH3 CH

CH3

CH3 CH CH2

CH3

CH3 CH2 CH

CH3

CH3 C

CH3

CH3

IUPAC nomenclature of alkanesIUPAC nomenclature of alkanes

1. identify the longest chain -- parent

2. number from the end closest to first branch

3. Name the groups attached to the chain, using the carbon number as the locator.

4. Alphabetize substituents.

5. Use di-, tri-, etc., for multiples of same substituent

6. combine number and name of substituent with parent name, separating with hyphen

Longest Chain The number of carbons in the longest chain

determines the base name: ethane, hexane. If there are two possible chains with the

same number of carbons, use the chain with the most branches (substituents).

C

CH3

CH2

CH3

CH CH2 CH2 CH3

CH CH2 CH3H3C

H3C

=>

Number the Carbons

Start at the end closest to the first attached group.

If two substituents are equidistant, look for the next closest group.

1

2

3 4 5

6 7CHH3C

CH3

CH

CH2CH3

CH2 CH2 CH

CH3

CH3

CH3 CH2 CH CH3

CH3

Organic nomenclatureOrganic nomenclature

4 3 2 1

2-methylbutane

Naming Branched Alkanesaddress # - branch name + yl+ parent name

2-methylpropane

CH3 CH2 CH CH3

CH2 CH3

Find the longest continuousFind the longest continuouscarbon chaincarbon chain

1 2 3

4 5

3-methylpentane

CH3 CH2 CH CH2 CH2 CH3

CH2 CH2 CH3

You must choose the longestYou must choose the longestcontinuous carbon chaincontinuous carbon chain

4 3 2 1

5 6 7

4-ethylheptane

CH3 CH2 CH2 CH CH CH2 CH3

CH3

CH2 CH3

Number from the end nearestNumber from the end nearestthe first substituentthe first substituent

7 6 5 4 3 2 1

4-ethyl-3-methylheptane

CH3 CH2 CH2 CH CH2 CH CH2 CH3

CH2 CH3

CH3

Number from the end nearestNumber from the end nearestthe first substituentthe first substituent

8 7 6 5 4 3 2 1

3-ethyl-5-methyloctane

CH3 CH CH CH3

CH3

CH3

Use “di-” with two substituentsUse “di-” with two substituents

1 2 3 4

2,3-dimethylbutane

CH3 CH2 C CH2 CH2 CH3

CH3

CH3

Every substituent must get a numberEvery substituent must get a number

1 2 3 4 5 6

3,3-dimethylhexane

CH3 CH2 CH CH CH2 CH2 CH2 CH2 CH CH3

CH3CH3

CH3

Number from the end nearestNumber from the end nearestfirst substituentfirst substituent

10 9 8 7 6 5 4 3 2 1

2,7,8-trimethyldecane

CH3 CH2 CH CH CH2 CH2 CH2 CH CH2 CH3

CH3

CH3

CH3

Number from the end which hasNumber from the end which hasthe “first difference”the “first difference”

1 2 3 4 5 6 7 8 9 10

3,4,8-trimethyldecane

CH3 CH CH2 C CH3

CH3 CH3

CH3

A More-Highly-SubstitutedA More-Highly-SubstitutedCarbon Takes PrecedenceCarbon Takes Precedence

5 4 3 2 1

2,2,4-Trimethylpentane

CH3 CH2 CH CH2 CH2 CH CH2 CH3

CH3 CH2 CH3

Which end do we number from?Which end do we number from?

8 7 6 5 4 3 2 1

3-ethyl-6-methyloctane

IUPAC rules

1. Find the longest straight chain = parent chain

2. Number the parent chain in the direction that gives the lowest number to the substituents at the first point of difference.

3. Two or more identical groups are indicated by di, tri, tetra, etc.

CH3 CH2 CH2 CH2 CH

CH2 CH3

CH3Longest chain is 7 (not 6).This is 3-methylheptane.

.

2,3,6-trimethylheptane (not 2,5,6-trimethyl heptane)

2,2,6,6,7-pentamethyloctane (not 2,3,3,7,7-pentamethyloctane)

4. Different groups are listed in alphabetical order (di, tri, tetra, etc. don’t count).

5. If the numbering is the same in both directions, choose the numbering to follow the alphabetical order.

IUPAC rules

6-ethyl-2,2-dimethyloctane

5-ethyl-6-methyldecane

6. When two or more chains compete for the longest, the choice goes to the one with the greater number of side groups.

IUPAC rules

2,4,6-trimethyl-5-propyloctane

IUPAC rules

6-ethyl-2,2,5,7-tetramethylnonane (not 6,7-diethyl-2,2,5-trimethyloctane.

Name the following compounds.

CH2CH2

CH2CH

CH2CH3 C

CH2CH2

CH2CH2

CH2CH3

CH3

CCH3 CH2

CH3 CH2 CH3

CH3

Good Luck!Good Luck!

7-(1,1-Dimethylbutyl)-3-ethyl-7-methyldodecane

Halogens and other side groups Flouro –F Chloro –Cl Bromo –Br Iodo –I Nitro –NO2 N

O

O

CH3 CH2 Br

Bromoethane

“Ethyl bromide”

CH3 C Cl

CH3

CH3

2-Chloro-2-methylpropane

CH3 CH CH CH2 CH3

Br CH3

2-Bromo-3-methylpentane

Common Nomenclature Common Nomenclature PitfallsPitfalls

Did not find the longest carbon chainNumbered chain from the wrong endForgot to repeat number for each identical

substituent; forgot to use di- tri- tetra-, etc.Writing the name as more than one wordIncorrect punctuation

cyclic moleculescyclic molecules

CC

C

H H

H

H

H

H

CH2

CH2

CH2

Cyclopropane

C

C C

C

H

H

H

H

H

H

H

H

CH2

CH2 CH2

CH2

Cyclobutane

C

C

C

C

C

H HH H

HH

HH

HH

CH2

CH2

CH2

CH2

CH2

Cyclopentane

C

CC

C

CC

H HH

H

H

H

HH

H

H

H

HCH2

CH2

CH2

CH2

CH2

CH2

Cyclohexane

Nomenclature for Cyclic Alkanes For compounds with a single ring, add the

prefix “cyclo-” to the root name for the alkane comprising the ring.

Nomenclature of the Substituted Nomenclature of the Substituted CycloalkanesCycloalkanes

If there is only one substituent, do not use the “1”. If there is more than one substituent, you must use all

numbers, including “1”! Number around the ring in a direction to get from the

first substituent to the second substituent by the shorter path.

For equivalent degrees of substitution, number in a direction that follows the alphabetical sequence.

A carbon with greater substitution has precedence in numbering.

Br

Bromocyclopropane

CH3

CH3

1,1-Dimethylcyclohexane

CH3

CH3

CH2CH3

4-Ethyl-1,1-dimethylcyclohexane

Numbering Starts at the Most Numbering Starts at the Most Highly-Substituted CarbonHighly-Substituted Carbon

Cl CH3

CH3

CH3

2 13 74 6 5

2-Chloro-1,1,6-trimethylcycloheptane

cycloalkyl groupscycloalkyl groups

Cyclopropyl Cyclobutyl

Cyclopentyl Cyclohexyl

C

CH3

CH2CH2CH3 CH3

3-Cyclobutyl-3-methylpentane

CH3 CH2 CH CH3

2-Cyclobutylbutane

Name the following cycloalkanes.

IUPAC rules

1,1,2-trimethycyclohexane