Transcript Part 2 - Class Index

Functional Groups: “reactive” centers that contain heteroatoms or multiple carbon-carbon
bonds.
H
H
H
H
H
C
C
N
C
O
H
H
Br
C
H
Heteroatom: atoms other than carbon or hydrogen. Typically N, O, Si, P, S, Se, F, Cl, Br, I.
multiple carbon-carbon bonds: unsaturation.
H H
H
H
H H
C
H
C
H
C
C
C
H
H H
H H
alkanes
H
H
H
C
H
H
C
C
C
H
H
H
alkenes
C
C
C
H
H
alkynes
H
The Functional Groups
(Table 1.1 page 4)
Structure
Condensed Structure
O
CO2H or
C
H
O
O
Name
Carboxylic acid
Nomenclature suffix
-oic acid
COOH
O
S
H
O
SO3H
Sulfonic acid
-sulfonic acid
O
C
R
O
CO2R or
COOR
Ester
-oate
O
COCl
C
Acid chloride
-oyl chloride
Cl
O
C
H(R)
CONH2(R) 2
N
Amide
-amide
H(R)
C
N
CN
Nitrile
-nitrile
O
C
CHO
Aldehyde
-al
H
O
C
CO
Ketone
-one
Alcohol
-ol
O
H
OH
S
H
SH
Thiol
NH2
Amine
-amine
Alkene
-ene
-thiol
H
N
H
C
C
C
Alkyne
C
O
O
Ether
-yne
N/A
H
H
C
C
H
C
C
C
C
Arene
N/A
Phenol
N/A
H
H
H
H
C
C
H
C
C
C
C
O
O
H
H
H
H
other common functional groups…
S
Sulfide
S
S
S2
Disulfide
SO
Sulfoxide
O
S
O
NO2
N
O
Nitro
Things to watch for...
…common structural elements.
OH
O
C
OH
O
C
H
N
H
O
C
IMPORTANT: the carbonyl group by itself is not a functional group. It is part of
many functional groups depending on what is attached to it.
Organic Nomenclature Summary (from Chem2000:
CH3O
CH3O
5
In summary, to name an organic molecule, work back-to-front:
– Find the principal functional group.
O
Br
– Find the longest chain (or ring) including the principal functional group
and all double/triple bonds.
Br
– Number the chain starting at whichever end gives the principal functional
O
Br
group the lower number. (For a ring, start numbering at the principal
functional group.)
2
4
3
1
– Name the principal functional group, numbering if necessary.
Br
-2-one
–
–
–
Name the main chain (or ring), numbering the C=C or CC bonds if
necessary. If this gives a name in which the next letter after the ‘e’ of
‘ane’, ‘ene’ or ‘yne’ is a vowel, drop the ‘e’.
-3-penten-2-one
Name and number the substituents on the main chain. If a substituent
appears more than once, use a prefix to indicate how many there are and
include a number for each appearance. List the substituents in
alphabetical order (not counting prefixes) followed by the main chain (or
ring) name.
3,4-dibromo-5-methoxy-3-penten-2-one
Finally, add cis- or trans- to the front of the name if necessary.
trans-3,4-dibromo-5-methoxy-3-penten-2-one
Organic Nomenclature
Systematic IUPAC Nomenclature – Compound names have four fields.
First field
Second field
Third field
Fourth field
substituents
compound root
saturation index
principal functional group
•The first field includes the names and positions of substituents.
•The second field contains the compound root word (longest carbon chain).
•The third field indicated the saturation index (single or multiple bonds).
•The fourth field defines the principal functional group (drop the terminal ‘e’ from the
saturation index and add the appropriate suffix).
Compound Root – Second Field
the compound root name is based on the number of carbon atoms in the longest continuous
chain or ring.
n
1
2
3
4
5
6
7
8
9
10
CnH2n+2
CH4
CH3CH3
CH3CH2CH3
CH3(CH2)2CH3
CH3(CH2)3CH3
CH3(CH2)4CH3
CH3(CH2)5CH3
CH3(CH2)6CH3
CH3(CH2)7CH3
CH3(CH2)8CH3
alkane
meth-ane
eth-ane
prop-ane
but-ane
pent-ane
hex-ane
hept-ane
oct-ane
non-ane
dec-ane
For cyclic molecules, the prefix
‘cyclo’ is added before the
compound root prefix.
Saturation Index – Third Field
The presence of multiple bonds is indicated by “ene” (carbon-carbon double bonds) and/or
“yne” (carbon-carbon triple bonds) in the third field of the name
•hexane
•1-hexene (or hex-1-ene)
•1-hexyne (or hex-1-yne)
When a principal functional group is not present, number the chain to give the multiple bond the
lowest number. If there are multiple multiple bonds, add the prefix di, tri, tetra, etc to indicate
the number of double or triples bonds in the molecule and give a number to indicate its position.
•1,3-hexadiene (or hexa-1,3-diene)
•1,5-hexadiene (or hexa-1,5-diene)
•1-hexen-3-yne (or hex-1-en-3-yne)
•1-hexen-5-yne (or hex-1-en-5-yne)
Substituents – First Field
Substituents are structural elements (often functional groups) that are not part of the
longest chain, but attached to it. Substituents appear first in a name and are
numbered with respect to their position. Substituents take last priority when
numbering the main chain. Substituents are listed alphabetically and their location
indicated by a number. Multiples of the same substituent are numbered and
indicated by a prefix (di, tri, tetra, penta, etc).
•5-chloro-1-hexene (or 5-chlorohex-1-ene)
•4,5-dichloro-5-fluoro-1-hexene (or 4,5-dichloro-5-fluorohex-1-ene)
Principal Functional Groups – Forth Field
A Principal Functional Group will always take priority when numbering the main
chain (followed by multiple bonds followed by substituents). The following table
lists the Principal Functional Groups that you are responsible for in Chem 2500.
They are listed in order of highest priority down to lowest priority.
Functional Group
Suffix
Carboxylic acid
-oic acid
Sulfonic acid
-sulfonic acid
Ester*
-oate
Acid Chloride
-oyl chloride
Amide*
-amide
Nitrile
-nitrile
Aldehyde
-al
Ketone
-one
Alcohol (including phenol)
-ol
Thiol
-thiol
Amine
-amine
Note that certain functional groups are never considered as a principal functional group
and are always treated as a substituent. These include the halogens, ethers, and nitro
groups.
Principal Functional Groups – Forth Field
There can only be one Principal Functional Group in a molecule. The functional
group with the highest priority according to the previous table is named as the
principal functional group and all others are named as substituents.
•5-chloro-1-hexen-3-ol (or 5-chlorohex-1-en-3-ol)
•2-chloro-5-hexen-1-ol (or 2-chlorohex-5-en-1-ol)
•2-chloro-4-hydroxy-5-hexenal (or 2-chloro-4-hydroxyhex-5-enal)
Note that no number is necessary for principal functional groups that must be
terminal because they include the first carbon atom of the main chain.
Substituent List
Below is a list of all substituents that you are responsible for in Chem 2500. Some
substituents listed are functional groups that were lower in priority than the
principal functional group.
Name
Name
Name
-CH3
methyl
-OCH3
methoxy
-F
fluoro
-CH2CH3
ethyl
-OCH2CH3
ethoxy
-Cl
chloro
-CH2CH2CH3
propyl
-OCH2CH2CH3
propoxy
-Br
bromo
-CH2CH2CH2CH3
butyl
-OCH2CH2CH2CH3
butoxy
-I
iodo
-NH2
amino
etc.
etc.
-CH(CH3)2
isopropyl
-OCH(CH3)2
isopropoxy
-NO2
nitro
-CH2CH(CH3)2
isobutyl
-OCH2CH(CH3)2
isobutoxy
-CN
cyano
CH(CH3)CH2CH3
s-butyl
OCH(CH3)CH2CH3
s-butoxy
-C(CH3)3
t-butyl
-OC(CH3)3
t-butoxy
-OH
hydroxy
-C6H5
phenyl
-OC6H5
phenoxy
=O
oxo
-CH2C6H5
benzyl
-OCH2C6H5
benzoxy
-SH
mercapto
Other names you need to know...
H
H
C
H
C
C
C
C
=
Benzene
H
C
H
H
Molecules with this substructure are treated as a class – arenes.
CH3
toluene*
NH2
aniline*
OH
phenol
CHO
CO2H
benzaldehyde
benzoic acid
*these are not IUPAC names but common names that you should know.
Naming Carbon-Based Substituents
H
H
C
H
C
H
H
H
H
C
H
H
H
C
C
H
H
ethane
methyl group
methyl
methane
H
H
H
C
H
H
ethyl
H
ethyl group
H H
H
C
C
H
H H
H
C
H
H
H
The n-propyl or propyl
group. ("n" stands for
normal i.e. straight chain)
H H
n-propyl
H
C
C
C
H H
H
propane
H
H
C
C
H
H
C
H H
The 2-propyl or isopropyl
group.
isopropyl
Notice that the only difference between n-propyl and isopropyl is the point of attachment.
H
H
HH
C
C
H
H
H
H
HH
C
C
C
C
H H
H H
The n-butyl or butyl group.
n-butyl
H
C
C
H H
H H
butane
H
H
H
H
H
C
C
C
C
H H
H H
sec-butyl
Again, notice that the only difference is the point of attachment.
The 2-butyl, sec-butyl
or s-butyl group.
H2C
C
H3C
H3C
H3C
isobutyl
C
H
The isobutyl group.
H
H3C
H 3C
isobutane
H3C
C
H 3C
H 3C
tert-butyl
The 2-methyl-2-propyl,
tert-butyl or t-butyl group.
Aryl based Substituents
Phenyl
Ph
or –C6H5
not to be confused with ‘phenol’
H2
C
Benzyl
“benzylic”
Bn
or –CH2C6H5
Name the following molecules