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7/23/2019 OC1 Chapter 4 Nomenclature (1)
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Chapter 4 - Nomenclature
By Todd Rothman
Copyright 2013
I. Alkane Nomenclature ............................................. 02
II. Cycloalkane and Bicycloalkane nomenclature ...... 10
III. Functional Group Nomenclature ......................... 14
7/23/2019 OC1 Chapter 4 Nomenclature (1)
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I. Alkane Nomenclature
1. Unbranched nomenclature
# of carbons formula IUPAC Name
1 CH4
methane
2 CH3CH
3ethane
3 CH3CH
2CH
3propane
4 CH3CH
2CH
2CH
3butane
5 CH3CH
2CH
2CH
2CH
3pentane
6 CH3CH
2CH
2CH
2CH
2CH
3hexane
7 CH3CH
2CH
2CH
2CH
2CH
2CH
3heptane
8 CH3CH
2CH
2CH
2CH
2CH
2CH
2CH
3octane
9 CH3CH
2CH
2CH
2CH
2CH
2CH
2CH
2CH
3nonane
10 CH3CH
2CH
2CH
2CH
2CH
2CH
2CH
2CH
2CH
3decane
2 types of nomeclature rules:
- International Union of Pure and Applied Chemistry (IUPAC)
systematic method for determining the name of a molecule
- Common Nomenclature
either semisystematic or unsystematic. Often the name is derived from the source of the compound
example:Formic acid comes from formica which is latin for ant, where this acid is found.
Organic Chemistry 1 - Nomenclature
Copyright 2013 - By Todd Rothman
7/23/2019 OC1 Chapter 4 Nomenclature (1)
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2. branched alkane nomenclature
General Nomenclature Rules:
Step 1. Find the parent carbon chain
Step 2. Number the atoms in the parent carbon chain
Step 3. Determine the name and number of the substituents
Step 4. Put the name together
Substituents - any branching groups off the parent carbon chain
How to name alkane substituents:
remove the "ane" from the end of the alkane name and add "yl"
methane --> methyl
ethane --> ethyl
propane --> propyl
butane --> butyl
pentane --> pentyl
hexane --> hexyl
heptane --> heptyl
octane --> octyl
nonane --> nonyl
decane --> decyl
Halogens are easy to name solets add them to our list:
Rule:
remove the "ine" from the end of
the halogen name and add "o"
(F) fluorine --> fluoro
(Cl) chlorine --> chloro
(Br) bromine --> bromo
(I) iodine --> iodo
Organic Chemistry 1 - Nomenclature
Copyright 2013 - By Todd Rothman
7/23/2019 OC1 Chapter 4 Nomenclature (1)
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Step 1 - Find the Parent carbon chain
Find the longest continuous chain of carbons. you must start from 1 end of the moleculeto the other. It does not have to be a straight line across:
If you have 2 or more ways to get the same number of continuous carbons, then use thepath with the most branching:
Br
Organic Chemistry 1 - Nomenclature
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Step 2 - Number the atoms in the carbon chain to find the parent chain
If the first substituent is the same distance for both ends, then give the secondsubstituent the lowest possible number. Repeat this until there is a difference
first substituent should have the lowest number
If you can number both ends and get the same low numbers then go with alphabetical prioirty
substituent = branch
Br
Organic Chemistry 1 - Nomenclature
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Step 3. Determine the name and number of the substituents
- use the numbers from the previous step to designate their location
- if 2 or more are the same substituent use the prefix di, tri, tetra, penta, hexa)
Br
Organic Chemistry 1 - Nomenclature
Copyright 2013 - By Todd Rothman
7/23/2019 OC1 Chapter 4 Nomenclature (1)
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Step 4 - Put the name together
#-substitutent + parent
- numbers are separated by commas
- numbers and letters are separated by hyphens
- each substituent must have its own number even if it is the same or on the same carbon
- alphabetize the names of the substituents to determine the order. Ignore all prefixesexcept iso
Br
Organic Chemistry 1 - Nomenclature
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7/23/2019 OC1 Chapter 4 Nomenclature (1)
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3. Common names for complex substituents
a. iso unit
parent
parent
iso can be larger than 3 carbons, for example:
isopropyl isobutyl
parent
isopentyl
b. butyl units
parent
parent
butyl (normal)
n-butyl
sec-butyl
parent
note: parent refers to the parent that
these substituents are bonded to
tert-butyl
c. neo unit
parent
neopentyl
Sometimes the substituents will not be a straight chain of carbons. Fortunately, there areseveral common names that we can learn to name these complex branches.
d. other common names to remember
parent parent
allyl vinyl
Organic Chemistry 1 - Nomenclature
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7/23/2019 OC1 Chapter 4 Nomenclature (1)
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Examples of complex substituent nomenclature
Cl
Cl
a.
b.
c.
Organic Chemistry 1 - Nomenclature
Copyright 2013 - By Todd Rothman
7/23/2019 OC1 Chapter 4 Nomenclature (1)
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II. Cyclo & Bicyclo Nomenclature
1. Cycloalkanes, cycloalkenes, and cycloalkynes
Substituent + Prefix + infix + suffix
Substituents - all branches off the parent chain.
branches include alkyl groups and halides
all substituents must have a number to identify it's location
we use di, tri, tetra, penta to emphasize the same group
Prefix - start with cyclo then add meth, eth, prop, but, pent, hex, hept, oct, non, dec
infix - an , en, yn
- en and yn need a number to tell us where the d-bond or t-bond begins
- The number can come before the prefix or before the infix
- The d-bond or t-bond has the highest prioirty for hydrocarbons. So it must be #1 & 2
suffix - add an "e" to the end of the name.
(Note: when we learn about naming functional groups, we will see many more suffix names. This is why we seperate infix from suffix.)
General Rules-
- when organizing the name it is based on alphabetical priority and not numerical priority
- The prefixes (di, tri, tert, sec, neo) are ignored when alphabetizing except for iso
- if there is only 1 substituent off the ring then you do not need to site the position. It is always assumed to be position 1
- if there is more than 1 substituent, begin numbering at one of the substituents and continue clockwise or counterclockwise to get the next substituent the second lowest number
- if only 2 substituents assign the first postion to the substituent that has alphabetical prioirty
- never name the compound a parent that includes the ring and straight chain. It is either a ring as the parent or a chain as the parent
- if the number of carbons in the ring is equal or greater than the number of carbons in the straight chain, the parent is a ring
PARENT CHAIN
Organic Chemistry 1 - Nomenclature
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7/23/2019 OC1 Chapter 4 Nomenclature (1)
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BrBr
Examples:
Br
Br
Cl
Cl
a. b.
d. e.
f. g.
c.
Organic Chemistry 1 - Nomenclature
Copyright 2013 - By Todd Rothman
7/23/2019 OC1 Chapter 4 Nomenclature (1)
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2. Bicycloalkane nomenclature
bicyclo[x.y.z]parent
bicyclo - all fused ring systems begin their name with a reference to the number of rings
(bicyclo = 2 rings tricyclo = 3 rings tetracyclo = 4 rings)
xyz - this tells us the number of carbons for each side of the ring. All bicyclo rings have 3 sides even if one side has no carbons. The circled red represent bridge carbons. These are carbons that connect all ring sides together. We do not include the red carbons when numbering the sides of the ring.
parent - This is the full name of the cyclic system. this name is derived from the total
number of carbons in the ring (including the bridge carbons)
bicyclo not bicyclo tricyclo
(must be fused)
4.4.0 4.4.1 3.2.1
bicyclo[4.4.0]decane bicyclo[4.4.1]undecane bicyclo[3.2.1]octane
Organic Chemistry 1 - Nomenclature
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7/23/2019 OC1 Chapter 4 Nomenclature (1)
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Bicycloalkane nomenclature examples
Cl
Cl
Br
a. b.
c. d.
e.
Br
Cl
f.
Organic Chemistry 1 - Nomenclature
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7/23/2019 OC1 Chapter 4 Nomenclature (1)
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suffix - functional group reference (has a number to tell us where it is unless C1)
COOH = oic acid
aldehyde = al
ketone = one
OH = ol
N = amine
alkane, alkene, alkyne - e
Substituent + Prefix + infix + suffix
Substituents - all branches off the parent chain.
branches include alkyl groups and halides
all substituents must have a number to identify it's location
we use di, tri, tetra, penta to emphasize the same group
Prefix - meth, eth, prop, but, pent, hex, hept, oct, non, dec
infix - an , en, yn
- en and yn need a number to tell us where it begins
- The number can come before the prefix or before the infix
Suffix has the highest priority whennaming structures. The functionalgroup that makes up the suffix portionof the name must have the lowestpossible number when numbering theparent chain. So whichever end isclosest to the functional group isnumber 1
priority
General Rules-
- when organizing the name it is based on alphabetical prioirty and not numerical priority
- all prefixes (di, tri, tert, sec, neo, etc.) are ignored when alphabetizing except for iso.
- if there is a substituent attached to Nitrogen of an amine or amide we identify it by writing a capital N instead of a number. In this context, "N" is treated like a number
PARENT CHAIN
General Nomenclature Rules Including Some Functional Groups
III. Functional Group Nomenclature
Organic Chemistry 1 - Nomenclature
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7/23/2019 OC1 Chapter 4 Nomenclature (1)
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Functional group nomenclature examples
Amines
NH N Br
Br
Alcohols
OH
OH
OH
Br
Cl
N Cl
OH
OH
Organic Chemistry 1 - Nomenclature
Copyright 2013 - By Todd Rothman
7/23/2019 OC1 Chapter 4 Nomenclature (1)
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Functional group nomenclature examples
ketones, aldehydes, and carboxylic acids
O O Br
O
Cl
O
Cl OH
O
Br
Br
O
OH
Organic Chemistry 1 - Nomenclature
Copyright 2013 - By Todd Rothman