1. CHAPTER 5: NOMENCLATURE
ORGANIC CHEMISTRY
CHAPTER 5: NOMENCLATURE
Brown et al. Chapter p
HYDROCARBONS
Alkanes: CnH2n+2
sp3 hybridization
Alkenes: CnH2n
sp2 hybridization
Alkynes: CnH2n-2
sp hybridization
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2. 1: sp
2: sp
3: sp2
4: sp2
5: sp3
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3. Shorthand =
C10H22
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4. 6-C Rings =
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5. FUNCTIONAL GROUPS ALCOHOLS propanol phenol
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6. ALDEHYDES methanal ethanal propanal
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7. KETONES CARBOXYLIC ACIDS propanone butanone
methanoic acid ethanoic acid
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8. ESTERS ETHERS ethyl ethanoate ethyl methyl ether
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9. AMINES AND NITRILES amine nitrile 1o amine 2o amine 3o amine
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10. AMIDES
hexanamide
ARENES
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11. NAMING COMPOUNDS
Rule 1: Choose the longest carbon chain to base the name upon.
Rule 2: Number the carbons in this longest chain beginning at the end nearest the first branch point.
Rule 3: Identify and number the branches.
methyl ethyl propyl butyl pentyl
isopropyl sec-butyl tert-butyl isobutyl
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12. EXAMPLE SOLUTION Name the following molecule:
The longest carbon chain is seven atoms long.
Therefore our name will be based upon heptane.
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13. Number the chain to give the following:
By numbering in this manner the branches are on the lowest carbon numbers possible, i.e. C3 and C4.
We have a methyl group on C3 and a methyl group on C4
We can now write the name as 3,4-dimethylheptane.
WHEN NAMING ORGANIC COMPOUNDS USE HYPHENS TO SEPARATE NUMBERS AND LETTERS, AND COMMAS TO SEPARATE NUMBERS.
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14. EXAMPLE SOLUTION Name the following molecule:
The longest carbon chain is ten carbons
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15. The compound is thus 6-ethyl-3,5-dimethyldecane
We identify the methyl substituents on carbon C3 and C5 and an ethyl substituent on C6.
The compound is thus 6-ethyl-3,5-dimethyldecane
WHEN DECIDING WHICH SUBSTITUENTS TO PUT FIRST, SIMPLY PUT THEM IN ALPHABETICAL ORDER. ETHYL THUS COMES BEFORE METHYL (NOTE: WE DON’T COUNT THE PREFIX, DI- IN THIS CASE, WHEN DECIDING THIS ORDER).
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16. C – primary - 1° C – secondary - 2° C – tertiary - 3°
C – quaternary - 4°
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17. NAMING COMPOUNDS WITH FUNCTIONAL GROUPS
The parent hydrocarbon chain is the longest continuous carbon chain containing the highest priority functional group.
Functional Group Name
-COOH carboxylic acid COOR ester
-COX acid halide, X = Cl, Br
-CONH2 amide
-CHO aldehyde
RCOR’ ketone
-OH alcohol
-NH2 amine
CnH2n-2 alkyne
CnH2n alkene
CnH2n+2 alkane
highest priority
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18. 2,2-dichloropentan-3-ol , NOT 4,4-dichloropentan-3-ol.
The chain is numbered in the direction that gives the highest priority functional group the lowest possible number.
If the same number for the functional group is obtained in both directions the chain is numbered in the direction that gives the substituent the lowest number.
2,2-dichloropentan-3-ol , NOT 4,4-dichloropentan-3-ol.
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19. EXAMPLE SOLUTION Name the following compound:
The parent hydrocarbon is five carbons long
The suffix will be –oic acid; The substituents are 3-methyl and 4-chloro.
Thus, we have 4-chloro-3-methylpentanoic acid.
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20. EXAMPLE SOLUTION Name the following compound:
The highest priority functional group is the aldehyde.
Thus the parent chain is numbered:
Therefore the name is 5-hydroxy-5-methylhexanal
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21. 4-aminopentanoic acid 4-chloropentan-2-ol
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