CHAPTER 5: NOMENCLATURE ORGANIC CHEMISTRY CHAPTER 5: NOMENCLATURE Brown et al. Chapter 21- 27 p 794- 1031 HYDROCARBONS Alkanes: CnH2n+2 sp3 hybridization Alkenes: CnH2n sp2 hybridization Alkynes: CnH2n-2 sp hybridization CHEM171 – Lecture Series Five : 2012/01

1: sp 2: sp 3: sp2 4: sp2 5: sp3 CHEM171 – Lecture Series Five : 2012/02

Shorthand = C10H22 CHEM171 – Lecture Series Five : 2012/03

6-C Rings = CHEM171 – Lecture Series Five : 2012/04

FUNCTIONAL GROUPS ALCOHOLS propanol phenol CHEM171 – Lecture Series Five : 2012/05

ALDEHYDES methanal ethanal propanal CHEM171 – Lecture Series Five : 2012/06

KETONES CARBOXYLIC ACIDS propanone butanone methanoic acid ethanoic acid CHEM171 – Lecture Series Five : 2012/07

ESTERS ETHERS ethyl ethanoate ethyl methyl ether CHEM171 – Lecture Series Five : 2012/08

AMINES AND NITRILES amine nitrile 1o amine 2o amine 3o amine CHEM171 – Lecture Series Five : 2012/09

AMIDES hexanamide ARENES CHEM171 – Lecture Series Five : 2012/10

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 CHEM171 – Lecture Series Five : 2012/11

EXAMPLE SOLUTION Name the following molecule: The longest carbon chain is seven atoms long. Therefore our name will be based upon heptane. CHEM171 – Lecture Series Five : 2012/12

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. CHEM171 – Lecture Series Five : 2012/13

EXAMPLE SOLUTION Name the following molecule: The longest carbon chain is ten carbons CHEM171 – Lecture Series Five : 2012/14

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). CHEM171 – Lecture Series Five : 2012/15

C – primary - 1° C – secondary - 2° C – tertiary - 3° C – quaternary - 4° CHEM171 – Lecture Series Five : 2012/16

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 CHEM171 – Lecture Series Five : 2012/17

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. CHEM171 – Lecture Series Five : 2012/18

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. CHEM171 – Lecture Series Five : 2012/19

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 CHEM171 – Lecture Series Five : 2012/20

4-aminopentanoic acid 4-chloropentan-2-ol CHEM171 – Lecture Series Five : 2012/21