Org. Chem I Handout #4 NOMENCLATURE OF ALKANES SOME COMMON GROUP NAMES: CH3- methyl
CH3CH2 - ethyl
CH3CH2CH2 - propyl
H
H 3C C
CH3
or
CH3CHCH3
isopropyl
CH3CHCH2 - isobutyl
CH3
CH3CH2CH2CH2 - butyl
CH3CH2CHCH3 - sec-butyl
CH3
H 3C C
CH3
CH3
CH3CH2C
CH3
- tert-pentyl
- tert-butyl
CH3
H3C C CH2
CH3
- neopentyl
Acyclic alkanes – general molecular formula = CnH2n+2 Realize that with alkanes containing 4 carbons or more, constitutional isomers can exist: Five isomers of C6H14 hexane
2-methylpentane
3-methylpentane
2,2-dimethylbutane
2,3-dimethylbutane **Make sure you can convert these skeletal structures to condensed and/or Lewis structures!! Naming acyclic alkanes AND identifying 1° (primary), 2° (secondary), 3° (tertiary) and 4° (quaternary) carbons and hydrogens Consider this compound: CH2CH3
H3C CHCH2 C CH3
CH3
CH3
Name this compound using the rules you have learned. Label the primary, secondary, tertiary and quaternary carbons. Related problems in the book are 4.3 and 4.10. Copyright © Doug E. Frantz The University of Texas at San Antonio Org. Chem I Handout #4 Cyclic alkanes and nomenclature: Prefix + cyclo + parent + suffix = NAME Example: ‐
‐
‐
‐
methyl group
CH3
3
2
H3C
4
1
6 carbons in the ring = cyclohexane identify the two groups isopropyl group gets #1 since it has alphabetical priority number carbons in the ring 5
NAME = 1‐isopropyl‐4‐methylcyclohexane 6
CH3
isopropyl group
Common names: In the older literature, many organic compounds were given common names that do not follow the IUPAC system of nomenclature. Example: IUPAC name = 2-methylbutane
common name = isopentane Others have had names assigned to them based on their structure or properties: churchane
windowpane
basketane
SUGGESTED PROBLEMS FOR EXAM I Chapter 1 41, 44, 45, 47­58, 60, 62, 63, 64, 68, 69­71, 78, 81, 84, 86, 91 Chapter 2 36, 39, 46­48, 51, 53, 58, 62, 65, 67, 69, 71, 73 Chapter 3 19, 22, 24, 26, 32, 34, 36, 38, 49, 50 Chapter 4 36, 38, 39, 40, 42, 44, 47, 50, 52, 56, 58, 60, 62, 64, 65, 68, 69, 71, 73, 75, 77 Copyright © Doug E. Frantz The University of Texas at San Antonio