Cyclic hydrocarbons

Important for proper working order of human body (examples: steroids – testosterone and estrone, cholesterol) Important medicinal uses – ex. Budesonide (asthma treatment) 3. Cholesterol

In some hydrocarbons the carbons at the ends of the chain join together to form a ring and are called cyclic hydrocarbons.

Naming Cyclic Hydrocarbons Cycloalkanes are named using the alkane parent with the prefix cyclo. cyclopropanecyclobutane cyclopentane cyclohexane cycloheptane

The general formula for the cycloalkanes is C n H 2n. With what homologous series are cycloalkanes isomeric? Alkene

Naming Branched Cycloalkanes If there is only one branch, no number is needed. methylcyclopentane ethylcyclohexane CH 2 – CH 3

If there are two branches, the # 1 carbon would be the one with substituent listed first in the alphabet. Number toward the second branch in the direction which yields the lower number for the carbon bearing that second branch. CH 3 CH 3 – CH 2 1-ethyl-3-methylcyclohexane 1,1-dimethylcyclopropane CH 3

When more than two branches are resent, each must have the lowest possible position number. 3-ethyl-6-methyl-1-propylcycloheptane 1-ethyl-5-methyl-3-propylcycloheptane CH 2 – CH 3 CH 3 CH 3 –CH 2 –CH 2

Naming Cycloalkenes If double bond is present in the ring structure, you must follow the same rules as for alkenes. DOUBLE BOND GETS PRIORITY FOR THE LOWEST NUMBER!!! CH 3 3-methyl-1-cyclohexene CH 3 CH 3 – CH 2 5-ethyl-3-methyl-1-cyclohexene

Sample problem 1 Name the following structures c) CH 3 CH 3 – CH 2

Sample problem 1 Name the following structures c) CH 3 CH 3 – CH 2 a)1,3-dimethylcyclohexane b) Ethylcyclopropane c) 1-ethyl-2-methyl-1-cyclopentene d) 1-methyl-3-propylcyclohexane

Sample Problem 2 Draw a condensed structural diagram for following compounds: a)1,1-dimethylcyclobutane b)ethylcyclopentane c)1-bromo-3-ethylcyclobutane d)3-bromo-1-ethyl-1-cyclobutene

Complete questions p.358 #30,31 a) b) CH 3 CH 2 – CH 3 Br CH 2 – CH 3 Br c) d)