Naming Cycloalkanes If ambiguity exists,number H3C、6 1CH2CH3 carbon atoms so that third or fourth substituent has lowest -CH3 number possible. 3 1-Ethyl-2,6-dimethylcycloheptane H3C、4 2CH2CH3 Higher NOT CH3 6 H3C. CH2CH3 2-Ethyl-1,4-dimethylcycloheptane CH3 Lower Lower 6 5 3-Ethyl-1,4-dimethylcycloheptane Higher LmingAl Pigh ReerdNaming Cycloalkanes ▪ If ambiguity exists, number carbon atoms so that third or fourth substituent has lowest number possible