CHEM 2211 1st Edition Lecture 4 Outline of Last Lecture I Alkyl group formation II Addition of Functional groups III Naming of Iso structures IV Naming of sec and tert butyl structure V Naming Alkanes Outline of Current Lecture I What are cycloalkanes II Rules for Nomenclature III Alcohols I How alcohols are formed II Rules for Nomenclature Vocabulary Cycloalkane Alcohol Current Lecture I II Cycloalkanes are alkanes in a ring formation a They have two fewer hydrogens than straight chain alkanes Rules for naming cycloalkanes a Add the prefix cyclo to the beginning of the name that signifies the number of carbons on the parent chain Cyclopropane Cyclobutane Cyclopentane b The cycloalkane is considered the parent chain unless a straight chain substituent has more carbons Then the straight chain is the parent chain and the cycloalkane is the substituent i If only one substituent exists then no numbers are needed to identify its place on the cycloalkane Methylcyclopentane 1 cyclobutylpentane c When two substituents are present on the ring then the first one alphabetically is the number one substituent 1 methyl 2 propylcyclohexane 1 ethyl 3 methylcyclopentane d When a cycloalkane has more than two substituents the number 1 substituent is the one that results in the lowest number for the second substituent 1 1 2 trimethylcyclopentane 4 ethyl 2 methyl 1 propylcyclopentane NOT NOT 1 2 2 trimethylcyclopentane 1 ethy 3 methyl 4 propylcyclohexane NOT NOT 1 1 5 trimethylcyclopentane 5 ethyl 1 methyl 2 propylcyclohexane Alcohols I II Alcohols are formed when an OH attaches to an alkyl group a They can be primary secondary or tertiary depending on whether the carbon they are attached to is primary secondary or tertiary Rules for naming alcohols a By dropping the e and the end of an alkane name and adding the suffix ol Methanol Ethanol i IUPAC recently has changed the nomenclature for alcohols 3 pentanol OR pentan 3 ol b The parent chain is the longest chain that CONTAINS the OH functional group c The OH group has the lowest possible number when numbered on the parent hydrocarbon 2 butanol OR butan 2 ol 3 butoxy 1 propanol OR 3 butoxypropan 1 ol d The suffix diol is added to compounds with two OH groups on the parent chain 4 2 hexanediol OR hexane 2 4 diol e When both a functional group and a substituent are present the functional group gets the lowest number 3 bromo 1 propanol f If both a functional group and the OH group have the same number when numbered from both directions then the functional group gets the lowest number 2 chloro 3 penthanol NOT 4 chloro 3 pethanol 3 methylcyclohexanol NOT 5 methylcyclohexanol g When more than one substituent is present on an alcohol then they are listed alphabetically 7 bromo 4 ethyl 2 octanol 3 4 dimethylcyclopentanol
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