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11.3 Alkanes with SubstituentsWhen an alkane hasfour or more carbonatoms, the atoms can bearranged so that a sidegroup called a branch orsubstituent is attachedto a carbon chain.Learning Goal Write the IUPAC names for alkanes withsubstituents and draw their condensed structural formulas andskeletal formulas.Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition 2015 Pearson Education, Inc.Structural IsomersStructural isomers have the same molecularformula with a differentarrangement of atoms have the same numberof atoms bonded in adifferent orderButane, C4H10, has twostructural isomers: a straightchain and a branched chain.Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition 2015 Pearson Education, Inc.Study CheckDraw three possible structural isomers of pentane, C5H12.Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition 2015 Pearson Education, Inc.1
SolutionDraw three possible structural isomers of pentane, C5H12.Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition 2015 Pearson Education, Inc.Alkane SubstituentsSubstituents are atoms or groups of atoms attached to thecarbon chain and include alkyl and halo groups.Alkyl groups are groups of carbon atoms attached to carbon chains named in the IUPAC system with an yl endingHalo substituents are halogen atoms attached to the carbon chain named in the IUPAC system as fluoro, chloro, bromo,or iodo.Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition 2015 Pearson Education, Inc.Substituents and Alkyl GroupsChemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition 2015 Pearson Education, Inc.2
Guide to Naming Alkanes withSubstituentsChemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition 2015 Pearson Education, Inc.Study CheckGive the IUPAC name for the following compound:HHClHHHCCCCCHHCH3HHHChemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition 2015 Pearson Education, Inc.SolutionANALYZETHEPROBLEMType of CompoundalkaneSubstituentsone methyl groupone halo groupIUPAC Namingnumber chainfor substituentsSTEP 1 Write the alkane name of the longest chain ofcarbon atoms.HClHHThe longest chain hasHCCCCfive carbons—pentane.HChemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth EditionHCH3HHCHH 2015 Pearson Education, Inc.3
SolutionSTEP 2 Number the carbon atoms starting from the endnearest to a substituent.HH1CHCl2CHH3CCH3H4CH5HCHpentaneHSTEP 3 Give the location and name of each substituent (inalphabetical order) as a prefix to the name of themain chain.2-chloro-3-methylpentaneChemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition 2015 Pearson Education, Inc.Naming Cycloalkanes withSubstituentsWhen one substituent is attached to a carbon atom in acycloalkane, the name of the substituent is placed in front of thecycloalkane name no number is needed for a single alkyl group or halogen atomThe IUPAC name for the followingcycloalkane is ethylcyclohexane.Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth EditionCH2CH3 2015 Pearson Education, Inc.Naming HaloalkanesHaloalkanes are alkanes with a halogen atom that replaces a hydrogen atom are named by putting the substituents in alphabetical order have the halo group numbered according to the carbon whereit is attached to the alkaneChemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition 2015 Pearson Education, Inc.4
Drawing Formulas for AlkanesThe IUPAC name gives all the information needed to draw thecondensed structural formula for an alkane.di means “two”Draw the structure for 1-chloro-1,2-dimethylheptaneheptane: seven-carbon chainmethyl group on carbons 1 and 2chlorine on carbon 1Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition 2015 Pearson Education, Inc.Guide to Drawing Formulas forAlkanesChemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition 2015 Pearson Education, Inc.Study CheckDraw the condensed structural formula for3-bromo-1-chlorobutane.Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition 2015 Pearson Education, Inc.5
SolutionDraw the condensed structural formula for3-bromo-1-chlorobutane.STEP 1 Draw the main chain of carbon atoms.The longest chain in butanehas four carbon atoms.C—C—C—CSTEP 2 Number the chain and place the substituents on thecarbons indicated by the numbers. 1 2 3 43-bromo: — Br goes on carbon 3C—C—C—C1-chloro: — Cl goes on carbon 1Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth EditionClBr 2015 Pearson Education, Inc.SolutionDraw the condensed structural formula for3-bromo-1-chlorobutane.STEP 3 Add the correct number of hydrogen atoms to givefour bonds to each C atom.ClCH2—CH2—CH—CH3 ClBrBr3-bromo-1-chlorobutaneChemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition 2015 Pearson Education, Inc.Study CheckName each of the following alkanes:A.ClB.Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition 2015 Pearson Education, Inc.6
SolutionName each of the following alkanes:STEP 1 Write the alkane name of the longest chain ofcarbon atoms.A.The longest chain in pentane hasfive carbon atoms.ClB.The longest chain in pentane hasfive carbon atoms.Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition 2015 Pearson Education, Inc.SolutionName each of the following alkanes:STEP 2 Number the carbon atoms starting from the endnearer a substituent.A.53B.112-chloro: — Cl goes on carbon 2.2Cl435422,3-dimethyl: — CH3 goes oncarbons 2 and 3.Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition 2015 Pearson Education, Inc.SolutionName each of the following alkanes:STEP 3 Give the location and name of each substituent(alphabetical order) as a prefix to the name of themain ntane4Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition 2015 Pearson Education, Inc.7
3 Chemistry: An Introduction to General, Organic, and Biological Chemistry, Twelfth Edition 2015 Pearson Education, Inc. Guide to Naming Alkanes with
