Rule 1:The Main Chain Find the longest chain of consecutive carbons. The longest chain is 2 CH,CH, six carbons: CH3-CH-CH2-CH2-CH, 3 4 6 hexane 3-methylhexane 2013 Pearson Education,Inc. Chapter 3 11
© 2013 Pearson Education, Inc. Rule 1: The Main Chain The longest chain is six carbons: hexane Find the longest chain of consecutive carbons. Chapter 3 11
Main Chain CH3 CH3 CH3 CH- CH2 CH3 CH CH2 CH CH- CH2CH3 CH- CH2CH: CH3 CH-CH3 CH3 CH- CH3 CH3 CH3 wrong correct seven-carbon chain,but only three substituents seven-carbon chain,four substituents 203 Pearsdn Educalion.inc When there are two longest chains of equal length,use the chain with the greatest number of substituents. 2013 Pearson Education,Inc. Chapter 3 12
© 2013 Pearson Education, Inc. Main Chain When there are two longest chains of equal length, use the chain with the greatest number of substituents. Chapter 3 12
HINT When looking for the longest continuous chain(to give the base name),look to find all the different chains of that length. Often,the longest chain with the most substituents is not obvious. 2013 Pearson Education,Inc. Chapter 3 13
© 2013 Pearson Education, Inc. When looking for the longest continuous chain (to give the base name), look to find all the different chains of that length. Often, the longest chain with the most substituents is not obvious. Chapter 3 13
Rule 2:Numbering the Main Chain Number the longest chain beginning at the end of the chain nearest a substituent. CH methy CH -CH2 CH CH ethyl CH- CH CHCH; CH-CH CH.CH: CH: CH CH3 CH CH CH, CH; methyl CH, methyl) incorrect correct 3-ethyl-2,4,5-trimethylheptane e20o的Eaon.能 2013 Pearson Education,Inc. Chapter 3 14
© 2013 Pearson Education, Inc. • Number the longest chain beginning at the end of the chain nearest a substituent. Rule 2: Numbering the Main Chain Chapter 3 14
Rule 3:Naming Alkyl Groups Alkane name Alkyl name CH4 methane -CHs methyl group CHgCH3 ethane -CH2CH3 ethyl group CHgCH2CH3 propane -CH2CH2CH3 propyl group CHgCH2CH2CH3 butane -CH2CH2CH2CH3 butyl group CH3CH2CH2CH2CH3 pentane -CH2CH2CH2CH2CH3 pentyl group 2013 Pearson Education,Inc. Chapter 3 15
© 2013 Pearson Education, Inc. Rule 3: Naming Alkyl Groups Alkane name Alkyl name CH4 methane –CH3 methyl group CH3CH3 ethane –CH2CH3 ethyl group CH3CH2CH3 propane –CH2CH2CH3 propyl group CH3CH2CH2CH3 butane –CH2CH2CH2CH3 butyl group CH3CH2CH2CH2CH3 pentane –CH2CH2CH2CH2CH3 pentyl group Chapter 3 15