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IUPAC Naming Questions-Substituents and Bonds

by Conservation
Tags: bonds, iupac, naming
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Apr18-14, 08:54 PM
Conservation's Avatar
P: 32
Hi all, couple of questions in the Official IUPAC naming rules for organic compounds:

1. How do I name organic molecules with both double/triple bonds and substituent? Do I name Both? For ex.: 2-Methyl-4-pentene vs. 2-Methylpentene?
2. If the double/triple bond and the substituent is in the same respective positions for either direction of the numbering, which is preferred? For example, for 2-Methyl-4-pentene (not sure if this is right yet, but...), is 4-Methyl-1-Pentene more correct as it has a numbering system with overall lower numbers? (4+1<2+4)

Thank you.
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Apr24-14, 09:19 AM
Sci Advisor
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DrClaude's Avatar
P: 1,427
You must number the double bond, and the double bond has precedence when numbering. The correct name is therefore 4-methyl-1-pentene.

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