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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: Aakash on December 06, 2013, 08:56:32 AM

Title: Nomenclature-What is the difference between these two?
Post by: Aakash on December 06, 2013, 08:56:32 AM
The compound is 5-(1-Methylethyl)-2-methyl-octane

can we write it like   2-methyl-5-(1-Methylethyl)-octane ? Why /why not?
Title: Re: Nomenclature-What is the difference between these two?
Post by: discodermolide on December 06, 2013, 10:06:56 AM
You mean this molecule?
CC(C)CCC(C(C)C)CCC

in that case the first is more correct, but methyl ethyl!! How about 5-isopropyl-2-methyloctane?

Title: Re: Nomenclature-What is the difference between these two?
Post by: Aakash on December 06, 2013, 01:58:40 PM
yes. That is the one. I read that each compound has unique name in IUPAC nomenclature. so only one of those two can be true?
Title: Re: Nomenclature-What is the difference between these two?
Post by: discodermolide on December 06, 2013, 02:05:20 PM
Find the longest chain.
The substituents must be placed in the name in alphabetical order.
The numbers must add up to the lowest total.
So 5-isopropyl-2-methyloctane is correct.
Title: Re: Nomenclature-What is the difference between these two?
Post by: Aakash on December 06, 2013, 02:07:49 PM
you said isopropyl but I read that iso was used in trivial naming.
Title: Re: Nomenclature-What is the difference between these two?
Post by: discodermolide on December 06, 2013, 02:09:32 PM
Iso is an allowed prefix under IUPAC.
Title: Re: Nomenclature-What is the difference between these two?
Post by: Aakash on December 06, 2013, 02:12:28 PM
Okay so both the names which I suggested in the question are wrong?
Title: Re: Nomenclature-What is the difference between these two?
Post by: discodermolide on December 06, 2013, 02:15:19 PM
Yes, unfortunately.