4-ethyl-2,2-dimethylhexane vs 2,2-dimethyl-4-ethylhexane

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Yiling Liu 1N
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Joined: Sat Jul 09, 2016 3:00 am

4-ethyl-2,2-dimethylhexane vs 2,2-dimethyl-4-ethylhexane

Postby Yiling Liu 1N » Tue Feb 28, 2017 3:01 pm

in the "Introduction to Organic Chemistry" workbook on page 8, the book names the alkane 4-ethyl-2,2-dimethylhexane.

it says "the substituents are placed alphabetically (ethyl then dimethyl)"

but doesn't the letter "d" come before the letter "e"?

Is 2,2-dimethyl-4-ethylhexane also an acceptable answer?

If not, why?

Preston_Dang_1B
Posts: 22
Joined: Wed Sep 21, 2016 2:59 pm

Re: 4-ethyl-2,2-dimethylhexane vs 2,2-dimethyl-4-ethylhexane

Postby Preston_Dang_1B » Tue Feb 28, 2017 4:08 pm

The order is based on the first letter of the individual substituents regardless of the prefix in front. In other words, for dimethyl, it is the "m" that is ordered and not the "d." Therefore, ethyl would be written before methyl in the naming of the compound rather than the other way around because of the "di" prefix in front of the methyl.

Hope this helps!

samuelkharpatin2b
Posts: 55
Joined: Wed Sep 21, 2016 2:57 pm

Re: 4-ethyl-2,2-dimethylhexane vs 2,2-dimethyl-4-ethylhexane

Postby samuelkharpatin2b » Wed Mar 01, 2017 4:24 pm

When naming compounds, you are supposed to ignore the prefix. That is, you disregard the "di-" in dimethylhexane and use the first letter "m" when taking into account alphabetical order. This is the same for all prefixes.


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