August 12, 2020, 05:13:05 PM
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Topic: Nomenclature for 1,1-dimethylethyl cyclopentane  (Read 133 times)

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Offline tissueagenda

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Nomenclature for 1,1-dimethylethyl cyclopentane
« on: July 29, 2020, 05:45:59 AM »
Hi everyone, studying chemistry again after a really long time.

I was going through Khan Academy videos, in the end there was a cyclopentane with a tertbutyl. For the systematic naming, why is the longest chain not a propyl? My brain also can't wrap around the 1,1 dimethyl ethyl, could someone explain it please?

Thank you

Offline Babcock_Hall

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Re: Nomenclature for 1,1-dimethylethyl cyclopentane
« Reply #1 on: July 29, 2020, 10:34:47 AM »
Which has more carbon atoms, the tertiary-butyl group or the ring?

Offline Enthalpy

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Re: Nomenclature for 1,1-dimethylethyl cyclopentane
« Reply #2 on: July 30, 2020, 05:12:19 PM »
You need to name the tert-butyl keeping in mind which carbon makes a link with the cyclopentane.

I naming it methylpropyl, a different carbon would link to the cyclopentane. That would mean an isobutyl, not a tert-butyl.

So if you must call it ethyl, the branches can only be dimethyl. And because the name is long, normally you write t-butyl.

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