quick naming question

[sunnys]

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Could someone please tell me which of the names below is correct:
1-methyl-3-isopropylcyclohexane
3-methyl-1-isopropylcylcohexane

if it's the second one is it because it's a heavier substituent and which is why it gets the higher priority(gets the 1-isopropyl)?

Just confused how to prioritize.

Thanks

 

[Rabolisk]

Neither. The answer should be 1-isopropyl-3-methylcyclohexane.

http://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/nomen1.htm

 

[TwoPaddles]

Could someone please tell me which of the names below is correct:
1-methyl-3-isopropylcyclohexane
3-methyl-1-isopropylcylcohexane

if it's the second one is it because it's a heavier substituent and which is why it gets the higher priority(gets the 1-isopropyl)?

Just confused how to prioritize.

Thanks

"iso" groups come before "methyl" in naming

 

[sunnys]

oh okay. so in isopropyl I do not ignore the iso part and since isopropyl is heavier it gets the 1 position.

but in sec-butyl and tert-butyl...I ignore the sec and tert when alphabetizing?

 

[sunnys]

found my answer. thanks.

"In alphabetizing, ignore prefixes like sec-, tert-, di, tri, etc., but
include iso and cyclo."

 

[Rabolisk]

The reason isopropyl gets 1 rather than methyl has nothing to do with being heavier. It has to do with the fact that i comes before m.

 

[TwoPaddles]

found my answer. thanks.

"In alphabetizing, ignore prefixes like sec-, tert-, di, tri, etc., but
include iso and cyclo."

When you have a "cyclo" though you still have to name the the substituent first.

Example: 3-isopropyl cyclohexanecarboxamide....
So even though "c" comes before in the alphabet, you always name the substituents first and then the cyclo part.

 

[Rabolisk]

I think what he means if a ring is named as a substituent, rather than as the main chain.