Nomenclature for Cyclo compounds

[bodmon]

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This compound is named 2-bromo-5,5,- dimethylcyclohexanol

I am curious to know why it can't be named 6-bromo-3,3-dimethylcyclohexonol; since the Carbon #'s would add up to a smaller total. Unless if you don't add the Carbon number for the double substituent twice?

Can someone clarify please

EDIT: 6-bromo, not 5 Bromo as i had it labelled before

 

[Mushibachan]

This compound is named 2-bromo-5,5,- dimethylcyclohexanol

I am curious to know why it can't be named 5-bromo-3,3-dimethylcyclohexonol; since the Carbon #'s would add up to a smaller total. Unless if you don't add the Carbon number for the double substituent twice?

Can someone clarify please

you want the name that corresponds to using the "smallest number" - for your case there's a 2-bromo and a 3,3-dimethyl as your lowest number... IUPAC states that you use the name for the lowest possible number

 

[Carbohydrates]

This compound is named 2-bromo-5,5,- dimethylcyclohexanol

I am curious to know why it can't be named 5-bromo-3,3-dimethylcyclohexonol; since the Carbon #'s would add up to a smaller total. Unless if you don't add the Carbon number for the double substituent twice?

Can someone clarify please

IUPAC naming says that you have to assign the substituents as low as possible. If you number C-OH is 1, and go clockwise, it 1,3,3,6. But if you go counter clockwise, it 1,2,5,5. Thus the counterclockwise is the correct numbering.

 

[bodmon]

you want the name that corresponds to using the "smallest number" - for your case there's a 2-bromo and a 3,3-dimethyl as your lowest number... IUPAC states that you use the name for the lowest possible number

IUPAC naming says that you have to assign the substituents as low as possible. If you number C-OH is 1, and go clockwise, it 1,3,3,6. But if you go counter clockwise, it 1,2,5,5. Thus the counterclockwise is the correct numbering.

I read your replies and came back to the question again and realized I was viewing it wrong

Clockwise and Counter-Clockwise give the same total 'number' when naming the substituents, so its a numerical tie. Next you resort to alphabetical ordering and Bromo would be the priority in that case.

 

[Carbohydrates]

I read your replies and came back to the question again and realized I was viewing it wrong

Clockwise and Counter-Clockwise give the same total 'number' when naming the substituents, so its a numerical tie. Next you resort to alphabetical ordering and Bromo would be the priority in that case.

Actually, I didn't even think about the total 'number', I just thought oh in cw, it goes 1 then 3. In ccw, it goes 1 then 2. So the ccw has to be it. But I could be wrong. 🙂

 

[bodmon]

Actually, I didn't even think about the total 'number', I just thought oh in cw, it goes 1 then 3. In ccw, it goes 1 then 2. So the ccw has to be it. But I could be wrong. 🙂

When there are two substituents your method is fine since you're looking for the least amount of difference. It is usually best to refer to the total number of substituents when numbering with more complex molecules.