[Bassel]

i understand that for a branch to be iso the carbon connected to the main chain has to be primary and the one adjacent to the primary has to be secondary.

in my class notes there is a compound named : 5-isopropyl-2-methyloctane

                                       CH3
                                         |
CH3-CH2CH2-CH-CH2CH2-CH-CH3
                      |
                     CH-CH3
                      |
                     CH3

HOW IS THAT AN ISO, ISNT IT SEC??

thank you for your help.

[discodermolide]

Yes it is also a sec.
But IUPAC allows the use of iso as well.

[curiouscat]

That looks like a some-nonane to me...

Assuming this is what you meant:

[Archer]

i understand that for a branch to be iso the carbon connected to the main chain has to be primary and the one adjacent to the primary has to be secondary.

in my class notes there is a compound named : 5-isopropyl-2-methyloctane

                                       CH3
                                         |
CH3-CH2CH2-CH-CH2CH2-CH-CH3
                      |
                     CH-CH3
                      |
                     CH3

HOW IS THAT AN ISO, ISNT IT SEC??

thank you for your help.

How would you name this using 'sec' ?

Please provide your explanation

[Bassel]

@discodermolide , is it an exception or is there a rule for such compounds to be sec and iso at the same time ?

[discodermolide]

No rule as far as I am aware, iso-Butylalcohol and sec-Butylalcohol, both are allowed.
But you need to look at the entire molecule, not just that part containing the group you are interested in.