Okay, when you are naming organic molecules with the IUPAC rules, the sidegroups are ordered alphabetically.

Example: 3-bromo-1-chloropentane
bromo comes before chloro.

Prefixes for amount of sidegroups do not affect the order.
Example: 2-ethyl-5,5-dimethylheptane

But what about the common prefixes, such as iso?

Would an isobutyl group come before an ethyl group? Or would the ethyl group come before the isobutyl group?

I realize how this is just a technicality, but I get bonus point in my organic chem class if I can find a straight answer to this question. :D

i am pretty sure that the iso part isn't counted, so isobutyl is before ethyl or chloro.

i am pretty sure that the iso part isn't counted, so isobutyl is before ethyl or chloro.

That's what I always thought too. I need more answers to clarify that though.

why not fucking look it up yourself.

google chloro and isobutyl and see what shows up.

why not fucking look it up yourself.

google chloro and isobutyl and see what shows up.

http://butane.chem.uiuc.edu/cyerkes/Chem104A_BFA05/Genchemref/nomenclature_rules.html

With a little digging I found my answer. Iso is the only prefix that matters, all others are ignored.

I was hoping someone here might know offhand, but it's such a technicality.

Did your teacher ever say the answer to that question?

Cause the way i learned it when taking ochem (2 years ago), isopropyl isn't even an IUPAC. (along with sec, tert, etc.) so how can you even compare/rank common names (ie: isopropyl) alongside IUPAC format? Forgive me if YOU CAN because i really dont know, but it just seems a bit weird to me.

if i was you id just tell the teacher its 1-methyethyl and do it as you would any other iupac substituent

^ this, but chemicals in real life are often named bastardized forms of IUPAC and common nomenclature, just learn the rules and be able to visualize, past that the only thing that will help you is practice