Confusion on naming on page 93 on Course Reader

Jamie Huang 1L
Posts: 20
Joined: Fri Jul 15, 2016 3:00 am

Confusion on naming on page 93 on Course Reader

I know Dr.Lavelle tried to explain the organic molecule on page 93 in class, but I'm still confused about the part where he named it 4-Ethyl-2,2-dimethyl-hexane instead of 3-Ethyl-5,5-dimethyl-hexane ? I thought we were supposed to choose the number Carbon that gives the smallest number for the first number, and it seems like this is an exception? How do we know in future cases to choose 4 instead of 3? or any similar cases but with different numbers.

I remember he said something about 3 bigger than 2, so would we look at the first number and second number and compare?, meaning if we have two options we compare the second numbers of both names to the first number of the two possible naming and see which one is smaller?

Pauline Tze 3B
Posts: 57
Joined: Sat Jul 09, 2016 3:00 am
Been upvoted: 1 time

Re: Confusion on naming on page 93 on Course Reader

Hi Jamie,

If you write out the numbers in numerical order you get
224
355
You look for the one with the lowest number, which is the group with 2.This is regardless of its position in the molecule.

samuelkharpatin2b
Posts: 55
Joined: Wed Sep 21, 2016 2:57 pm

Re: Confusion on naming on page 93 on Course Reader

The combination of 4,2,2 is smaller than the combination of 3,5,5. Hence, you use the combination of 4,2,2 and then you arrange the name based on alphabetical order. You ignore prefixes like di- tri- etc when considering alphabetical order.