naming carbon compounds

[Nomvalt]

What is the name of this compound?


  H Cl  H H  H H  H
   |  |  |  |  | |  |
H-C-C-C-C-C-C-C-H
   |  |  | |  | |  |
   H  H H Br H H H


Why is it 4-bromo-2-choloroheptane?
Why isn't 2-choloro-4-bromoheptane right?
How do you know whether to put the '4-bromo' or '2-choloro' in front?  

Edit: actually, I think if you have two halogens you just write the prefixes in alphabetical order...would anyone be able to confirm?

[vexx]

Well the second carbon starting from the left is Chloro, and the fourth is Bromo, i don't think it matters too much really but i'd be more inclined to do 2-chloro-4-bromo since you started counting from the chloro side. they wouldn't take marks off you for doing the other way around though.

[Mao]

Edit: actually, I think if you have two halogens you just write the prefixes in alphabetical order...would anyone be able to confirm?

I am pretty sure this is the case [though I could be mistaken, haven't done nomenclature for a while]

[kyzoo]

In the systematic name, you generally order functional groups according to alphabetical order. So it's 2-chloro-4-bromoheptane. 4-bromo-2-chloroheptane

EDIT: Matty is pro 

[m@tty]

Kyzoo, b is before c in the alphabet..

I think it's meant to be 4-Bromo-2-ChloroHeptane.

[vexx]

Arghh, my teacher told us that what i said above.

Whatever, i'm sure it doesn't matter anyway if i do it the slightly incorrect way?

[kyzoo]

Arghh, my teacher told us that what i said above.

Whatever, i'm sure it doesn't matter anyway if i do it the slightly incorrect way?

It's better if you just follow the rules. This is a simple case with just 2 functional groups, but there are often more. e.g. 4-chloro-3-diethyl-2-hydroxy-4-methylnonanoic acid or something like that.

[vexx]

Arghh, my teacher told us that what i said above.

Whatever, i'm sure it doesn't matter anyway if i do it the slightly incorrect way?

It's better if you just follow the rules. This is a simple case with just 2 functional groups, but there are often more. e.g. 4-chloro-3-diethyl-2-hydroxy-4-methylnonanoic acid or something like that.

ah ok. thanks, i guess i'll just do it that way then.

[stonecold]

yahh, and when numbering your carbons, double and triple bonds take priority over any functional/branch groups...

i.e.

   Cl H  H H  H H H
   |  |  |  |  | |  |
H-C-C-C-C-C-C=C-H
   |  |  | |  |  |  |
   H  H H Br H H  H

is 4-bromo-7-chloro-hept-1-ene

[Souljette_93]

yahh, and when numbering your carbons, double and triple bonds take priority over any functional/branch groups...

i.e.

   Cl H  H H  H H H
   |  |  |  |  | |  |
H-C-C-C-C-C-C=C-H
   |  |  | |  |  |  |
   H  H H Br H H  H

is 4-bromo-7-chloro-hept-1-ene

I've always known that functional groups are preferred over the double bonds, but not with the subsituents ( Chloro, bromo..)


Souljette

[physics]

4- bromo- 2-cloro heptane
alphabetical order...

[stonecold]

yahh, and when numbering your carbons, double and triple bonds take priority over any functional/branch groups...

i.e.

   Cl H  H H  H H H
   |  |  |  |  | |  |
H-C-C-C-C-C-C=C-H
   |  |  | |  |  |  |
   H  H H Br H H  H

is 4-bromo-7-chloro-hept-1-ene

I've always known that functional groups are preferred over the double bonds, but not with the subsituents ( Chloro, bromo..)


Souljette

This is just what my teacher told us.  We went into a pretty heated discussion/google sesh in class to find out. 

Can anyone clarify please...

[superflya]

according to this http://en.wikipedia.org/wiki/IUPAC_nomenclature_of_organic_chemistry   functional groups first.

[physics]

hirachy

functional groups > bonds > alkyl halides > alkyl groups

[stonecold]

starting to lose faith in my teacher. 
not good!