[redfox]

 

Hi, I'm having some difficulties naming a few compounds. Mainly 'cos my tutor explained how to name only simple compounds but assumed after that I knew enough to name anything! I'm sure they're not particularly difficult, but I don't know how to go about it and my chemistry book says it's not necessary to know how to name compounds:(

I've tried attaching pictures of those I am to name, but they're not showing up in the preview. Hope they show up when I actually post! If not I'll just try writing them somehow...

I really don't want to be told the names of them only (tho B I'd take a name!;) ) I need to learn how to do it myself.

So far I've decided that A is 4-chloro heptan-2-en-6-yneol...tho the last bit doesn't sound like a real name to me!

For B I really have no idea about the fluoros:( However to keep numbers small I think the CF₂CF₃ would be on C3. So something like 3-(CF₂CF₃)hept-5-yne

C - Again I'm not sure about the functional group attached, but the main chain I think is pent-1,4-diene...?

and D (says e on it) could be something like 2-trifluoromethyl-5-chlorohept-2,4-diene.

That's the best I can do with the knowledge I have! If anyone can offer advice on how to name substituents and where spacings in the name go you'd make me very happy!

Thanks

[swati]

  hello redfox
first of all, let me tell you certain rules breifly:-
1.) see the longest chain . Also this chain should should have all the functional groups.
2.) numbering should be done from that side from where sum of locants is minimum, that is , number given to substituents is minimum
3.) while writing the name, substituents should be written in alphabetical order e.g if in numbering we have chloro at 5th position & fluoro at 2nd position but while writing the name we will write 5-chloro-2-fluoro

correct name of
(a)is 4-chlorohept-5-en-1-yn-1-ol
according to rule(2) start numbering from right to left. You have to give number to OH group also.

(b) 5-ethyl-6,6,7,7,7-pentafluorohept-2-yne
here take the longest chain which has CF₂CF₃

(c) 2-ethoxypent-1,4-diene

(e) 5-chloro-1,1,1-trifluoro-2-methylhept-2,4-diene
here you will take the longest chain as one in which CF₃ is included.

[redfox]

Hi, thanks so much for your response - has really helped! Am just wondering why, in regards to B and E, you have chosen to use the CF groups as part of the main chain? And how would I name, for example, B if there was an extra carbon on the left end...would it be 1,1,2,2,2-pentafluoroethyl...? How would I fit in saying they're at position 5? Looks like it would be 5-1,1,2,2,2-pentafluoroethyl oct-2-yne tho I'm sure that's not correct! 

Cheers