Naming Help

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Isaac_Partida_1F
Posts: 10
Joined: Sat Jul 09, 2016 3:00 am

Naming Help

Postby Isaac_Partida_1F » Thu Mar 09, 2017 3:19 pm

When you have a cycloalkane and you have more than one substituent, how do you number when the all the corners of the molecule have a substituent. Is it alphabetical order?

Amy Ko 3C
Posts: 24
Joined: Sat Jul 09, 2016 3:00 am

Re: Naming Help

Postby Amy Ko 3C » Thu Mar 09, 2017 3:20 pm

It should be alphabetical with lowest number.
Also, the order of substituents should be taken into account (priority)

Sophia Rawson 1C
Posts: 12
Joined: Wed Sep 21, 2016 2:58 pm

Re: Naming Help

Postby Sophia Rawson 1C » Thu Mar 09, 2017 3:46 pm

Also, if you have more than two substituents you start with the substituents that are closest together. For example you would put 1,2 and 4 over putting 1 and 3,4

Erick_Hernandez_3L
Posts: 20
Joined: Sat Jul 09, 2016 3:00 am

Re: Naming Help

Postby Erick_Hernandez_3L » Thu Mar 09, 2017 11:03 pm

Do the numbers need to be lowest according to alphabetical order or is the alphabetical order only relevant when arranging the name of the molecule?

Natalie Rotstein 3J
Posts: 20
Joined: Wed Sep 21, 2016 2:59 pm

Re: Naming Help

Postby Natalie Rotstein 3J » Thu Mar 09, 2017 11:16 pm

Generally alphabetical order is just for the ordering of the name, not the numbering, but I think it might be good form to start with the 1 with the first named substitutent in the previously described situation where every single carbon had a substitutent attached.

nickrodgers
Posts: 10
Joined: Fri Jul 22, 2016 3:00 am

Re: Naming Help

Postby nickrodgers » Sat Mar 11, 2017 11:24 pm

If there are two substituents on the cycloalkane then the substituent with the earlier name alphabetically is given the first number.

If there are more than two substituents, then alphabetical naming is irrelevant to the numbering (only to the name) and the numbers are arranged so that the possible name with the lowest given numbers is chosen. The "in-between" numbers should be the lowest possible.

edhuang
Posts: 24
Joined: Wed Sep 21, 2016 2:58 pm

Re: Naming Help

Postby edhuang » Sun Mar 12, 2017 10:35 am

It is alphabetical, and whichever combination of numbers allows for the lowest numbers is the correct name.

Sean_Yue_1E
Posts: 9
Joined: Wed Nov 18, 2015 3:00 am
Been upvoted: 1 time

Re: Naming Help

Postby Sean_Yue_1E » Mon Mar 20, 2017 8:22 am

You can try the sum rule, organizing alphabetically doesn't always work for example "1,3 ethyl 2,2 dimethylcyclopentane" (unless you ignore the prefix). Generally I just remember it as bigger stuff first (with the exception of cyclo stuff)


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