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Naming Help

Posted: Thu Mar 09, 2017 3:19 pm
by Isaac_Partida_1F
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?

Re: Naming Help

Posted: Thu Mar 09, 2017 3:20 pm
by Amy Ko 3C
It should be alphabetical with lowest number.
Also, the order of substituents should be taken into account (priority)

Re: Naming Help

Posted: Thu Mar 09, 2017 3:46 pm
by Sophia Rawson 1C
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

Re: Naming Help

Posted: Thu Mar 09, 2017 11:03 pm
by Erick_Hernandez_3L
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?

Re: Naming Help

Posted: Thu Mar 09, 2017 11:16 pm
by Natalie Rotstein 3J
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.

Re: Naming Help

Posted: Sat Mar 11, 2017 11:24 pm
by nickrodgers
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.

Re: Naming Help

Posted: Sun Mar 12, 2017 10:35 am
by edhuang
It is alphabetical, and whichever combination of numbers allows for the lowest numbers is the correct name.

Re: Naming Help

Posted: Mon Mar 20, 2017 8:22 am
by Sean_Yue_1E
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)