nomenclature question

[anonymuz]

Advertisement - Members don't see this ad

3-ethyl-1,1-dimethyl-4-propylcyclohexane

how come you dont name the propyl group 1, ethyl group 2 and the dimethyl's 4?

thanks

 

[DQLEUCD]

3-ethyl-1,1-dimethyl-4-propylcyclohexane

how come you dont name the propyl group 1, ethyl group 2 and the dimethyl's 4?

thanks

You need the lowest combinations of substituants. Lets say you have the option of 1,2,4 or naming it in reverse 2,4,5.. 1,2,4 will always win because you have 1 which trumps 2 and etc.. I believe that's what your asking, correct?

 

[Baylor2011]

Because you need the lowest total number when numbering substituents.. let me explain

If you numbered 1 from the methyl groups to 4 w/ propyl.. you have 1 (CH3) + 1(CH3) + 3 (Eth) + 4 (Prop) = 9

If you numbered from 1 being propyl to 4 being methyls you'd have 1 (prop) + 2 (eth) + 4 (CH3) + 4 (CH3) = 11

9 is less than 11, so that numbering is preferred