nomenclature
4-ethyl-2methyl-1propylcyclohexane is the correct name. You are correct that the name should go in alphabetical order eg. ethyl, methyl propyl and the parent will be cyclohexane. The rule for numbering highly branched alkanes is called the "first point of difference" rule. In the two numbering schemes you use "4-ethyl-2methyl-1propylcyclohexane" or "1 ethyl 3 methyl 4 propylcyclohexane." Your first locant, in either case, is 1 (1 ethyl or 1 propyl) but looking at each numbering scheme, the second locant is either 2 or 3 (2methyl or 3methyl). The first point of difference rule means that even though both numbering schemes start at 1, the scheme that has the lowest number at it's first point of difference is the correct scheme. So 1, 2, 4 is correct while 1,3,4 is not. So numbering should be 1 propyl, 2 methyl, 4 ethyl and to keeep it alphabetic you get 4-ethyl-2methyl-1propylcyclohexane.
Hope this rule helps for any other similar problems,
bw800402
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