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Here the choice lies between two possible main chains of equal length, each containing six side chains in the same positions. Listing in increasing order, the number of carbon atoms in the several side chains of the first choice as shown and of the alternate second choice result as follows:

first choice 1,1,1,2,8,8
second choice 1,1,1,1,8,9
The expression, "the greatest number of carbon atoms in the smaller side chains", is taken to mean the largest side chain at the first point of difference when the size of the side chains is examined step by step. Thus, the selection in this case is made at the fourth step where 2 is greater than 1.

This HTML reproduction of Sections A, B and C of IUPAC "Blue Book" is as close as possible to the published version [see Nomenclature of Organic Chemistry, Sections A, B, C, D, E, F, and H, Pergamon Press, Oxford, 1979. Copyright 1979 IUPAC.] If you need to cite these rules please quote this reference as their source.

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