Naming with Substituents  [ENDORSED]

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Naming with Substituents

Postby Gina_Chiarolla_3C » Sat Mar 04, 2017 9:36 pm

How do you determine which substituent to start with while numbering. Is there a specific place to start the numbering?

Alex Dib 4H
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Re: Naming with Substituents  [ENDORSED]

Postby Alex Dib 4H » Sat Mar 04, 2017 11:07 pm

If I understand your question correctly, I think the numbering starts on the substituent that will yield the smallest combination of all substituent's numbers when added. For example, if you have two different possibilities for numbering a molecule's substituents which are (1, 3, and 4) or (1,2, and 4), you would choose the combination (1, 2, and 4) because this set is smaller overall, which means you start the numbering on whichever substituent was numbered "1" in that set. But you would not necessarily have to number them in order from lowest to highest when naming the full molecule, because alphabetical order of the substituents may be out of numerical order. Just maintain the association of substituent to its number when placing them in alphabetical order. Hope this makes sense

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