Naming ethers: priority of alkyl substituent and ethoxy subsitutent

[Sunwoo Bae]

Homework Statement

Naming the given structures

Relevant Equations

None

When there is both alkyl substituent and ethoxy substituent in a single molecule, which one should be prioritized when numbering your base carbon chains?
I am confused because the first structure below seems to have numbered the carbon attached to ethyl as the first carbon, while the second structure seem to give carbon attached to ethoxy group the lowest carbon number.

Thanks for your help!

 

[docnet]

Homework Statement:: Naming the given structures
Relevant Equations:: None

When there is both alkyl substituent and ethoxy substituent in a single molecule, which one should be prioritized when numbering your base carbon chains?
I am confused because the first structure below seems to have numbered the carbon attached to ethyl as the first carbon, while the second structure seem to give carbon attached to ethoxy group the lowest carbon number.

Thanks for your help!

View attachment 287488View attachment 287489

How to name organic compounds using the IUPAC rules...

3. Number the carbons of the parent chain from the end that gives the substituents the lowest numbers. When compairing a series of numbers, the series that is the "lowest" is the one which contains the lowest number at the occasion of the first difference. If two or more side chains are in equivalent positions, assign the lowest number to the one which will come first in the name.

source: http://www.chem.uiuc.edu/GenChemReferences/nomenclature_rules.html