Why is this name not correct? #"7-ethyl-3,4,4,7-tetramethylheptane"#; what should it be?
The longest chain is
Counting from the left, we then land on a methyl (
#-"CH"_3#) group on carbon-3, two methyl groups on carbon-4, and one methyl group on carbon-7.
Counting from the right, we then land on a methyl (
#-"CH"_3#) group on carbon-3, two methyl groups on carbon-6, and one methyl group on carbon-7.
Part of the IUPAC naming is to minimize the carbon indexing, so counting from the left gives the correct carbon indexing. The last things we need to consider are
- how to denote duplicates
- how to denote how many duplicates of methyl groups we have.
- They are all methyl groups, so we don't have to worry about alphabetical ordering. We then list the carbon indices that the methyl groups are connected to.
- The prefix for four duplicate groups is "tetra".
So we should then get: