How can I convert Newman projection for the staggered and eclipsed conformations of 2-methylpentane for rotation about the #C2-C3# bond to bond line notation?
Here are the six Newman projections for the staggered and eclipsed conformations of 2-methylpentane.
I doesn't matter which one we choose, so let's start with Structure A.
Note that there is a carbon atom at the centre of the "Y" in the middle of the circle, and there is also a "hidden" carbon behind the circle.
We hunt for the longest continuous chain of carbon atoms.
It goes from one of the methyl groups in the front, to C-2 in the middle of the Y, to the hidden C-3, and then to the two carbons of the ethyl group.
That makes a 5-carbon chain.
Now we look for substituents.
One of the methyl groups is part of the main chain, but the other methyl group is a substituent on C-2.
There are no other substituents.
So we have 2-methylpentane.
The bond-line structure consists of a zig-zag line of five carbon atoms with a methyl group attached to C-2.