00:01
I've translated the ball and stick model to a skeletal structure.
00:05
The stereo centers are drawn here in red.
00:09
Keep in mind a stereo center must have four different things attached to it to be a chiral center, to be a tetrahedral chyl center.
00:18
So let's start with this center, figure out of its r .s.
00:22
Designating by highest priority, oxygen wins because it has the greatest molecular weight.
00:26
Then the benzene ring because this carbon is attached to it has three four bonds total to carbon whereas this one only has two bonds to carbon and two bonds to hydrogen and carbon has a higher molecular weight so and the lowest priority is a hydrogen that's implied on this carbon which is coming straight out towards us so the way it's drawn this looks like this would be r but keep in mind the lowest priority is coming straight towards you so you have to invert it meaning that this stereo center is s.
00:56
For the next one, here we have three carbons to compare, and you want to look at what is attached directly to those carbons.
01:04
This carbon is attached, has two bonds to oxygen, one nitrogen, one to carbon.
01:10
The other carbons are only attached to other carbons, so this has the highest priority.
01:15
Then this carbon, because it is attached to one carb, two carbons, a hydrogen and a nitrogen, nitrogen is higher priority than carbon or hydrogen, so it gets priority number two...