[euge.hcbb]

Hi everybody,
i'm italian student, i tried to explain the exercise on a italian forum but no one replied to my request, so i try to ask here and hope for help..sorry if will be some language mistakes.

This is the compound i must study:
http://imgur.com/a/VG2Me

i have to:
1. write the correct name with IUPAC rules
2. Find and write the geometric structure of the functional groups
3. Find the confirurational and conformational stereoisomers, indicate the number of them and write che right configuration

Resolution:
1. The name of compound is 4-amminopent-2-henoic acid

2. Geometric structure:
- Aminic group
N has two free electrons on the top with cloud and 3 bonds with C4 and two hydrogens, this 3 bonds are 108° one to each other.

-Carbossilic group
Is planar, the C has a double bond with an O and a bond with a OH. All this bonds are 120° one to each other

- Double bond in C2 is planar and the 4 substituents are 120° one to each other

- C4 is chiral and has a tetrahedral structure where the 4 bonds are 109.5° one to each other.

3. This is the problematic part:
There is conformation isomerism with C4 and C5, and here i can write the carbon-carbon bond with Newman projections where the most stable conformation is the staggered one.

There is a chiral carbon in C4 that have 4 different substituent so is a configurational isomer and the configuration is S. 
I have drawn the configuration here http://imgur.com/a/lXHN2
If want i could change just two bonds in this C and will be a change of configuration in R, so i can tell that are optical isomery here.

And there is also configurational isomery in C2 anc C3, becouse double bond.
I supposed this should be a Z configuration.

Now, my doubt is about the two configurations i founded, i never seen a S,Z configuration together in the name of a compound..so i ask someone please tell if and where i was wrong in the develop of the exercise, and explain me why.
What will be the right name of the compound with the right configuration?

Thanks!

[sjb]

I think your analysis is mostly right, some typos if this is meant to be English.

The bond angles won't be exactly as you have described but the order (largest to smallest) is fine.

Yes, you can have S and Z (and S & E, R & Z, R & E) in one name. That's not an issue.

I'm not convinced you actually have exactly the isomer you have described as there is no stereochemistry drawn. So for the name I wouldn't include them (the double bond is also implied by the pent-2-enoic acid part of the name.