S and R determination (orgo help)

[scrubswannabe]

(S)-2-Aminopropanoic acid

can someone explain to me why this molecule is S and not R?

I couldn;t cut the picture out of my powerpoint slides but it looks like this

Ch3 - C - COOH
l
NH2
the C - NH2 bond is pointing at us. and the NH2 isnt attached to the CH3 but the C

Thanks for your time.

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[Kaustikos]

Well, I don't know about anyone else, but when I draw out the fischer projection for this compound, I get the S conformation, not the R.

The NH3 is pointing out? What do you mean by that? How are the C and COOH bonds relative to the central C spatially? Where is the H in this orientation? If I just look at it from the compound, the CH3 and COOH are sticking out and the NH3 and H are sticking into the background. If you arrange it from there, you get the S configuration.

 

[iA-MD2013]

Well, I don't know about anyone else, but when I draw out the fischer projection for this compound, I get the S conformation, not the R.

The NH3 is pointing out? What do you mean by that? How are the C and COOH bonds relative to the central C spatially? Where is the H in this orientation? If I just look at it from the compound, the CH3 and COOH are sticking out and the NH3 and H are sticking into the background. If you arrange it from there, you get the S configuration.

That looks like its S to me too.

 

[Phlame217]

Its s, not r:

Draw the newmans, the hydrogen is in the back as shown.
Label the groups 1, 2, 3, and 4 respectivly and trace a circle.
The circle goes counterclockwise and the 4 group is already in the back so it stays that way and so CCW = S configuration.

forgive my drawing, its my attempt with paint lol.