Organic Question

[hashemiaan]

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I have a question on absolute configuration.
so if you could draw this molecule and tell me if it's S or R.

it's acid so draw COOH on the right hand side and then attach to taht we have C and attach to taht CH3(which is comint toward us) and NH2 going inside.

What i did was NH2 is 1 and COOH is 2 and 3 is CH3. and I figured it's S but since H is lower and it's supposed to go inward I switched it to R. so I thinks it's R but the answer is S. i don't get it

Thanks

 

[PreDent2009]

From how your explaining it, it seems like it is in a tetrahedral arrangement. If the methyl group is coming towards us and is wedged, while the amine group is dashed, then it is in fact S, since the #4 group has to be going back. Is the amine group dashed or is the hydrogen dashed? It will make the difference between R and S.