Chapter 25, Problem 43PP

(a)

Interpretation Introduction

Interpretation:

The two amino acids which has two chiral centers need to be found out and the configuration need to be assigned.

Concept introduction:

Amino acids are compounds with difuntional group, amine and carboxylic acid group.  There are about twenty naturally occurring amino acids.  Each amino acid has atleast one chiral carbon in it except glycine.  A chiral carbon is the carbon which is bonded to four different groups.

To find : To find the amino acids that has two chiral centers

(b)

Interpretation Introduction

Interpretation:

The two amino acids which has two chiral centers need to be found out and the configuration need to be assigned.

Concept introduction:

Cahn-Ingold-Prelog convention can be applied to derive the configuration of the chirality center depending upon the priority of the groups attached.  The atom which has higher atomic number gets the higher priority followed by the others atoms.  After assigning the priority and numbering, if the sequence 1-2-3 is in clockwise rotation the configuration is assigned as “R” and if it is in counterclockwise then it is assigned “S”.

To find : To find the configuration of the two chiral centers in the amino acids possessing two chiral centers