Chapter 5, Problem 25PP

Interpretation Introduction

Interpretation:

The two chirality centres in chloramphenicol are to be identified and a three-dimensional formula for chloramphenicol is to be written.

Concept introduction:

The molecules or compounds which are non-superimposable or not identical with its mirror image are known as chiral molecules.

The pair of two mirror images which are non-identical are known as enantiomers and these are optically active.

The objects or molecules which are superimposable with their mirror images are achiral objects or molecules and these objects have a centre of symmetry or plane of symmetry.

The achiral compounds in which plane of symmetry is present internally and consists of chiral centres are known as meso compounds but they are optically inactive.

The stereoisomers which are non-superimposable on each other and not mirror images of each other are known as diastereomers.

Chiral molecules are capable of rotating plane polarized light

The molecules which are superimposable or identical with their mirror images are known as achiral molecules, and achiral molecules are not capable of rotating the plane-polarised light.

Plane of symmetry is the plane that bisects the molecule in two equal halves, such that they are mirror images of each other.

Compounds having plane of symmetry are usually achiral as they do not have different atoms around the central carbon atom.

The enantiomers, in which the path traced from the highest atomic number to the lowest atomic number is in an anticlockwise direction, are designated as $S$.

The enantiomers, in which the path traced from the highest atomic number to the lowest atomic number is in the clockwise direction, are designated as $R$.

The compounds or molecules which are superimposable with its mirror images are achiral objects or molecules and these objects have a centre of symmetry or plane of symmetry.