1. Stereochemistry of Natural
Products and their
applications
By: Muhammad Javaid Iqbal
Ali Riaz
Ali Ziab

2. Stereochemical isomers are molecules, which have
the same chemical formula and bond connectivity
but different relative arrangement in three
dimensional space.it is also known as 3D chemistry.
Stereochemical isomers:

3. Natural Products
 Natural product is a chemical compound or
substance produced by a living organism, that is
found in nature. Natural products include any
substance produced by life.
 Natural products can also be prepared by chemical
synthesis and have played a central role in the
development of the field of organic chemistry by
providing challenging synthetic targets.
 The term natural product has also been extended
for commercial purposes to refer to cosmetics,
dietary supplements, and foods produced from
natural sources without added artificial ingredients.

4. Natural products are classified into several categories , one of
them is:
Natural Product
(secondary metabolites)natural products synthesized
mainly by bacteria, fungi and plants.
Terpenoids Alkaloids Steroids
Phenolic
compounds
Menthol Caffeine Cholesterol Phenols

5. Chiral
ity
Chiral objects are non-superimposable mirror
images of each other. Achiral objects, on the
other hand, are easily superimposable on each
other.
Cholesterol
Chiral carbon must have four different groups. For
example, cholesterol have eight chiral centres.

6. Optical Activity
 Each enantiomer of a chiral structure reacts
differently with polarized light.
 Polarized light is light were only one plane of
polarization is chosen by a polarization filter.
 When this light is travelling through a chiral
substance, the plane of rotation will change.
 Here in this example,(-).carvone has an angle
of rotation of -72°,(+).carvone one of +72 °.

8. (limonene) the compound which gives different taste to lemon
and orange are examples of stereochemical isomers.

9. Enantiomer
If a molecule is non-superimposable on its mirror
image, then the molecule is said to have
enantiomeric relationship with its mirror image
molecule.
Terpene
Linalool has two enantiomeric forms which are
both found in nature.
(R)-(-)-linalool enantiomer is responsible for the
fragrant scent in lavender and sweet basil.
(S)-(+)-linalool enantiomer is largely found in
essential oils of coriander seed and sweet orange
flowers.

11. (In 1884, By Louis Pasteur) found two of the four
possible stereoisomers (R,R)- and (S,S)- are
enantiomers but the 3rd and 4th isomers called a
meso compound due to (plane of symmetry)
Meso is (optically inactive) diastereomers of chiral
stereoisomers.
Study of Tartaric acid

12. Study of Tartaric acid

13. Diastereomerism occurs if both molecules contain two or more chiral
centers, but if only one of the chiral centers in each molecule is different
than the other, then the two molecules are diastereoisomer.
Diastereomer:
The meso form of tartaric acid is a diastereomer of the other forms.

14. References:
• Introduction to Natural Products and Medicinal
Chemistry, David LEMIN. Chiba University 2005
• Chemistry of Plant Natural Products, Sunil Kumar
Talapatra · Bani Talapatra
• Consumer Chemistry, A Brief History of Natural
Products and Organic Chemistry Chapter 6
• Webster's Revised Unabridged Dictionary (1913).
"Natural product". Free Online Dictionary and C. & G.
Merriam Co. A chemical substance produced by a
living organism; - a term used commonly in reference
to chemical substances found in nature that have
distinctive pharmacological effects. Such a substance is

15. Thank You
Any Questions?