Medicinal chemistry introduction, Study notes of Organic Chemistry

Download Medicinal chemistry introduction and more Study notes Organic Chemistry in PDF only on Docsity!

History and development of medicinal chemistry

Dr. Gopal Krishna Padhy

Introduction to medicinal chemistry 

Medicinal chemistry and pharmaceutical chemistry are disciplines of chemistry, especially synthetic organic chemistry, pharmacology andother biological specialization, where they are involved with design,chemical synthesis and development of pharmaceutical agents, or bio-active molecules (drugs).

Medicinal chemistry in its most common practice—focus on synthetic organic chemistry, natural products and computational chemistry inclose combination with chemical biology, enzymology and structuralbiology, together aiming at the discovery and development of newtherapeutic agents.

General anesthetics like diethyl ether (1842), nitrous oxide (1845) andchloroform (1847)) where introduced in surgery from 1842 onwards.Antiseptics such as iodine (1839) and phenol (1860) also made animportant contribution to the success of surgery. The hypnotic activityof chloral (trichloroethanal) (1869) was also reported.

Although the use of willow bark as a pain-killer was known to theherbalists, the analgesic activity of its constituent salicylic acid wasdiscovered

in

the

1870s.

p-Hydroxyacetanilide

(paracetamol)

and

phenacetin (1886) were also recognized as pain-killers. Acetylation ofsalicylic acid to reduce its deleterious effect on the stomach led to theintroduction of aspirin in 1899. However its mode of action was notestablished until 1971.

Paracetamol

O

O

HN

Phenacetin

Aspirin

Cocaine

2

Benzocaine

Procaine



20th century saw the recognition of vitamin deficiency diseases and theelucidation of the structure of various vitamins. Subsequently synthetic anti-malarials

such

as

pamaquine

(1926),

mepacrine

(1932)

and

later

chloroquine were introduced as quinine replacements.



A number of developments took place in structures of various vitamin andstructures

of

various

vitamin

the

1960s,

which

changed

medicinal

chemistry.



It was found that a drug, thalidomide which had been introduced as a

sedative, when used by pregnant women, led to the birth of deformedchildren

(S isomer). The consequences of this teratogenic effect

brought

about

a

major

tightening

of

the

regulations

regarding

drug

registration and the safety of medicines.



Secondly

in

1964

Hansch

published

correlations

between

substituent

effects (Hammett parameters) and the biological activity of some aromaticcompounds. These QSAR began to provide a framework for the systematicdevelopment of drugs and for decisions to be made in the planning of aresearch programme.