Knorr Pyrazole Synthesis (M. Pharm)

M. Pharm. (Pharmaceutical Chemistry)

1. Knorr Pyrazole Synthesis Presented by: Mohd Shafeeque M. Pharm. 1 st Sem. (Pharm. Chemistry) Jamia Hamdard

2. The Knorr pyrazole synthesis is an organic reaction used to convert a hydrazine or its derivatives and a 1,3-dicarbonyl compound to a pyrazole using an acid catalyst

3. MECHANISM

4. The mechanism begins with an acid catalyzed imine formation, where in the case of hydrazine derivatives the attack can happen on either carbonyl carbon and result in two possible products. The other nitrogen of the hydrazine derivative then attacks the other carbonyl group which has also been protonated by the acid and forms a second imine group. This diimine compound gets deprotonated to regenerate the acid catalyst and provide the final pyrazole product.

5. APPLICATION: Used for the synthesis of metal chelate, photographic dyes, herbicides and biologically active compounds.

6. ANTIPYRINE 1,5-Dimethyl-2-phenylpyrazole-3-one

7. Mechanism of Action: Antipyrine is thought to act primarily in the CNS, increasing the pain threshold by inhibiting both isoforms of cyclooxygenase, COX-1, COX-2, and COX-3 enzymes involved in prostaglandin (PG) synthesis.

8. Synthesis of Antipyrine: EAA Phenylhydrazine

9. CELECOXIB 4-[5-(4-methylphenyl)-3-(trifluoromethyl)pyrazol-1-yl]benzene-1-sulfonamide

10. Mechanism of Action: Inhibition of prostaglandin synthesis, primarily via inhibition of cyclooxygenase-2 (COX-2), and at therapeutic concentration in humans, Celecoxib does not inhibit the cyclooxygenase-1 (COX-1) isoenzyme.

11. Synthesis of Celecoxib:

12. METAMIZOLE SODIUM [(1,5-dimethyl-3-oxo-2-phenylpyrazol-4-yl)-methylamino] methanesulfonic acid

13. Mechanism of Action: Metamizole is a pro-drug, which spontaneously breaks down after oral administration to structurally related pyrazolone compounds. Apart from its analgesic effect, the medication is an antipyretic and spasmolytic agent. The mechanism responsible for the analgesic effect is a complex one, and most probably rests on the inhibition of a central cyclooxygenase-3 and activation of the opioidergic system and cannabinoid system.

14. Synthesis of Metamizole Sodium:

15. THANK YOU