Page 52 - Pharmaceutical Organic Chemmistry-3 (Theoritical book) 24-25
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Clinical Pharmacy PharmD - 2024/2025 Level 2 Pharmaceutical Organic Chemistry-3 (PC 305)
Pyrazoles
Synthesis
1) From 1,3-dicarbonyl compounds:
Condensation of 1,3-dicarbonyl compounds with hydrazine or its derivatives gives
pyrazoles.
Properties
o
• Pyrazole is a colorless solid, mp 70 .
• It is the only one of the trio of 1,2-azoles, (pyrazole, isoxazole and isothiazole), to
be solid at room temperature.
• This might be attributed to intermolecular hydrogen bonding which results in a
dimer formation only in case of pyrazole.
H N
N
N pyrazole dimer
N H
Chemical reactions
a. Electrophilic substitution reactions
Occurs at the 4-position
