Title:Microwave-assisted Synthetic Scheme of Novel Schiff Base Congeners of
Pyrimidine Nuclei by Using Water as Solvent: A Green Approach to Synthesis
Volume: 9
Issue: 1
Author(s): Dipanjan Karati, Kakasaheb Ramoo Mahadik and Dileep Kumar*
Affiliation:
- Department of Pharmaceutical Chemistry, Poona College of Pharmacy, Bharati Vidyapeeth (Deemed to be University)
Erandwane, Pune- 411038, Maharashtra, India
Keywords:
Pyrimidine nucleus, schiff base, microwave-assisted synthesis, one-pot synthesis, multicomponent reactions, 4- (benzylidene amino)-6-phenylpyrimidine-5-carbonitrile.
Abstract:
Aim: The research work aims to develop a sustainable microwave-assisted scheme for the
synthesis of 4-(benzylidene amino)-6-phenylpyrimidine-5-carbonitrile congeners.
Background: 4-(benzylidene amino)-6-phenylpyrimidine-5-carbonitrile scaffolds are novel molecules
having various pharmacological activities, such as neurodegenerative, antimicrobial, and anticancer.
Schiff base congeners are considered efficient pharmacophores for research. These activities are due to
the presence of azomethine (CH=N) group in the Schiff base compounds.
Objective: The aim of the study was to synthesise different novel Schiff base scaffolds of pyrimidine
nuclei by green chemistry in good yield.
Methods: The 4-(benzylidene amino)-6-phenylpyrimidine-5-carbonitrile scaffolds were prepared by
two-step reactions. Both steps were microwave-assisted. The first step was to synthesize 4-amino-6-
phenylpyrimidine-5-carbonitrile as an intermediate compound. This compound was synthesized by
using benzaldehyde, malononitrile and formamidine hydrochloride. The reaction conditions are as
follows: temperature- 101°C, pressure- 300W, time- 50 min.
The final Schiff base congeners were obtained by reacting them with various aromatic aldehydes in the
second step. The yield, reaction condition, and time consumption were all very acceptable for the green
synthetic methods rather than the conventional schemes.
Results: Microwave-assisted method was more efficient. The reactions were less time-consuming, and
the overall yield of the all-synthesized compounds was in the range of 72-81%. The synthesized congeners
were characterized by different spectroscopic methods. The main functional group, azomethine,
was considered by the IR peak at 1611 cm-1 wavelength.
Conclusion: This microwave-assisted synthetic method thus emerges as more eco-friendly due to a
much-reduced usage of organic solvents, leading to less harmful residues. Using this scheme, we synthesized
different Schiff base congeners with satisfactory chemical yields.