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Ph.D.
(Science)
SYNTHESIS AND CHARACTERISATION OF DIVERSE HETEROCYCLIC
SCAFFOLDS AND THEIR APPLICATIONS

Ph.D. Scholar : Patel Shwetaben Amichandbhai
Research Supervisor : Dr. Hasit V. Vaghani

Regi. No.: 19276461003
Abstract :
The five chapters that make up the current work are introduced by a discussion of
heterocyclic chemistry and medicinal importance of heterocyclic compounds. This
chapter also covered the introduction of green chemistry, green chemistry tools used in
the synthesis of target molecules, trends in green chemistry, water as a green solvent,
synthesis assisted by water, Multicomponent reactions, History and classification of
MCRs, Different approach in MCRs, Introduction of Sonochemistry, History and
fundamental of sonochemistry, sonochemistry reactions, sites of sonochemistry
reactions and ultrasonic cleaning bath.

The present chapter two consists of conventional and microwave assisted multi-step
synthesis of 1,3,4-oxadiazole derivatives and their spectral characterization. 1,3,4-
oxadiazole based chalcone derivatives are synthesized via four successive steps. Step 1:
Synthesis of 5-(pyridin-4-yl)-1,3,4-oxadiazole-2-thiol, Step 2: Synthesis of N-(4-
acetylphenyl)-2-chloroacetamide, Step 3: Synthesis of N-(4-acetylphenyl)-2-((5-(pyridine-4-
yl)-1,3,4-oxadiazol-2-yl) thio) acetamide and Step 4: Synthesis of (E)-N-(4-(4-phenylbut-3-
enoyl)phenyl)-2-((5-(pyridine-4-yl)-1,3,4-oxadiazol-2-yl)thio)acetamide which is final
derivative of this reaction.

In chapter three focus the synthesis of new 1,8-naphthyridine derivatives using a green
and environmentally friendly method. A one-pot multicomponent reaction was performed
using water as a solvent and ultrasonic irradiation. The method is simple, clean, safe and
environmentally friendly. The synthesized compounds were confirmed using various
spectroscopic techniques like FT-IR, Mass, 1H NMR and 13C NMR. The results showed
that optimization studies were successful and a comparison was made between the
green and conventional methos.

Furthermore, chapters four and five focus the one-pot, multi-component synthesis of
heterocyclic compounds containing nitrogen and oxygen, which was accomplished using
ultrasonic irradiation and morpholine as a catalyst in an aqueous environment. The
synthesized derivatives were confirmed by IR, Mass, 1H NMR, 13C NMR and their
spectral characterization are furnished here. Water as green solvent is used in the
synthesis. The ultrasound assisted synthesis and characterization of pyrano[2,3-c]

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