Solvent free Montmorillonite
K-10 Clay catalyzed synthesis and Structure elucidation of pyrazoloimidazole-2-thione
Derivatives
Jaiswal Shalini
Res. J. Chem. Environ.; Vol. 29(4); 86-93;
doi: https://doi.org/10.25303/294rjce086093; (2025)
Abstract
The pharmaceutical industry faces challenges such as the use of toxic solvents,
excessive use of energy, waste generation and the implementation of conventional
procedures that do not adhere to green chemistry principles. In the present study,
we report the prompt mineral (Montmorillonite K-10 clay) triggered cyclo-condensation
of chloroacetic acid with arylthiourea subsequently followed by Knoevenagel condensation
with aromatic aldehyde in combination with sodium acetate without solvents microwave
irradiation results in 3-aryl-5-benzylideno-2-thiohydantoins 4(a-l).
The substances 4 (a-l) with hydrazine hydrate in glacial acetic acid offered the
intermediate acetyl hydrazone of 4(a-l) which on cyclo-isomerization under reaction
conditions gave 1,8-diaryl-4,8-dihydro-1-acetylpyrazolo[3,4-c] imidazole-2-thiones
5 (a-l).
