5-Chloro-3-methyl-1-phenylpyrazole-4-carbonitrile
3 was reacted with selenium in the presence of sodium
borohydride and chloroacetamide to afford selanyl acetamide
5, which underwent Thorpe–Ziegler cyclization upon heating
with sodium ethoxide to give the novel synthesized 4-amino-
3-methyl-1-phenyl-1H-selenolo[2,3-c]pyrazole-5-carboxamide
compound (6). The latter compound was used as a
versatile precursor for synthesis of other heterocyclic rings,
namely pyrimidine, imidazopyrimidine and thiadiazinopyrimidine
fused to selenolo[2,3-c]pyrazole moiety.
The newly synthesized compounds and their derivatives
were characterized by elemental and spectral analysis (IR,
1H NMR, 13C NMR and mass spectrometric analyses).
Furthermore, some of these synthesized compounds were
screened against various pathogenic bacterial and fungal
strains. The results demonstrate that most of the synthesized
compounds possess a significant antibacterial activity
against gram-positive and gram-negative bacteria. Also,
some of these compounds showed a remarkable antifungal
activity, especially Candida albicans. On the other hand,
some of the synthesized compounds possess high anti-inflammatory
activity using carrageenan-induced rat paw
edema assay compared with indomethacin.
Graphical Abstract The present work discussed synthesis
of new selenolo[2,3-c]pyrazoles fused to other heterocyclic
rings, namely pyrimidine, imidazopyrimidine and thiadiazinopyrimidine.
Some of the synthesized compounds
showed remarkable antibacterial, antifungal and anti-inflammatory
activities.