Abstract
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-1
H
-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,
1
H NMR,
13
C 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.