Synthesis of Some Novel Heterocyclic and Schiff Base Derivatives as Antimicrobial Agents

Abstract

Treatment of 2,3-diaryloxirane-2,3-dicarbonitriles 1a-c with different nitrogen nucleophiles, e.g., hydrazine, methyl hydrazine, phenyl hydrazine, hydroxylamine, thiosemicarbazide, and/or 2-amino-5-phenyl-1,3,4-thiadiazole, afforded pyrazole, isoxazole, pyrrolotriazine, imidazolothiadiazole derivatives 2-5, respectively. Reacting pyrazoles 2a-c with aromatic aldehydes and/or methyl glycinate produced Schiff's bases 7a-d and pyrazolo[3,4-b]-pyrazinone derivative 8, respectively. Treating 7 with ammonium acetate and/or hydrazine hydrate, furnished the imidazolopyrazole and pyrazolotriazine derivatives 9 and 10, respectively. Reaction of 8 with chloroacetic acid and/or diethyl malonate gave tricyclic compound 11 and triketone 12, respectively. On the other hand, compound 1 was reacted with active methylene precursors, e.g., acetylacetone and/or cyclopentanone producing adducts 14a,b which upon fusion with ammonium acetate furnished the 3-pyridone derivatives 15a,b, respectively. Some of newly synthesized compounds were screened for activity against bacterial and fungal strains and most of the newly synthesized compounds showed high antimicrobial activities. The structures of the new compounds were elucidated using IR, 1 H-NMR, 13 C-NMR and mass spectroscopy.

A Concise Review on the Synthesis and Reactions of Pyrazolopyrazine Heterocycles

“…Reaction of 3‐amino‐5,5‐(4‐tolyl)‐1 H ‐pyrazol‐4(5 H )‐ones (89) with methyl glycinate in boiling ethanol furnished 3,3‐di(4‐tolyl)‐2,3‐dihydro‐ 1H ‐pyrazolo[4,3‐ b ]pyrazin‐6( 7H )‐one (90) (Scheme ) .…”

Synthesis of Novel Pyrazole Derivatives as Antineoplastic Agent

“…The different kinds of electrophilic center in 2,3‐diaryloxirane‐2,3‐dicarbonitrile 1 are allowed to react with simply bi‐nucleophiles to afford the new heterocyclic compounds; they are dependent upon the type of nucleophile. 2,3‐Diaryloxirane‐2,3‐dicarbonitrile 1 is allowed to react with hydrazine precursors, such as hydrazine hydrate, methylhydrazine, and phenylhydrazine to afford the corresponding pyrazole derivative 2 that proposed the mechanism of pyrazole product 2 as shown in Scheme .…”

Studies on Coordination Behaviour of a Polydentate Schiff Base in Presence of Dimethyl Sulphoxide on Rare Earth Metal Ions

“…From literature, it is found that the schiff bases derived from heterocyclic aldehydes such as furan-2-aldehyde, thiophene and pyridine-2-aldehyde can act as potential ligands and show considerable antibacterial activity [10][11][12][13] . The antibacterial property of the ligand P 2 CAAP and the complex [Ln(P 2 CAAP) (DMS)(NO 3 ) 3 ] were studied at different concentrations (0.01,0.02,0.03,0.04 and…”