Synthesis, characterization and antimicrobial activity of certain novel aryl hydrazone pyrazoline-5-ones containing thiazole moiety

4-Nitropyrazolin-5-ones as Readily Available Fungicides of the Novel Structural Type for Crop Protection: Atom-Efficient Scalable Synthesis and Key Structural Features Responsible for Activity

The development of new types of fungicides for agriculture and medicine is highly desirable due to the uprising fungal resistance against commonly used compounds. Herein, 4-substituted-4-nitropyrazolin-5-ones (nitropyrazolones) were proposed as highly active fungicides of the novel structural type. The first scalable and practical method for the nitropyrazolone synthesis was proposed, which is atom-efficient, is applicable for the multigram scale synthesis, and allows for production of a wide variety of nitropyrazolones with high yields and purity. The synthesized compounds demonstrated high fungicidal activity against the broad spectrum of phytopathogenic fungi (Venturia inaequalis, Rhizoctonia solani, Fusarium oxysporum, Fusarium moniliforme, Bipolaris sorokiniana, and Sclerotinia sclerotiorum). Their mycelium growth inhibiting activity was comparable or superior to that of kresoxim-methyl. In vitro activity against Staphyloccocus aureus, Candida albicans, and Aspergillus niger revealed that nitropyrazolones are promising candidates against human pathogens. The key factors for the manifestation of high fungicidal activity were established to be an aromatic substituent on the N1 atom and small substituents, such as methyl, at the C3 and C4 positions of the pyrazolone ring.

Synthesis and antimicrobial evaluation of certain novel thiazoles

PURPOSE

This article makes an attempt to synthesize certain compounds containing thiazole and imidazole moieties and screen for the antimicrobial properties.

METHODS

The novel compounds synthesized were characterized by elemental analysis, IR and (1)HNMR spectral data. The antimicrobial activity of novel compounds was evaluated by cup plate method.

RESULTS

The compound p-t showed more antibacterial activity than that of the standard. p-hp and p-as showed considerable antibacterial activity. p-t demonstrated higher antifungal activity than that of the standard while p-hp and p-as showed considerable antifungal activity.

CONCLUSION

The antimicrobial activity studies were conducted on certain selected bacteria and fungi. In each case antimicrobial activity of the compounds was compared with that of standards. p-t, p-hp, p-np, p-cp, p-ts and p-as showed considerable antimicrobial activity.