508184-36-9Relevant academic research and scientific papers
Microwave-assisted Vilsmeier-Haack synthesis of Pyrazole-4-carbaldehydes
Kumari, Poonam,Sood, Sumit,Kumar, Anil,Singh, Karan
, p. 796 - 804 (2019/11/28)
The synthesis of 4-formylpyrazoles using Vilsmeier-Haack reagent is a common protocol in pyrazole chemistry. An efficient microwave-assisted synthesis of 4-formylpyrazoles by employing Vilsmeier-Haack reagent (OPC-VH) derived from phthaloyl dichloride/dimethylformamide has been described. This method offers the advantages of operational simplicity, avoiding the use of POCl3 as toxic reagents and reuse of the by-product in the preparation of phthaloyl dichloride.
Microwave-assisted synthesis and biological evaluation of pyrazole-4-carbonitriles as antimicrobial agents
Kumar, Anil,Kumari, Poonam,Singh, Karan,Sood, Sumit,Yadav, Ajar Nath
, (2020/05/25)
An efficient microwave-assisted method of synthesis of pyrazole-4-carbonitriles has been developed. Condensation of pyrazole-4-carbaldehydes with hydroxylamine hydrochloride followed by reaction of the resulting oximes with the Vilsmeier-Haack reagent pre-formed from phthaloyl dichloride and dimethylformamide under microwave irradiation afforded the corresponding pyrazole-4-carbonitriles in 73percent to 91percent yield. The operational simplicity, avoidance of toxic reagents such as POCl3, shorter reaction time, higher yield compared to the classical version, easy work up, and the use of the by-product in the regeneration of phthaloyl dichloride are the advantages of this methodology. All the target compounds were tested for antimicrobial activity against Gram-positive bacteria Bacillus cereus and Staphylococcus aureus; Gram-negative bacteria Escherichia coli and Yersinia enterocolitica, and the fungal species Candida albicans.
