α,α‐Dibromoketone precursors in the synthesis of some new thiazole derivatives: Thiazol‐2‐yl hydrazonobutanoates, thiazol‐2‐yl pyrazole‐4‐carboxylates and acids

• Published in: Journal of heterocyclic chemistry Vol. 57; no. 5; pp. 2173 - 2183
• Main Authors: Kiran, Vijay, Joshi, Radhika, Pundeer, Rashmi
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Inc 01-05-2020; Wiley Subscription Services, Inc
• Subjects: Carboxylates; Coliforms; E coli; Esters; Fungicides; Precursors; Pseudomonas aeruginosa; Pyrazole; Synthesis
• ISSN: 0022-152X; 1943-5193
• DOI: 10.1002/jhet.3937

In the present study, α,α‐dibromoacetophenones are used as efficient precursors for the facile synthesis of several new hydrazonothiazoles, ethyl 3‐((4‐arylthiazol‐2‐yl)hydrazono)butanoates, which undergo Vilsmeier‐Haack cyclization to obtain thiazolylpyrazole esters, ethyl 3‐methyl‐1‐(4‐arylthiazol‐2‐yl)‐1H‐pyrazole‐4‐carbxylates, basic hydrolysis of which gives the corresponding acids, 3‐methyl‐1‐(4‐arylthiazol‐2‐yl)‐1H‐pyrazole‐4‐carbxylic acids. All these compounds are tested for antibacterial activity against Gram‐positive bacteria Staphylococcus aureus and Bacillus subtilis; Gram‐negative bacteria Escherichia coli and Pseudomonas aeruginosa and antifungal activity against Saccharomyces cerevisiae and Candida albicans.