Efficient Synthesis and Antimicrobial Activities of Long Alkyl Chain Trifluoromethyl-1 H -pyrazol-1-(thio)carboxamides and Trifluoromethyl-1 H -pyrazol-1-yl-thiazoles

Journal of the Brazilian Chemical Society

article

Mello, Debora L. de¹  Malavolta, Juliana L.¹  Santos, Roberto C. V.²  Lopes, Leonardo Q. S.²  Moura, Sidnei³  Flores, Darlene C.⁴  Flores, Alex F. C.⁴ 

[1] Departamento de Química, Universidade Federal de Santa Maria;Embrapa Pecuária Sudeste;Instituto de Biotecnologia, Universidade de Caxias do Sul;Universidade Federal do Rio Grande

关键词: nitrogen heterocycles;    thiazoles;    pyrazoles;    antimicrobial activity;   

DOI  :  10.21577/0103-5053.20200241

学科分类：内科医学

来源: SciELO

【 摘 要 】

The synthesis of 3-alkyl-5-trifluoromethyl-1 H - pyrazole-1-carboxamides, 3-alkyl-5-trifluoromethyl-1 H -pyrazole-1-thiocarboxamides, and 2-(3-alkyl-5-trifluoromethyl-1 H -pyrazol-1-yl)-thiazoles derivatives are reported. [3 + 2] cyclocondensations for a series of long alkyl chain 1,1,1-trifluoro-4-methoxyalk-3-en-2-ones and semicarbazide or thiosemicarbazide were carried out in ethanol, an eco-friendly medium. The series of trifluoromethyl-1 H -pyrazol-1-yl-thiocarboxamide following a [3 + 2] cyclocondensation with 2-bromoacetophenone were converted into two series of 2-(3-alkyl-5-trifluoromethyl-1 H -pyrazol-1-yl)-thiazoles. Good yields (69-96%) of the isolated products were obtained. The structures of the new long alkyl chain 1 H -pyrazoles and 2-(1 H- pyrazol-1-yl)thiazoles were characterized using 1 H, 13 C, and 19 F nuclear magnetic resonance (NMR) spectroscopy and electrospray ionization tandem mass spectrometric (ESI MS/MS) data. Moreover, some of the products were evaluated for their antimicrobial activity against Gram-negative Escherichia coli American Type Culture Collection (ATCC) 35218, Salmonella enteritidis ATCC 13076, and Pseudomonas aeruginosa ATCC 15692; and Gram-positive Staphylococcus aureus ATCC 6538, methicillin resistant Staphylococcus aureus (MRSA clinical isolate), Streptococcus sp. (clinical isolate), and Candida albicans ATCC 14053 and Candida krusei ATCC 6258 fungi. All the tested 1 H -pyrazoles exhibited antibacterial and antifungal activities at the tested concentrations. The compounds from series 4 were found to be powerful against MRSA.

【 授权许可】

CC BY