Synthesis in Water and Antimicrobial Activity of 5-Trichloromethyl-4,5-dihydroisoxazoles
作者:Alex F. C. Flores、Luciana A. Piovesan、Alynne A. Souto、Mariano A. Pereira、Marcos A. P. Martins、Tatiane L. Balliano、Givanildo S. da Silva
DOI:10.1080/00397911.2012.706349
日期:2013.9.2
Two series of 5-trichloromethylisoxazoles were synthesized from the cyclocondensation of 1,1,1-trichloro-4-methoxy-3-alken-2-ones [Cl3CC(O)C(R-2)=C(R-1)OMe, where R-1=H, Me, Et, Pr, iso-Pr, cyclo-Pr, Bu, terc-Bu, CH2Br, CHBr2, CH(Me)SMe, (CH2)(2)Ph, and Ph, and R-2=H; R-1=H and R-2=Me and Et; R-1 and R-2=-(CH2)(4)- and -(CH2)(5)-; and R-1=Et and Ph and R-2=Me] with hydroxylamine hydrochloride through a rapid one-pot reaction in water. The 5-trichloromethyl-4,5-dihydroisoxazoles were aromatized by reaction with concentrated sulfuric acid to obtain the respective 5-trichloromethylisoxazoles. Their structures were confirmed by elemental analysis, H-1/C-13 nuclear magnetic resonance, and electron impact mass spectroscopy. Crystal structure analysis for 5-triclhoromethyl-5-hydroxy-3-propyl-4,5-dihydroisoxazole (2d) and 5-trichloromethyl-5-hydroxy-3,4-hexamethylene-4,5-dihydroisoxazole (2o) is presented. The antimicrobial activities of the 5-trichloromethyl-4,5-dihydroisoxazole derivatives were examined using the standard twofold dilution method against Gram-positive bacteria (Staphylococcus aureus), Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa), and yeasts (Candida spp. and Cryptococcus neoformans). All of the tested 5-trichloromethyldihydroisoxazoles exhibited antibacterial and antifungal activities at the tested concentrations. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications (R) to view the free supplemental file.