Synthesis of 3-phenyl-5-(trifluoromethyl)isoxazole and 5-phenyl-3-(trifluoromethyl)isoxazole

✍ Scribed by James W. Pavlik; Jennifer A. Lowell; Vuthichai Ervithayasuporn

• Publisher: Journal of Heterocyclic Chemistry
• Year: 2005
• Tongue: English
• Weight: 65 KB
• Volume: 42
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570420702

✦ Synopsis

Reaction of 4,4,4-trifluoro-1-phenyl-1,3-butanedione with hydroxylamine led to the formation of 5hydroxy-3-phenyl-5-(trifluoromethyl)-4,5-dihydroisoxazole which was dehydrated to 3-phenyl-5-(trifluoromethyl)isoxazole. This isomer can also be synthesized by reaction of 4-chloro-4-phenyl-1,1,1-trifluoro-3buten-2-one with sodium azide. The regioisomer, 5-phenyl-3-(trifluoromethyl)isoxazole was synthesized by reaction of 1,1,1-trifluoro-4-phenylbut-3-yn-2-one with hydroxylamine and by the reaction of 3-chloro-1phenyl-4,4,4-trifluorobut-2-en-1-one with sodium azide. Both isomers were characterized by mass and NMR spectroscopy.