Síntese de 1,1,1-trifluoro-4-metoxi-3-alquen-2-onas funcionalizadas e 1,2-azóis derivados

Abstract

This work describes the application of the method of trifluoroacetic anhydride acetal acylation to four new functionalized ketones: 6-methyl-5-hepten-2-one, 4-phenyl-4- oxobutanoic acid (3-benzoylpropionic acid), 5-bromo-2-acetylthiophene and 2- propionylthiophene. The acylated products were obtained as β-trifluoromethyl ketones alkoxyvinyl and β-diketones. The product derived from 2-propionylthiophene was obtained as dihydrate, 3,3-dihydroxy-4,4,4-trifluoro-1-(2-thienyl)-2-butanone, its structure was confirmed by X-ray diffraction crystallography. The acylated dielectrophilic precursors were cyclized with dinucleophiles hydroxylamine, hydrazine, semicarbazide and thiosemicarbazide to form the corresponding 5-trifluoromethyl-4,5-dihydroisoxazoles, 5-trifluoromethyl-4,5-dihydro-1H-pyrazoles and trifluoromethyl-1H-pyrazole in good yields (>80%). The molecular structure of the synthesized products were assigned based on the data of 1H NMR, 13C and X-ray diffraction.