Aza-Michael addition-elimination led synthesis, characterization and X-ray crystallography of novel trifluoromethylated-enaminone derivatives

Enaminones are important synthetic intermediates for the construction of diverse heterocyclic scaffolds owing to their push-pull electronic structures. A series of novel (Z)-1-(3,5-bis(trifluoromethyl)phenyl)-3-(aryl/alkyl)prop-2-en-1-ones (5, 6) and (Z)-3-(aryl/alkylamino)-1-(4-(trifluoromethyl)phenyl)prop-2-en-1-ones (9, 10) were synthesized with (E)-1-(3,5-bis(trifluoromethyl)phenyl)-3-(dimethylamino)prop-2-en-1-one (2) & (E)-3-(dimethylamino)-1-(4-(trifluoromethyl)phenyl) prop-2-en-1-one (8) as starting materials. The structures of the fluorinated enaminones were established with the help of spectral and analytical data. X-ray crystallographic study for a model compound (6a) gave a vivid image showing the existence of the product in Z-form unlike the corresponding intermediate that exists in E-form.