Synthesis and Structures of New Enaminones

摘要: Two isomeric enaminones were obtained by reaction of ethyl 2-hydroxy-4-(4-hydroxy-6-methyl2H-pyran-2-on-3-yl)-4-oxo-2-butenoate (1) and amines (aniline, benzylamine, butylamine tyramine) in ethanol. The structures isomers studied 13C 1H NMR spectra, whereas the case 2b, 3a, 4a (Scheme 1), crystal have been determined single X-ray diffractometry. compounds 2b 3a exist solid state as N–C=C–C=O, is N–C=C–C–OH tautomeric form 2, A B, respectively). All three exhibit very short intramolecular hydrogen bonds O–H···O [in range 2.396(3) − 2.448(3) A] N–H···O 2.580(5) 2.679(3) type, that are reinforced delocalization. addition stabilized C–H···O weak bonds. In discrete dimers formed eight-membered ring containing bonds; 4a, infinite chains along [1 0 1] direction formed.