Synthesis of p-Nitroenamines

Abstract

Primary and secondary acyclic β-nitroenamines were prepared and their structures were elucidated. N, N'-Bis(1-methyl-2-nitrovinyl) polymethyIenediamines [7]were obtained by the reaction of 3-nitro-2, 4-pentanedione. [2]with polymethylenediamines (n=2, 3, 4 and 6). Products [7](n =2) and [7](n =3) were allowed to react with transition metal( II ) acetate to give the corresponding metal(II) complexes C [8] (n =2) Cu, [8](n =2) Ni, [8](n =2) Co and [8] (n =3) Cu in good yield. The reaction of [2] with ammonia or primary amines in the presence of titanium (IV) chloride afforded the corresponding 4-(monosubstituted amino)-3-nitro3-penten-2-one [6] in 37-69.5% yield (substituent R: H, Me, PhCH2 and Ph). Nitroacetone C 33 reacted similarly to give the corresponding 2-(substituted amino)-1-nitropropene C [4]in 51.5 -91% yield. Based on the spectral data, [7] and 4 were concluded to be present entirely in the chelated structure of nitroenamine form NH ON and [6] were in the chelated structure of s3-aminoenone form NH…O=C.