烯氨酮晶体结构研究

Study of Crystal Structures of Some Enaminones

研究了氨基分别为1′-四氢吡咯,1′-六氢吡啶和4′-吗啉的1-苯基-3-氨基-2-丁烯-1-酮的晶体结构.它们的构型、构象均为trans,S-cis.由于共轭体系的扩展,这些烯氨酮的氮原子都比相应的烯胺有程度更大的电子离域,其中又以扭式构象的四氢吡咯基的离域程度最高.四氢吡咯形成N-不饱和化合物的特殊活性与此有关.

X-ray crystal strnctures of 1-phenyl-3-disubstituted amino-2-buten-1-ones(disubstituted amino=1’-pyrrolidino,1’-piperidino and 4’-morpholino’)are studied.Their configuration and conformation are all trans,S-cis.Due to the expansion of conjugation system in these molecules,a more important electron delocalization of nitrogen atom in tho enaminone than that in the relative enamine is observed.Favored by the twist conformation of five-membered ring,the electron delocalization is the most pronounced in enamine and enaminone derived from pyrrolidine.This explains the unusual reactivity of pyrrolidine in formingα-disubstituted amino unsaturated compounds.