Synthesis of Spiro 1,3-Oxazines <i>via</i> Three-Component Reaction of Conjugated Imines, Dialkyl Acetylenedicarboxylates and <i>N,N</i>'-Disubstituted Parabanic Acids

A series of structurally diverse spiro 1,3-oxazines were conveniently prepared from three-component reaction conjugated imines, dialkyl acetylenedicarboxylates (DAAD), and N,N'-disubstituted parabanic acids in dry dichloromethane without catalyst. Initially, various imines synthesized aniline derivatives with cinnamaldehyde. Subsequently, DAAD N,N'-substituted led to mixture the corresponding spirocyclic high yields. The obtained diastereoisomers isolated characterized by FT-IR, 1H, 13C NMR spectral data, elemental analyses mass spectrometry.