“…Asghari and co-workers 68 synthesized spiro 1,3-oxazines 110 via the reaction among N , N ′-disubstituted parabanic acid derivatives 109, imine derivatives 107, and dialkyl acetylenedicarboxylate derivatives (DAAD) 108 in dry dichloromethane without catalyst at room temperature for 1–6 h ( Scheme 49 ).…”