Iminophosphoranes in Heterocyclic Synthesis: A Facile Synthesis of Pyrido[4,3‐D]Pyrimidine and Pyrido[4,3‐D][1,3]Oxazine Derivatives via Intermolecular aza‐Wittig Reactions

Abstract

A novel series of pyrido[4,3‐d]pyrimidine and pyrido[4,3‐d][1,3]oxazine derivatives were synthesized via tandem aza‐Wittig and annulation reactions with the corresponding iminophosphoranes, aromatic isocyanate, and amines. All newly synthesized compounds were elucidated by considering the data of both elemental and spectral analysis.