Critical Assessment of Sustainable Synthetic Methodologies for the Construction of Oxazole and Benzoxazole Derivatives

ABSTRACT

Oxazole and benzoxazole motifs are privileged heterocyclic frameworks with broad relevance in pharmaceuticals due to their exceptional biological activity. In response to increasing demands for sustainable chemical protocols, significant strides have been taken toward the development of greener strategies for their construction. This review critically examines existing green protocols for oxazole‐based compound synthesis, with an emphasis on non‐conventional techniques and recyclable catalytic systems. Microwave and ultrasound‐assisted approaches are demonstrated as technologies that enhance reaction efficiency, reduce energy input, and facilitate transformations under milder conditions. Meanwhile, the role of ionic liquids is evaluated in terms of their multifunctionality as solvents and catalysts. Advances in nanoparticle catalysis are discussed for their high activity, ease of recovery, and reuse. In this review, we comparatively analyze each methodology through a green chemistry lens, while also providing a structured framework for selecting sustainable strategies. Furthermore, we have also identified emerging opportunities for the future development of environmentally benign oxazole synthesis.