One Stone, Three Birds: One-Pot Synthesis of Pyrido[3,2-a]phenoxazin-5-one Derivatives from o-Aminophenols with Triple Roles, Paraformaldehyde, and Enaminones via the Povarov Reaction

A novel multicomponent cascade cyclization reaction inone potfor the preparation of pyrido[3,2-a]phenoxazin-5-onesfrom simple o-aminophenols, paraformaldehyde, andenaminones has been established. It is noteworthy that o-aminophenol plays multiple roles serving as both a bis-nucleophileand an iminoquinone precursor, which can in situ generate aminophenoxazinonesto undergo the Povarov reaction for the first time to yield pyrido[3,2-a]phenoxazin-5-ones with a high efficiency. Moreover, thephotoluminescence of pyrido[3,2-a]phenoxazin-5-oneshas polarity sensitivity and features aggregation-induced emission(AIE) characteristics, which is promising for bioimaging and theranosticapplications.

Automated summary

A novel multicomponent cascade cyclization reaction has been developed for the synthesis of pyrido[3,2-a]phenoxazin-5-ones using simple o-aminophenols, paraformaldehyde, and enaminones. The o-aminophenol serves as a bis-nucleophile and an iminoquinone precursor, facilitating the formation of aminophenoxazinones for the first time through the Povarov reaction, resulting in high-efficiency synthesis of pyrido[3,2-a]phenoxazin-5-ones. These compounds exhibit polarity sensitivity and aggregation-induced emission (AIE) characteristics, making them promising for bioimaging and theranostic applications.