Oxidative Dehydroxycyclization of Catechols with o-Mercaptoanilines to Access 1-Hydroxyphenothiazines
Hanyu Zhou1, Xuchen Shang1, Wenhao Li1
1Green Catalysis Center, College of Chemistry, Zhengzhou University, Zhengzhou, Henan 450001, P. R. China.
Abstract:
The protocol of aerobic oxidative dehydroxycyclization installed in the synthesis of rarely studied 1-hydroxyphenothiazines from catechols and o-mercaptoanilines is presented. Utilizing a natural renewable low-toxicity gallic acid as an organocatalyst, this established transformation proceeded smoothly in an aqueous ethanol solution under mild conditions with good functional group compatibility and up to a 94% isolated yield. This protocol is also characterized by its operational simple workup involving only recrystallization, revealing its sustainability and synthetic practicability.
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