Synthesis of benzofused-P-indolequinones from 1,4-naphthoquinone and selective N-debenzylation by Dess-Martin periodinane
p-Indolequinones are important heterocycles since they display interesting bioactivities such as anticancer activities as well as the ability to trigger drug release in drug targeting research. Additionally, they are also useful in precursors for the synthesis of bioactive compounds. Over decades, many methodologies have been investigated for the synthesis of p-indolequinones. Among those, cyclization of quinones plays an important role in convenient synthesis of these compounds. However, the great majority of these methods only describe quinones as electrophiles in cyclization. In our research, we found an intramolecular nucleophilic attack of quinone to an in-situ generated carbonyl group and developed a new methodology for benzofused p-indolequinones synthesis in one-pot. Moreover, a selective debenzylation of tertiary amines using a non-metal reagent was also explored. Metal complexes have been dominantly used for N-dealkylation of amines. However, they resulted in low selectivity of debenzylation over dealkylation as well as the process of disposing heavy metals. Non-metal reagents, on the other hand, are efficient in debenzylating mostly secondary amines. For the first time, the attack of tertiary amine to Dess-Martin periodinane was discovered in our work and was developed as a selective method to deprotect benzyl group of tertiary amines. ^
Luu, Quang Huynh, "Synthesis of benzofused-P-indolequinones from 1,4-naphthoquinone and selective N-debenzylation by Dess-Martin periodinane" (2015). ETD Collection for University of Texas, El Paso. AAI10000814.