CMC Catalyzed Multicomponent Mannich Reaction for Synthesis of Lawsone Family Pigments

Naphthoquinones are natural pigments that widely distributed in nature and have important biological activities. Lawsone (2-hydroxy-1,4-naphthoquinone) and its synthetic derivatives, and especially those containing nitrogen, have promising potential for the treatment of different diseases due to their antibacterial, antifungal, antiviral, antitumor and antiparasitic effects [1].

     The Mannich reaction is one of the most widely used three component reactions which utilizes a non-enolizable aldehyde, a primary or secondary amine and an enolizable carbonyl compound resulting -amino carbonyl compounds [2]. In this work, we used carboxymethyl cellulose (CMC) as heterogeneous catalyst for multicomponent mannich reaction. CMC is a cellulose derivative with carboxymethyl groups, it is widely used, and inexpensive, biodegradable.

     Synthesis of 2-hydroxy-1,4- naphtoquinone derivatives were performed by simple reaction between 2-hydroxy-1,4- naphtoquinone, aromatic aldehydes and amines in the presence of CMC. The advantages of this procedure are excellent yields within short times, green catalyst and mild reaction conditions.