3,3′-(Arylmethylene)bis(2-hydroxynaphthalene-1,4-dione) as the Main Product of the Mannich Reaction of 2-Hydroxy-1,4-Naphthoquinone with 4 H -1,2,4-Triazol-4-Amine and Various Aldehydes

Abstract

The Mannich reaction of lawsone with various aldehydes and 4H-1,2,4-triazol-4-amine gave unexpected 3,3′-(arylmethylene)bis(2-hydroxynaphthalene-1,4-dione) derivatives. With 2,4-dihydroxybenzaldehyde under the same conditions, it led to the formation of 3-hydroxy-12-(3-hydroxy-1,4-dioxo-1,4-dihydronaphthalen-2-yl)-6H-benzo[b]xanthene-6,11(12H)-dione instead of various triazolylaminonaphthoquinones.