Reaction Condition Dependent Multicomponent Reaction for the Synthesis of Substituted and Fused Naphthoquinone Derivatives

ABSTRACT Herein, we report a reaction condition‐dependent metal‐free one‐pot multicomponent methodology for the efficient synthesis of substituted and fused naphthoquinone derivatives using 2‐hydroxy‐1,4‐naphthoquinone, cinnamaldehyde derivatives, and 2‐amino‐1,4‐naphthoquinone. Refluxing in ethanol with p ‐TSA (10 mol%) afforded substituted naphthoquinone ( 4 ), whereas the reaction in acetic acid under reflux conditions resulted in fused naphthoquinone ( 5 ). All of the synthesized compounds were characterized using spectroscopic techniques such as IR, 1 H NMR, 13 C NMR, and HRMS. This methodology features readily available starting materials, short reaction times, a simple experimental procedure, facile purification, good product yields, and a broad substrate scope.