A novel route for the synthesis of 2-chloro-3-[trans-4-(4-chlorophenyl) cyclohexyl]-1,4-naphthoquinone and its process development studies

Abstract

Present work reports a novel and commercially viable method for the synthesis of 2-chloro-3-[trans-4-(4-chlorophenyl) cyclohexyl]-1,4-naphthoquinone 1, a renowned intermediate of Atovaquone (an antimalarial drug). Majority of the prior arts disclose the synthesis of this intermediate from the expensive starting material 2-chloro-1,4-naphthoquinone 2, in relatively low yield. In this regard, it was considered worthwhile to synthesize 1 by a novel route using cheaper starting material 2,3-dichloro-1,4-naphtoquinone 5, in high yield and purity. In the present study, emphasis was given for selecting the reagents and solvents, optimizing the reaction conditions, recovery and reuse of solvents and silver salt. This optimized novel process is cost effective and generate less effluents.