Synthesis of dl-Naproxen via Rearrangement of 2-Haloethyl-2-(6’-methoxy-2’-naphthyl)-4-methyl-1,3-dioxolane

Methoxy 2 propionyl naphthalene was halogenated with cupric halide, then ketalated with 1,2 propanediol, catalytically rearranged by Zn(OAc) 2 or ZnO to give dl naproxen in yield of 85%~90 4% based on 6 methoxy 2 propionyl naphthalene. All reactions were carried out in one pot without additional separation of the intermediates. The route of catalytic rearrangement by using cupric chloride as halogenating agent and zine oxide as catalyst via 2 chloro 2 (6 methoxy 2 naphthyl) 4 methy 1,3 dioxolane appeared more economical due to the cheapness of reagents and simplicity in separation.