Synthesis of ubiquinone and menaquinone analogues by oxidative demethylation of alkenylhydroquinone ethers with argentic oxide or ceric ammonium nitrat

It was found that alkenylhydroquinone ethers demethylated with argentic oxide or ceric ammonium nitrate in the presence of 2,4,6-pyridinetricarboxylic acid as a catalyst and afforded ubiquinone-2, menaquinone-2 and their analogs in yields of 53 to 89%. The new approach to the synthesis of starting alkenylhydroquinone ethers as well as 2,4,6-pyridinetricarboxylic acid and its derivatives has been reported.