Quinone Formation via Ceric Ammonium Nitrate Oxidations of 2-Alkyl-1,4-dialkoxybenzenes

Abstract

Quinones are cyclohexadiendiones that have a variety of uses ranging from medical applications to synthetic building blocks. Medicinal applications stem from the potent biological activity (e.g. antitumor and antibiotic) these compounds and some derivatives possess. The most common preparation method to access these compounds is oxidative demethylation of hydroquinone dimethyl ethers typically using ceric ammonium nitrate (CAN). Oxidation using CAN can yield a product mixture of the (mono)quinone and the symmetric dimeric quinone. Previous work in our group has resulted in the development of several protocols for altering the monoquinone to diquinone ratio by altering reaction conditions (e.g. substrate concentration, mode of addition, etc.). The current focus further explores manipulation of this ratio and reaction efficacy through substrate solubility and cerium coordination. We will discuss how ether linkages of various hydrophobicities and coordination modes change product outcome and if altering a single ether linkage or both linkages affect the product ratio.