Solvent and Solubility Effects on Quinone Ratios

Abstract

Monoquinones and diquinones are a biologically and chemically important class of compounds that can be found in numerous natural products such as: thymoquinone, oosporein, coenzyme Q, embelin and the respective dimer, biembelin. These 1, 4-benzoquinone derivatives exhibit prominent pharmacological applications such as antibiotic, anti-tumor, anti-malarial, anti-coagulant, and anti-convulsant activity. Though quinones can be prepared by a variety of processes, they are most commonly synthesized through the treatment of hydroquinone dimethyl ethers with ceric ammonium nitrate (CAN). However, this can lead to an unpredictable mixture of monoquinone and diquinone as the products. This project has investigated the effect of solvent and substrate water solubility on monoquinone / diquinone product ratios with the aim of being able to consistently and predictably favor one (monoquinone or diquinone) over the other.