Phenanthrenequinone

Preparation

Phenanthrenequinone is obtained by the oxidation of the hydrocarbon phenanthrene C14H10. Upon reduction with sulphur dioxide, it yields phenanthrenehydroquinone which absorbs oxygen from the air forming a black quinhydrone. Upon further oxidation the phenanthrenequinone is again formed. 9,10-Phenanthrenequinone is prepared by oxidation of phenanthrene with dihydroxy phenylselenonium benzenesulfonate in boiling dioxane-water. 9-methoxyphenanthrene is obtained when the reaction is carried out in methanol. https://www.tandfonline.com/doi/abs/10.1080/00397919708004809

Reactions

9,10-Phenanthrenequinone (PQ) reacts with ketones under FeCl3 catalysis to furnish a variety of structurally diverse furan annulated products. While the reaction of PQ with acetone and cyclopentanone furnishes furan annulated ketals, its reaction with ethyl alkyl ketones provides 3-furaldehyde annulated products. In contrast to the reaction of PQ with cyclopentanone, its reaction with cyclohexanone furnishes a tetrahydrobenzofuran annulated secondary alcohol. The reactions of PQ with cycloheptanone and cyclooctanone take a different course to provide 7,8-dihydro-6H-cyclohepta[b]furan and 6,7,8,9-tetrahydrocycloocta[b]furan annulated products, respectively. Mechanistically, the above reactions go through aldol condensation, dehydration and cyclization to form furan-phenanthrene annulated products where in each step FeCl3 catalysis is involved. https://pubs.rsc.org/en/content/articlelanding/2012/ra/c2ra20499a

Synthesis Reference(s)

The Journal of Organic Chemistry, 52, p. 3472, 1987 DOI: 10.1021/jo00391a065

Safety Profile

Poison by acute intraperitoneal route. Questionable carcinogen with experimental tumorigenic data by skin contact. Mutation data reported. When heated to decomposition it emits acrid smoke and irritating fumes.

Purification Methods

Crystallise the quinone from dioxane or 95% EtOH and dry it under vacuum. [Beilstein 7 IV 2565.]

General Description

Phenanthrenequinone, also known as 9,10-Phenanthraquinone, is a quinone derivative of phenanthrene formed through the oxidation of phenanthrene or its hydroxylated derivatives. It serves as a key intermediate in organic synthesis and biomimetic reactions, such as those involving flavin-mediated oxygen transfer, where it can be produced from the oxidation of 9-hydroxyphenanthrene derivatives. Its structure and reactivity make it relevant in studies of electroluminescent materials and enzymatic-like oxidation processes.