β-ANTHRONYL-β-PHENYL-PROPIONIC ACID AND ITS DERIVATIVES SYNTHESIS OF THE γ-ANTHRONYL-α-HYDRINDONE

Abstract

Benzaldehyde and o-chlorbenzaldehyde were readily condensed with ethyl and methyl malonate, giving rise to unsaturated esters. The esters were condensed with anthrone in alcoholic solution in the presence of piperidine. Hydrolysis of the product with sulphuric acid yielded β-anthronyl-β-phenyl-propionic acid. The chloride of this acid was formed by the action of phosphorus pentachloride. Two tautomeric derivatives of γ-anthronyl-α-hydrindone result from the action of aluminium chloride on β-anthronyl-β-phenyl-propionyl chloride. No benzanthrone derivatives were formed.The action of bromine on the two tautomeric forms of γ-anthronyl-α-hydrindone gave rise to one monobromide only, and oxidation of the two tautomers yielded only anthraquinone and phthalic acid.The method of preparation of β-anthronyl-β-phenylpropionic acid has been improved and the following compounds have been described, as far as the authors are aware, for the first time: the dimethyl and diethyl esters of o-chlor-benzylidene - malonic acid and anthrone - o - chlorbenzylidene - malonic acid; anthrone - benzylidene - diethyl - malonate; β-anthronyl - β- (o - chlorphenyl) - propionic acid; the silver salt, chloride, amide, anilide, methyl and ethyl esters of β-anthronyl-β-phenyl-propionic acid; γ-anthronyl-α-hydrindone (enolic and ketonic forms); γ-anthronyl-β-brom-α-hydrindone; and the hydrazone hydrate, phenylhydrazone, oxime and semicarbazone of γ-anthronyl-α-hydrindone.