Abstract
The preparation and purification of acetylcoronene, coronaldehyde, and methylcoronene has been reinvestigated. The oxidation of these compounds, under a variety of conditions, has been attempted; the expected oxidation of acetylcoronene and coronaldehyde to coronene-carboxylic acid has not been observed. The preparation of diethyl coronylidenemalonate and cyanocoronene is reported; the latter, on hydrolysis, gives coronenecarboxylic acid. The nitration of the monosubstituted coronene derivatives has been attempted. Under mild nitration conditions in no experiment was one nitro group introduced, in three cases - from acetylcoronene, methylcoronene, and diethyl coronylidenemalonate - were two nitro groups introduced. The low solubility of these compounds in appropriate solvents did not allow proton magnetic resonance studies to be carried out. Under strong nitration conditions acetylcoronene, cyanocoronene, coronaldehyde, and coronenecarboxylic acid gave pentanitroderivatives; the attempted interconversions of these products are reported. Their relationship with the known compound, hexanitrocoronene, has been investigated. Formylation of methylcoronene and dimethylcoronene, to give methylcoronaldehyde and dimethylcoronaldehyde respectively, was carried out by treatment with n-butyl dichloromethyl ether, in the presence of titanium tetrachloride; the aldehydes, on reduction with hydrazine hydrate (100%) and potassium hydroxide in trigol, gave dimethylcoronene and trimethylcoronene, respectively. Methylcorononitrile has been prepared from methylcoronaldehyde. The base-catalysed interaction between diethyl malonate and methylcoronaldehyde, and between diethyl maIonate and difmethylcoranaldehyde gave the appropriate condensates. All of the products resulting from the formylation processes appear to be mixtures.