Masato Takagi

Reaction of 9-α-chloronaphthylmethylanthracene and its homologues with nucleophiles under solvolytic conditions. Effect of the increase of bulk at C-α on the reaction site

The reaction of 9-α-chloronaphthylmethylanthracene and its homologues with (a) sodium ethoxide in ethanol, (b) ethanol in the presence of triethylamine, (c) sodium borohydride in aqueous diglyme, and (d) sodium azide in aqueous NN-dimethylformamide has given a mixture of substituted anthracenes and 9,10-dihydroanthracenes. The yield of the latter increases as the aryl group at C-α becomes larger. The phenyl ring of a chloride at C-10 causes the reaction at this position to be retarded. The relative thermodynamic stabilities between the anthracenes and the 9,10-dihydroanthracenes have been investigated.

Synthesis of 9-methylene-9,10-dihydroanthracene by lithium aluminium hydride reduction of (9-anthrylmethyl)trimethylammonium chloride

Treatment of (9-anthrylmethyl) trimethylammonium chloride (2a) with 1 mol equiv. of lithium aluminium hydride (LAH) in refluxing tetrahydrofuran gave predominantly 9-methylene-9,10-dihydroanthracene (3a). However, reaction with 3 mol equiv. of LAH gave a mixture of 9-methyl-9,10-dihydroanthracene (5a) and 9-(9-anthrylmethyl)-9-methyl-9, 10-dihydroanthracene (6a), these products being formed by processes involving nucleophilic attack of excess of LAH on compound (3a).