Veratrole → 4-(3,4-Dimethoxyphenyl)-4-oxobutanoic acid

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Reaction Steps

The naphthalenes of formulas A and B are known to the art. Moreover, they can be prepared by conventional means. For example, 1,2-dimethoxybenzene is treated with succinic anhydride and aluminum chloride in a hydrocarbon solvent to afford 4-(3',4'-dimethoxyphenyl)-4-oxobutanoic acid. This is reduced by treatment with sodium borohydride, hydrogenolyzed by treating with palladium charcoal catalyst and hydrogen to furnish 4-(3',4'-dimethoxyphenyl) butanoic acid. The corresponding acid chloride is prepared such as by teatment with thionyl chloride, and the acid chloride is treated with aluminum chloride to afford 6,7-dimethoxy-1-tetralone. The tetralone is reduced and hydrogenolyzed by the means described above to furnish 6,7-dimethoxytetralin which is dehydrogenated by treating with palladium charcoal catalyst to afford 2,3-dimethoxy naphthalene. By utilizing 1-methyl-3-fluorobenzene in the above process, 6-methyl-8-fluoro-4-tetralone and 6-fluoro-8-methyl-4-tetralone (as intermediates) and 1-methyl-3-fluoro naphthalene and 1-fluoro-3-methyl naphthalene are prepared. The mixture of naphthalenes are separated by conventional means, such as vacuum distillation.

Provenance & Evidence