Fluorobenzene → 2-(4-Fluorobenzoyl)-naphthalene-3-carboxylic acid

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Reaction Steps

45.0 g (227 mmols) of 2,3-naphthalenedicarboxylic anhydride are suspended in 200 ml (2.1 mols) of fluorobenzene, and in the course of 5 minutes, with vigorous stirring, 75.5 g (565 mmols) of powdered aluminium chloride are added (exothermic reaction up to about 32° C.). The dark-red suspension is refluxed and stirred for 6 hours, and the solution is then allowed to cool to room temperature; it is subsequently poured onto about 500 g of ice, and is stirred until completion of hydrolysis. Excess fluorobenzene is evaporated off, and the product obtained is suspended in water. The suspension is filtered off, the filtrate is afterwards washed and the product is dried. There are obtained 76 g of crude 2-(4-fluorobenzoyl)-naphthalene-3-carboxylic acid. The crude product is stirred up with 2 liters of 10% sodium carbonate solution; the resulting solution is then acidified with hydrochloric acid, and the white precipitate is filtered off and dried. The yield is 54.2 g (81% of theory) of 2-(4-fluorobenzoyl)-naphthalene-3-carboxylic acid. MS: (M+ =294; M+ --COOH=249, M+ --COO=250, M+ --C6H4F=199); IR spectrum (KBr): OH about 3300 cm-1 ; C=O double bands 1695/1705 cm-1.

Provenance & Evidence