Sodium Hydroxide → 5-Methyl-3-(trifluoromethyl)-1,2-oxazole-4-carboxylic acid

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Reaction Steps

A solution of 5-methyl-3-trifluoromethylisoxazole-4-carboxylic acid ethyl ester (2.0 g) and sodium hydroxide (1.1 g) in tetrahydrofuran/water (20 ml/20 ml) was heated at reflux for 18 hours. The tetrahydrofuran was removed in vacuo and the aqueous residue washed with ethyl acetate (50 ml), acidified to pH2 with conc. hydrochloric acid and extracted with ethyl acetate (100 ml). The organic layer was washed with brine (50 ml), separated, dried over magnesium sulphate, filtered and concentrated in vacuo to afford the title compound as a peach-coloured solid (1.4 g).

Provenance & Evidence