Sodium Hydroxide → 4-[2-Benzoyl-5-(pyridin-3-ylmethoxy)phenoxy]-4-(2-methylphenyl)butanoic acid

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A solution of tert-butyl 4-[2-benzoyl-5-(pyridin-3-ylmethoxy)phenoxy]-4-(2-methylphenyl)butanoate, thought to be the (R)-enantiomer, (1 g) in a mixture of methanol (10 mL) and tetrahydrofuran (10 mL) is treated with 5 M aqueous sodium hydroxide solution (7.5 mL) and the reaction stirred at ambient temperature for 24 hours. The reaction is concentrated to low volume, acidified to pH 5 with dilute hydrochloric acid, and extracted into dichloromethane (2×30 mL). The combined organic layers are washed with brine, dried over magnesium sulphate, filtered and concentrated under reduced pressure to leave a yellow gum. Trituration with diethyl ether and recrystallization of the resultant solid from acetonitrile containing a little decolourizing charcoal gives 4-[2-benzoyl-5-(pyridin-3-ylmethoxy)phenoxy]-4-(2-methylphenyl)butanoic acid, thought to be the (R)-enantiomer, (0.2 g) as a pale yellow solid, m.p. 185-186° C. [Elemental analysis:- C, 74.83; H, 5.65; N, 2.91%; Calculated:- C, 75.01; H, 5.72; N,2.87%].

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