2-[4-(3'-Oxocyclohexyl)phenyl]propionic acid (4.0 g; 16.2 mmoles) is
dissolved in 1 N sodium hydroxide (55 ml) and treated with hydroxylamine
hydrochloride (2.22 g; 32 mmoles) during 24 h at room temperature. The
gummy precipitate formed on acidification is converted to the sodium salt in
aqueous solution which is then evaporated to dryness. The residue is
dissolved in methanol or ethanol to remove an insoluble. After evaporating off
the alcool, the sodium salt is again dissolved in water and converted to the
acid which is crystallized from water-methanol (1:1), to give 3.0 g (yield
70%) of 2-[4-(3'-hydroxyimino-cyclohexyl)phenyl]propionic acid, melting point 178°C.
