Pyridine → 2-[(p-Cyclohexylphenyl)-oxomethyl]-pyridine

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Reaction Steps

10.0 g of chromium trioxide are added in portions at 5° C, whilst stirring and with exclusion of moisture, to a solution of 15.8 ml of pyridine in 200 ml of absolute methylene chloride, behind a protective shield. After the completion of the addition the mixture is stirred for a further 30 minutes at room temperature, 2.8 g of crude 2-[(p-cyclohexylphenyl)-hydroxymethyl]-pyridine, dissolved in 10 ml of methylene chloride, are then added all at once and the mixture is stirred for a further 20 minutes at room temperature. The mixture is decanted off from the brown resin which is formed and is partitioned at 0° C between 50 ml of methylene chloride and 2 lots of 50 ml of saturated sodium bicarbonate solution. The organic phase is washed successively with twice 50 ml of 0.1 N hydrochloric acid and twice 50 ml of water, dried over sodium sulphate and evaporated in vacuo. Chromatography of the evaporation residue on 200 g of silica gel, using chloroform as eluant, and fractional crystallisation from cold ethanol, yields 2-[(p-cyclohexylphenyl)-oxomethyl]-pyridine of the formula ##STR13## of melting point 44°-45° C (boiling point 185°-190°/0.35 mm).

Provenance & Evidence