3-[(3,6-dihydro-4-phenyl-1(2H)-pyridinyl)methyl]cyclohexanone → 1-[(3-Phenyl-3-cyclohexenyl)methyl]-4-phenyl-1,2,3,6-tetrahydropyridine

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Reaction Steps

To a solution of 3-[(3,6-dihydro-4-phenyl-1(2H)-pyridinyl)methyl]cyclohexanone (Example A) (5.9 g) in 400 mL of tetrahydrofuran is added a solution of phenylmagnesium bromide (9.13 mL, 3.0M in diethyl ether), dropwise under nitrogen, at 0° C. The mixture is stirred at room temperature for 1 hour, then cooled in an ice bath and quenched with 250 mL of 10% aqueous hydrochloric acid solution. The solvent is evaporated in vacuo and the residue partitioned into chloroform/5% aqueous ammonium hydroxide solution. The organic extract is dried over magnesium sulfate and filtered. The filtrate is treated with trifluoroacetic acid (4.2 mL) and stirred overnight at room temperature. The solvent is evaporated in vacuo, and the residue is partitioned into ethyl acetate/5% aqueous ammonium hydroxide solution. The organic extract is dried over magnesium sulfate, filtered, and concentrated. The crude product is purified by medium pressure chromatography to give 3.9 g of (±) -1,2,3,6-tetrahydro-4-phenyl-1-[(3-phenyl-3-cyclohexen-1-yl)methyl]pyridine; mp 90°-95° C. as an off-white solid (Example 1) and 2.7 g of (±)-1,2,3,6-tetrahydro-4-phenyl-1-[(3-phenyl-2-cyclohexen-1-yl)methyl]pyridine; mp 124°-126° C. as a tan solid (Example 1a).

Provenance & Evidence