Benzaldehyde → 4-(2-Phenylvinyl)pyridine, trans-

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Reaction Steps

A solution of 4-picoline (18.6 g, 0.2 mol) and benzaldehyde (21.2 g, 0.2mol) in acetic anhydride (125 ml) was stirred under reflux for 24 h. The resulting black solution was evaporated, the residue partitioned between ethyl acetate (100 ml) and aqueous sodium carbonate (100 ml) and the liquid phases decanted from the solid residue. The organic layer was washed with sodium carbonate (100 ml), dried (MgSO4), and evaporated to leave a black solid. The solid remaining from the earlier extraction was dissolved in dichloromethane (100 ml), the solution washed with sodium carbonate (75 ml), dried (MgSO4) and evaporated. The combined solid residues were dissolved in methanol (200ml), treated with charcoal, filtered and the filtrate evaporated to leave a brown solid which was triturated with cyclohexane, the suspension filtered and the solid recrystallised from cyclohexane to leave the product as a brown crystalline powder (11.94 g). The combined organic supernatants were chromatographed on silica gel eluting with ethyl acetate/hexanes (7:3) to give a further crop as a yellow solid (6.2 g).

Provenance & Evidence