Hydrochloric Acid → 1,7-Diphenylheptane-3,5-dione

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Reaction Steps

To a suspension of sodium hydride (60% in oil, 17 g) in dry cyclohexane (200 ml), a solution of 2,4-pentanedione (37 g, 0.37 mole) in dry cyclohexane was added dropwise at room temperature with stirring under nitrogen, and the resultant mixture was stirred for 40 min. at the same temperature. To this suspension, N,N,N',N'-tetramethylethylenediamine (91.8 g) was added dropwise, followed by the dropwise addition of n-butyllithium (1.6M in n-hexane solution, 337 g) at 0° C. or lower and the resultant mixture was stirred for 24 hours at room temperature. Then to this suspension, benzyl chloride (93.7 g) was added dropwise at 0°-5° C., stirring was continued for 2 hours at room temperature and allowed to stand overnight. The reaction mixture was poured into dilute hydrochloric acid. The organic layer was separated, washed thrice with H2O, dried over anhydrous MgSO4 and evaporated. The residue (79 g) was distilled under reduced pressure to give 23.5 g of the desired product as a pale yellow oil having a boiling point of 185°-190° C./0.4 mmHg.

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