1,2-Epoxybutane → 3-Phenyl-2(S)-phthalimidopropan-1-al

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Reaction Steps

1 mol of 1,2-butylene oxide and 23.5 g of Pd/C (5% Pd) were added to a solution of 0.5 mol of 3-phenyl-2(S)-phthalimidopropionyl chloride in 1200 ml of toluene. The suspension was hydrogenated at room temperature and atmospheric pressure while stirring vigorously for 17 hours, whereby 11.3 l of hydrogen were taken up. Thereafter, the suspension was filtered over a filter aid and the residue was washed with toluene. The filtrate and washings were combined and treated while stirring with a solution of 0.5 mol of sodium pyrosulphite in 1 l of water. After stirring at room temperature for 4.5 hours the phases were separated. The aqueous phase was washed with 500 ml of toluene. The toluene phases were washed with 350 ml of water. The combined aqueous phases were treated with 1400 ml of toluene and 420 ml of 3N sulphuric acid and stirred at 60° for 6 hours. Thereafter, the phases were separated and the aqueous phase was extracted with 500 ml of toluene. The toluene phases were washed with water, combined, dried over MgSO4 and evaporated. There were obtained 97.8 g (70%) of (S)-α-benzyl-1,3-dioxo-2-isoindolineacetaldehyde as a white solid, melting point 115°-117°, [α]D20 -200° (1% in ethyl acetate).

Provenance & Evidence