Veratraldehyde → 2-[(3,4-Dimethoxyphenyl)methylidene]-1,3-dithiolane

Beteiligte Stoffe

Reaktionsschritte

A solution of 2-diethoxyphosphoryl-1,3-dithiane (23.4 g) and 3,4-dimethoxybenzaldehyde (16.0 g) in dichloromethane (70 ml) is added to a mixture of dichloromethane (85 ml), a 50% aqueous solution of sodium hydroxide (170 ml) and triethylbenzylammonium chloride (1.4 g). The mixture is stirred for 24 hours at room temperature. The two phases are then separated. The aqueous solution is extracted with dichloromethane (100 ml) and the combined organic solutions are washed with a 10% aqueous solution of ammonium chloride (3×100 ml) and with water (2×100 ml). The dichloromethane is dried over magnesium sulphate and evaporated in vacuo. The residue is purified by column chromatography on silica gel using chloroform as eluant. The product is dried in vacuo to constant weight to yield (1,3-dithiolan-2-ylidene)-(3,4-dimethoxyphenyl)-methane, m.p. 74°-75°.

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