Phthalimide → 2-[5-(1,2-Dithiolan-3-yl)pentyl]isoindole-1,3-dione

Participants

Reaction Steps

3.25 ml of dimethyl azodicarboxylate were added dropwise to a solution of 5.77 g of triphenylphosphine in 20 ml of tetrahydrofuran, whilst ice-cooling, and then the mixture was stirred at room temperature for 30 minutes. 3.24 g of phthalimide were then added to the reaction mixture, after which a mixture of 20 mmol of 5-(1,2-dithiolan-3-yl)pentanol (prepared as described in Preparation 1) in 30 ml of toluene and 10 ml of tetrahydrofuran was added dropwise, and the mixture was stirred at room temperature for one hour. The reaction mixture was allowed to stand overnight at room temperature, after which 1.57 g of triphenylphosphine and 0.89 ml of dimethyl azodicarboxylate were added. The resulting mixture was stirred at room temperature for 7 hours and 30 minutes. 0.88 g of phthalimide, 1.57 g of triphenylphosphine and 0.89 ml of dimethyl azodicarboxylate were then added to the reaction mixture. The reaction mixture was allowed to stand at room temperature for 4 days. At the end of this time, the solvent was removed from the reaction mixture by distillation under reduced pressure, and the residue was subjected to silica gel column chromatography, using 1:6 and 1:4 by volume mixtures of ethyl acetate and hexane as eluent. The solvent was removed from the eluate by distillation under reduced pressure, and 30 ml of toluene were added to the residue. 1 ml of the resulting mixture was weighed, and the solvent was removed from it by distillation under reduced pressure, to give 165 mg of the title compound as an orange oil having an Rf value of 0.35 (silica gel thin layer chromatography; using a 1:4 by volume mixture of ethyl acetate and hexane as the developing solvent).

Provenance & Evidence