1,3-Propanedithiol → N,N'-Dicyclohexylurea

Participants

Reaction Conditions

Reaction Steps

As shown in Reaction 1, 2-(thiophene-3-yl)acetic acid) (1 g, 7.03 mmol), propane-1,3-dithiol (0.753 g, 7.03 mmol), and 4-dimethylaminopyridine (4-DMAP) (2.014 g, 1.75 mol) were dissolved in 80 ml of methylene chloride in a three-neck round bottom flask, after which stirring was performed at 60° C. in a nitrogen atmosphere. The stirred mixture solution was slowly added with N,N′-dicyclohexylcarbodiimide (DCC) (2.89 g, 14.06 mol) dissolved in 20 ml of methylene chloride, and was then allowed to react for 9 hours. The reaction solution was washed using saturated aqueous Na2CO3, dried over MgSO4, and filtered. The remaining solvent was removed by rotary evaporation to obtain a yellowish solution. This solution was diluted with acetone, and cooled to 0° C., to obtain residual 1,3-dicyclohexylurea (“DCU”) as a precipitate. This precipitate was removed by filtration through a paper filter, and addition of acetone and removal of the DCU precipitate were repeated until DCU precipitate was no longer evident in the solution. Finally, the remaining solvent was removed by rotary evaporation, and the crude purified using a silica column eluted with a solution of methylene chloride and methanol (60:1 v/v), thereby producing after collection of the fractions and removal of the solvent, S-3-mercaptopropyl-2-(thiophene-3-yl)ethanethioate (“MTE”) (the monomer) as a pure yellow compound. The characteristic H1-NMR spectrum (in acetone-d6) of the product is shown in FIG. 1.

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