Dimethyl Sulfoxide → N-tosylsarcosyl-L-prolinal

Participants

Reaction Steps

In the next step, a solution of dimethyl sulfoxide (DMSO) (35.3 ml, 0.491 mol) in methylene chloride (970 ml) is added dropwise, over a period of 2.5 hours at -60° C. under an atmosphere of nitrogen, to a solution of oxalyl chloride (44.7 ml, 0.491 mol) in methylene chloride (970 ml), and the mixture is stirred for a further five minutes. A solution of N-tosylsarcosyl-L-prolinol (80 g, 0.245 mol) in methylene chloride (950 ml) is then added dropwise to the mixture over a period of 75 minutes, and the mixture is stirred for a further thirty minutes. Triethylamine (348 ml, 2.45 mol) is then added dropwise thereto over a period of ten minutes, and the mixture is stirred for a further ten minutes. After brought back to room temperature, the mixture is washed with water (2 l×2) and the organic layer is concentrated to dryness under reduced pressure. The residue is dissolved in ethanol (320 ml), and the solution is vigorously stirred for 15 minutes after addition of a saturated aqueous solution of sodium hydrogen carbonate (250 ml) and water (438 ml). The ethanol is then distilled off under reduced pressure, and water (600 ml) is added to the residue. The mixture is extracted with chloroform (300 ml) and ether (500 ml×2) and the organic layers are discarded. The aqueous layers are adjusted with potassium carbonate to a pH higher than 10 and extracted with chloroform. The organic layer is separated, washed successively with water (500 ml×2), 1N hydrochloric acid (500 ml) and water (500 ml), dried over anhydrous magnesium sulfate and concentrated to dryness under reduced pressure to give N-tosylsarcosyl-L-prolinal (49.5 g, 62.3%).

Provenance & Evidence