DL-alanine → 2-PropionaMidopropanoic acid

Participants

Reaction Steps

Trimethylsilyl chloride (52.4 mL, 0.41 mol) was added dropwise to an ice-cooled solution of D,L-alanine (16.71 g, 0.188 mol) and triethylamine (57.5 mL, 0.41 mol) in dichloromethane (190 mL). Once addition was complete, the solution was stirred at room temperature for 1 hour, followed by 1 hour at 40° C. The solution was then cooled to −10° C., propionyl chloride (16.29 mL, 0.188 mol) added dropwise over 15 minutes and, once addition was complete, the reaction was stirred at −10° C. for 2 hours, then 16 hours at room temperature, before cooling in an ice-bath. Water (100 mL) was added, the mixture was stirred for 15 minutes, then the phases separated. The aqueous layer was evaporated under reduced pressure and the residue triturated with acetone. The resulting solid was filtered off, and the filtrate concentrated under reduced pressure, to give an oil. This oil was purified by column chromatography on silica gel using dichloromethane:methanol:0.88 ammonia (89:10:1) as eluant, to give the title compound (20 g; containing 33% triethylamine).

Provenance & Evidence