Trityl chloride → Methyl trityl-L-threoninate

Participants

Reaction Conditions

Reaction Steps

Methyl L-threoninate hydrochloride (16.9 g, 100 mmol), prepared by the method of Lall, J. Org. Chem., 67, pp. 1536-1547, was dissolved in 200 mL of anhydrous CH2Cl2 and the solution was cooled to 0° C. under N2. Triethylamine (27.8 mL, 200 mmol) was then added followed by triphenylmethylchloride (27.9 g, 100 mmol) and the reaction was stirred and allowed to warm to ambient temperature overnight. The reaction mixture was then filtered and the resulting solid was rinsed with several portions of CH2Cl2. The combined filtrates were concentrated under reduced pressure and the resulting syrup was dissolved in 150 mL of ethyl acetate and then washed successively with 100 mL of saturated aqueous NaHCO3 solution, 100 mL of 10% aqueous citric acid solution, 50 mL of H2O and 50 mL of brine. The organic portion was then dried over Na2SO4, filtered and concentrated under reduced pressure to give a syrup. The syrup was treated with 200 mL of hexanes and the mixture was stirred rapidly overnight to give a white solid. The solvent was decanted and the solid was washed with an additional portion of hexanes. The mixture was filtered and the isolated white solid was dried under vacuum for several days to give methyl N-trityl-L-threoninate (32.4 g) as a sticky, white powder.

Provenance & Evidence