4-Methylmorpholine → N-t-butoxycarbonyl-L-methionyl-L-aspartyl-D-alanine amide

Participants

Reaction Steps

14.5 Parts of N-methylmorpholine is added to a stirred solution of 14.33 parts of L-aspartyl-D-alanine amide monohydrate in 189 parts of dimethylformamide and 12.6 parts by volume of a 5.60 N HCl/dioxane solution. Then, 33.2 parts of N-t-butoxycarbonyl-L-methionine 2,4,5-trichlorophenyl ester is added and the resulting mixture stirred for about 18 hours at room temperature. The solvent is removed in vacuo and the resultant syrupy oil dissolved in ethyl acetate. To this solution is added 0.82 parts of N,N-diethylaminoethylamine and the resulting mixture is stirred for about 35 minutes. The mixture is then washed twice with 5% potassium hydrogen sulfate solution, dried over anhydrous sodium sulfate, and stripped under reduced pressure to a gummy residue. The gum is triturated with ethyl ether, to yield crystals which are filtered and dried to afford N-t-butoxycarbonyl-L-methionyl-L-aspartyl-D-alanine amide. This product melts at about 107-110° C., and is represented by the following formula.

Provenance & Evidence