| 摘要 |
<p>PURPOSE:To obtain the subject substances useful as an intermediate for amino acid esters, intermediate for peptide synthesis and raw material for aspartame which is a dipeptide sweetener, by reacting an N-protected aspartic acid with phosgene in an inert organic solvent in the presence of a metal (hydr)oxide. CONSTITUTION:The objective anhydride can be produced by reacting an N- protected aspartic acid (e.g., N-benzyloxycarbonyl-L-aspartic acid) with phosgene in the presence of oxides, hydroxides or salts of various metals (e.g., Li, Na, K, Mg, Ca, Fe, Cu, Zn, Sn or Al) in an inert organic solvent (e.g., ethyl ether or THF) preferably at 10-60 deg.C. The amount of said metal compound is preferably 0.001-5mol% based on the N-protected aspartic acid.</p> |
