A new route to L-isoglutamine and a simplified route leading to 1-isoasparagine are described. Carbobenzoxy-L-glutamic acid was converted through preferential activation of its a-carboxyl group followed by treatment with NH3 to carbobenzoxy-L-isoglutamine, from which L-isoglutamine was obtained through hydrogenolysis. Direct amidation of p- toluenesulfonyl-L-aspartic anhydride yielded p-toluenesulfonyl-L-isoasparagine, which, ...
