CRYSTALLINE D-ISOGLUTAMYL-D-TRYPTOPHAN AND THE MONO AMMONIUMSALT OF D-ISOGLUTAMYL-D-TRYPTOPHAN

摘要

A process for making pure crystalline D-isoglutamyl-D-tryptophan is provi ded which includes the step of deprotecting essentially pure N-tert-butoxyca rbonyl-D- isoglutamyl-D-tryptophan or its diester to yield essentially pure D-isoglutamyl-D- tryptophan. A process is also provided for the preparation of pure mono ammonium salt of D-isoglutamyl-D-tryptophan from essentially pu re N-tert-butoxycarbonyl-D- isoglutamyl-D-tryptophan. D-isoglutamyl-D-trypto phan, ammonium salt (1 :1) is a stable pharmaceutical solid.