On the Formation of 3, 5, 8, 10- Tetraketoperhydrodipyrrolo [a, d] pyrazine by Melting of Glutamic Acid in Vacunm and the Isolation of N-Pyroglutamyl pyroglutamic Acid

Abstract

We have isolated a crystal and obtained fairly good yield by melting glutamic acid at 200° in vacuum under 30 mm Hg.
It gave a new crystal after recrystallization from hot water, under slow operation.
From the properties as described in Table 1, the former crystal was concluded to be 3, 5, 8, 10-tetraketoperhydrodipyrrolo [a, d] pyrazine, and the latter, N-pyroglutamyl pyroglutamic acid-a substance previously unreported.