Abstract: Twenty three glutamine derivatives (5-N-substituted amides and 5-alkylesters of phthalimido-α-aminoglutarid acid) were synthesized for anticancer and glutaminase inhibitory tests. These compounds were prepared from a-phthalimido-glutaric anhydride and appropriate amines and alcohols. The phthalyl group was removed by hydrolysis with aqueous hydrazine hydrate and sodium carbonate solution. Compound I₈ shows significant inhibitory activity against S 180 and several other animal tumors, while compounds I_1,2,5,7-10 inhibit the activity of glutaminase. On the contrary, compounds of type II are inactive.