AMP deaminase inhibitors. 4. Further N3-substituted coformycin aglycon analogues: N3-alkylmalonates as ribose 5 '-monophosphate mimetics

AMP deaminase (AMPDA) inhibitors increase the levels of extracellular adeno sine and preserve intracellular adenylate pools in cellular models of ATP d epletion and therefore represent a potential new class of antiischemic drug s. Recently we reported that replacement of the ribose 5'-monophosphate com ponent of the very potent transition-state analogue AMPDA inhibitor coformy cin monophosphate (1) with a simple alkylcarboxy group resulted in potent, selective, and cell-penetrating AMPDA inhibitors. Here we report that repla cement of this alkylcarboxy group with an a-substituted alkylmalonic acid r esulted in enhanced inhibitor potency. The lead compound, 3-(5,5-dicarboxy- 6-(3-(trifluoromethyl)phenyl)-n-hexyl)coformation aglycon (21), exhibited a n AMPDA K-i of 0.029 mu M which is (3 x 10(5))-fold lower than the K-M for the natural substrate AMP. A comparison of inhibitory potencies shows that the diacid analogues with cr-benzyl substituents are 2-10-fold more inhibit ory than similar monoacid-monoester monoester-monoamide, or diester derivat ives. Finally, these diacid analogues are 2-40-fold more potent inhibitors than the corresponding monocarboxylates.