Cyclic meso-ionic compounds. Part 21. The examination of nitro-derivatives of meso-ionic heterocycles as potential pharmaceuticals

Abstract

The synthesis of nitro-substituted meso-ionic compounds has been examined in an attempt to obtain analogues of the biologically active heterocycles (1)–(3). The synthesis of the compounds (4) and (5) has been achieved but their instability precluded biological evaluation. The synthesis of the type-B meso-ionic heterocycle (6) was not successfully completed, but unusual nucleophilic displacement reactions of the pyrazole (13)→(16)+(17) and the pyrazolium salt (14)→(15) are reported.