STRUCTURE OF THE (2-ACETAMIDOBENZOYL)FORMATE ANION AS THE BENZAMIDINIUM SALT

The reaction of isatin with benzamidine hydrochloride in methanol yiel ds the title compound, benzamidium (2-acetamidobenzoyl)formate (C7H9N2 +.C10H8NO4-). In the benzamidinium cation the configuration about the exocyclic C atoms is planar, resulting in electron delocalization in t he C-N bonds. The C-O bond distances in the carboxylate moeity in the anion are very similar (average C-O = 1.237 Angstrom), indicating delo calization of the negative charge. Hydrogen bonds are present between the N atoms of the amidinium group and the O atoms of the carboxylate moeity of the anion. The N O distances vary between 2.819 (5) and 2.90 1 (5) Angstrom in the hydrogen bonds.