Crystallization, structural study and analysis of intermolecular interactions of a 2-aminobenzoxazole–fumaric acid molecular salt

Abstract

The new organic salt, 2-aminobenzoxazol-3-ium 3-carboxyprop-2-enoate, C7H7N2O+·C4H3O4 −, of the two bioactive compounds 2-aminobenzoxazole and fumaric acid, crystallizes in the orthorhombic space group Pbca using classical evaporation of their solution in water. The usual topological analysis revealed four classical (N—H...O and O—H...O) and two non-classical (C—H...O) hydrogen bonds in the structure. Stacking was found as well for a pair of 2-aminobenzoxazolium cations. A Hirshfeld surface analysis including the two-dimensional fingerprint plots was performed to define the residual π–π interactions and to quantify the influences of different types of interactions by means of topological analysis. Analysis of the pairwise interaction energies was used to prove the formation of the corrugated paired layers of cation–anion dimers parallel to the plane (001) as a basic structural motif in the topological, as well as in the energetic structure of the crystal. It showed that the layers are connected by the hydrogen bonds inside and by stacking and π–π interactions and general dispersion between them.

2-Aminobenzoxazole–oxalic acid (2/1)

“…The geometric parameters of the arene and oxazole rings are similar to standard values and to those in other related structures (Ashurov et al, 2011(Ashurov et al, , 2015Wang et al, 2016). In the oxalate (OXL) part of the organic salt, two hydrogen atoms are transferred to the nitrogen of the oxazole fragments, as in other 2-aminobenzoxazole (2ABO) structures (Nandy et al, 2016;Razzoqova et al, 2022Razzoqova et al, , 2023. As a result, the 2ABO and OXL ions form two closed eight-membered rings with an R 2 2 (8) graph-set notation (Etter et al, 1990).…”

Synthesis, structure and Hirshfeld surface analysis of a coordination compound of cadmium acetate with 2-aminobenzoxazole

“…An analysis of the Cambridge Structural Database (CSD, Version 5.43, update of March 2022; Groom et al, 2016) showed that there are no X-ray structures of 2AB and its metal complexes in the database. However, recently, we reported the structure and intermolecular interactions of a 2AB-fumaric acid organic salt in which the N atom of 2AB is protonated by a fumaric acid H atom (Razzoqova et al, 2022). Theoretically, metal complexes of 2AB may involve coordination through the N or O atoms of the oxazole ring and the N atom of the amino substituent.…”

“…Although benzoxazole itself is of little practical interest, many benzoxazole derivatives are commercially important. They play an important role in medicinal and biological chemistry (Potashman et al, 2007;Lachtova et al, 2018;Razzoqova et al, 2022), being described as potential therapeutic agents, including as various enzyme inhibitors (Chikhale et al, 2018). Aminobenzoxazoles, in particular derivatives of 2-aminobenzoxazole (2AB), have anticancer and antibacterial properties (Khajondetchairit et al, 2017;Ouyang et al, 2012).…”