Synthesis, Antimicrobial and Cholinesterase Enzymes Inhibitory Activities of Indeno Imidazoles and X-Ray Crystal Structure of 3a,8a-Dihydroxy-1,3-diphenyl-1,3,3a,8a-tetrahydro-indeno[1,2-d]imidazole-2,8-dione

Two indeno imidazoles have been synthesized by the reaction of ninhydrin with diphenylurea and diphenylthiourea. The structures have been determined by spectral analysis. The supramolecular behavior of 3a,8a-Dihydroxy-1,3-diphenyl-1,3,3a,8a-tetrahydro-indeno[1,2-d]imidazole-2,8-dione (1) was thoroughly analyzed and reported using X-ray single crystal technique and concepts. The presence of oxygen and nitrogen atoms led to very interesting supramolecular motifs interactions such as nitrogen-oxygen, nitrogen-nitrogen, oxygen-oxygen, nitrogen-hydrogen, and oxygen-hydrogen. 3a,8a-dihydroxy-1,3-diphenyl-2-thioxo-2,3,3a,8a-tetrahydro-1H-indeno[1,2-d]imidazol-8-one 2 showed good antibacterial activity against B. subtilis and P. aeruginosa, while 3a,8a-dihydroxy-1,3-diphenyl-1,3,3a,8a-tetrahydro-indeno[1,2-d]imidazole-2,8-dione 1 only showed antibacterial activity against P. aeruginosa. Both of 1 and 2 were inactive against C. albicans. Derivative 2 demonstrated good cholinesterase enzyme activity unlike derivative 1 which has weak inhibitory activity against these enzymes. Furthermore, 2 was found to be a selective butyrylcholinesterase enzyme inhibitor that has potential use for prevention of further neurodegeneration as well for symptomatic treatment of Alzheimer patients. The non-covalent interactions involved in the crystal structure of 3a,8a-Dihydroxy-1,3-diphenyl-1,3,3a,8a-tetrahydro-indeno[1,2-d]imidazole-2,8-dione (1) were investigated and reported in terms of crystal engineering and supramolecular chemistry. Different motifs of N center dot center dot center dot H and O center dot center dot center dot H interactions as well as N center dot center dot center dot O, N center dot center dot center dot N, and O center dot center dot center dot O are adopted by the crystal structure and led to a strong crystal packing.