Synthesis and SAR studies of benzimidazolone derivatives as histamine H3-receptor antagonists

Synthesis of unsymmetrical 1,3-substituted-1,3-dihydro-benzimidazolones via copper-catalyzed C–N coupling under visible light

Although photoinduced copper catalysis for carbon–nitrogen (C–N) amine bond formation with alkyl/aryl halides has been developed, the potential of copper photocatalysis for the synthesis of 1,3-substituted benzimidazolones remains mostly unexplored.

Synthesis of exo-Imidazolidin-2-one Dienes, Their Isomerization, and Selectivity in Diels-Alder Cycloadditions

An efficient and alternative synthesis of exo-imidazolidin-2-one dienes is described. A condensation reaction was carried out with bis-imino derivatives, diacetyl, and triphosgene, affording symmetrically N, N-disubstituted dienes. The use of alkyl methyl α-diketones led to the formation of nonsymmetrical dienes, which underwent isomerization to provide more stable inner-outer-ring dienes under Lewis acid conditions. Evaluation was made of the reactivity as well as regio- and stereoselectivity of these dienes in Diels-Alder reactions. They proved to be highly reactive and selective. DFT calculations of the transition states accounted for their behavior.

Investigating the geometrical preferences of a flexible benzimidazolone-based linker in the synthesis of coordination polymers

A series of new group 2 coordination polymers, MgL ={MgL(H₂O)(DMF)_0.75}_∞, CaL = {CaL(DMF)₂}_∞, SrL = {SrL(H₂O)_0.5}_∞ and BaL = {BaL(H₂O)_0.5}_∞, were synthesized using a flexible benzimidazolone diacetic acid linker (H₂L) in which the two carboxylic acid binding sites are connected to a planar core via {-CH₂-} spacers that can freely rotate in solution. In a 'curiosity-led' diversion from group 2 metals, the first row transition metal salts Mn²⁺, Cu²⁺ and Zn²⁺ were also reacted with L to yield crystals of MnL = {MnL(DMF)(H₂O)_3.33}_∞, Cu₃L₂  = {Cu₃L₂(DMF)₂(CHO₂)₂}_∞ and ZnL = {ZnL(DMF)}_∞. Crystal structures were obtained for all seven materials. All structures form as two-dimensional sheets and contain six-coordinate centres, with the exception of ZnL, which displays tetrahedrally coordinated metal centres, and Cu₃L₂ , which contains square planar coordinated metal centres and Cu paddle-wheels. In each structure, the linker adopts one of two distinct conformations, with the carboxylate groups either cis or trans with respect to the planar core. All materials were also characterized by powder X-ray diffraction and thermogravimetric analysis.