Synthesis of a coronene analogue containing an amide bond by Pd-mediated intramolecular C C bond formation of 2-halogenated 4-(alkylamino)benzoic acid cyclic trimer

Synthesis of a Cyclic Hexaamide Consisting of a Brominated m-Phenylene Repeating Unit

Aiming to synthesize a cyclic hexaamide, 4-bromo-3-(isobutylamino)benzoic acid was subjected to self-condensation reactions in the presence of either dichlorotriphenylphosphorane in 1,1,2,2-tetrachloroethane or tetrachlorosilane in pyridine. However, instead of the targeted cyclic hexaamide, the cyclic triamide and the cyclic tetraamide were obtained. The cyclic hexaamide was successfully synthesized via the self-condensation of the dimer, which was synthesized in five steps from 4-bromo-3-(isobutylamino)benzoic acid. A thorough screening of the self-condensation conditions was performed to improve the yield of the target macrocycle. In addition, the linear hexamer was synthesized by stepwise deprotection and condensation, and its cyclization afforded the cyclic hexaamide in good yield.

Synthesis, crystal structure, and properties of methyl-substituted coronene amide analogue

A coronene amide analogue was synthesized in six steps using an improved method at the final biarylation step. The key to the progress of palladium-mediated biarylation involved the introduction of three methyl groups to suppress the undesired reaction and the use of tri-tert-butylphosphine as the ligand for palladium. Single-crystal X-ray analysis revealed that the core unit of the coronene analogue has a non-planar structure.

The palladium-mediated intramolecular biarylation of the cyclic triamide of 2-bromo-4-(isobutylamino)benzoic acid proceeded effectively by the introduction of three methyl groups and the use of tri-tert-butylphosphine as the ligand.