- Para -C-H borylation of benzene derivatives by a bulky iridium catalyst
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A highly para-selective aromatic C-H borylation has been accomplished. By a new iridium catalyst bearing a bulky diphosphine ligand, Xyl-MeO-BIPHEP, the C-H borylation of monosubstituted benzenes can be affected with para-selectivity up to 91%. This catalytic system is quite different from the usual iridium catalysts that cannot distinguish meta- and para-C-H bonds of monosubstituted benzene derivatives, resulting in the preferred formation of meta-products. The para-selectivity increases with increasing bulkiness of the substituent on the arene, indicating that the regioselectivity of the present reaction is primarily controlled by steric repulsion between substrate and catalyst. Caramiphen, an anticholinergic drug used in the treatment of Parkinsons disease, was converted into five derivatives via our para-selective borylation. The present [Ir(cod)OH]2/Xyl-MeO-BIPHEP catalyst represents a unique, sterically controlled, para-selective, aromatic C-H borylation system that should find use in streamlined, predictable chemical synthesis and in the rapid discovery and optimization of pharmaceuticals and materials.
- Saito, Yutaro,Segawa, Yasutomo,Itami, Kenichiro
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p. 5193 - 5198
(2015/05/05)
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- Pharmaceutical compositions and methods for preventing, treating, or reversing neuronal dysfunction
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The present invention provides compositions and methods for preventing, treating or reversing neuronal dysfunction in a mammal resulting from exposure to organophosphate nerve agents, organophosphate insecticides and incapacitating agents of the central nervous system (CNS); CNS injury, including traumatic brain injury, neurologic complications of cardiac surgery, perinatal asphyxia, and stroke, spinal cord injury, and peripheral nerve injury; and neuronal disorders associated with the loss of motor function including post-polio syndrome, amyotrophic lateral sclerosis, myasthenia gravis, Parkinson's disease and Rett syndrome; neurodegenerative disorders including Alzheimer's disease, mild cognitive impairment and schizophrenia; and cognitive impairment associated with aging. The compositions of the invention preferably comprise in effective amounts (a) at least one acetylcholinesterase inhibitor, (b) at least one compound with anticholinergic properties or both anticholinergic and antiglutamatergic properties, (c) optionally an anticonvulsive compound, and a pharmaceutically acceptable carrier.
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