- REAGENTS AND PROCESS FOR DIRECT C-H FUNCTIONALIZATION
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Thianthrene derivative of the Formula (I): wherein R1 to R8 may be the same or different and are selected from hydrogen, Cl, F, a partially or fully fluorinated C1 to C6 alkyl group, and wherein n is 0 or 1, with the proviso that at least one of R1 to R8 is not hydrogen and process for C-H functionalization of aromatic compounds using this compound.
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Page/Page column 94; 95
(2020/06/01)
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- Photoredox catalysis with aryl sulfonium salts enables site-selective late-stage fluorination
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Photoredox catalysis, especially in combination with transition metal catalysis, can produce redox states of transition metal catalysts to facilitate challenging bond formations that are not readily accessible in conventional redox catalysis. For arene functionalization, metallophotoredox catalysis has successfully made use of the same leaving groups as those valuable in conventional cross-coupling catalysis, such as bromide. Yet the redox potentials of common photoredox catalysts are not sufficient to reduce most aryl bromides, so synthetically useful aryl radicals are often not directly available. Therefore, the development of a distinct leaving group more appropriately matched in redox potential could enable new reactivity manifolds for metallophotoredox catalysis, especially if arylcopper(iii) complexes are accessible, from which the most challenging bond-forming reactions can occur. Here we show the conceptual advantages of aryl thianthrenium salts for metallophotoredox catalysis, and their utility in site-selective late-stage aromatic fluorination.
- Li, Jiakun,Chen, Junting,Sang, Ruocheng,Ham, Won-Seok,Plutschack, Matthew B.,Berger, Florian,Chabbra, Sonia,Schnegg, Alexander,Genicot, Christophe,Ritter, Tobias
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- Synthesis and biological evaluation of novel 2,4-diaminoquinazoline derivatives as SMN2 promoter activators for the potential treatment of spinal muscular atrophy
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Proximal spinal muscular atrophy (SMA) is an autosomal recessive disorder characterized by death of motor neurons in the spinal cord that is caused by deletion and/or mutation of the survival motor neuron gene (SMN1). Adjacent to SMN1 are a variable number of copies of the SMN2 gene. The two genes essentially differ by a single nucleotide, which causes the majority of the RNA transcripts from SMN2 to lack exon 7. Although both SMN1 and SMN2 encode the same Smn protein amino acid sequence, the loss of SMN1 and incorrect splicing of SMN2 have the consequence that Smn protein levels are insufficient for the survival of motor neurons. The therapeutic goal of our medicinal chemistry effort was to identify small-molecule activators of the SMN2 promoter that, by up-regulating gene transcription, would produce greater quantities of full-length Smn protein. Our initial medicinal chemistry effort explored a series of C5 substituted benzyl ether based 2,4-diaminoquinazoline derivatives that were found to be potent activators of the SMN2 promoter; however, inhibition of DHFR was shown to be an off-target activity that was linked to ATP depletion. We used a structure-guided approach to overcome DHFR inhibition while retaining SMN2 promoter activation. A lead compound 11a was identified as having high potency (EC50 = 4 nM) and 2.3-fold induction of the SMN2 promoter. Compound 11a possessed desirable pharmaceutical properties, including excellent brain exposure and long brain half-life following oral dosing to mice. The piperidine compound 11a up-regulated expression of the mouse SMN gene in NSC-34 cells, a mouse motor neuron hybrid cell line. In type 1 SMA patient fibroblasts, compound 11a induced Smn in a dose-dependent manner when analyzed by immunoblotting and increased the number of intranuclear particles called gems. The compound restored gems numbers in type I SMA patient fibroblasts to levels near unaffected genetic carriers of SMA.
- Thurmond, John,Butchbach, Matthew E. R.,Palomo, Marty,Pease, Brian,Rao, Munagala,Bedell, Louis,Keyvan, Monica,Pai, Grace,Mishra, Rama,Haraldsson, Magnus,Andresson, Thorkell,Bragason, Gisli,Thosteinsdottir, Margret,Bjornsson, Jon Mar,Coovert, Daniel D.,Burghes, Arthur H. M.,Gurney, Mark E.,Singh, Jasbir
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p. 449 - 469
(2008/09/18)
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