- Metal-Free Aminomethylation of Aromatic Sulfones Promoted by Eosin Y
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A metal-free α-aminomethylation of heteroaryls promoted by eosin Y under green light irradiation is reported. A large variety of α-trimethylsilylamines as precursor of α-aminomethyl radical species were engaged to functionalize sulfonyl-heteroaryls following a Homolytic Aromatic Substitution (HAS) pathway. This method has provided a range of α-aminoheteroaryl compounds including a functionalized natural product. The mechanism of this late-stage functionalization of aryls was investigated and suggests the formation of a sulfonyl radical intermediate over a reductive quenching cycle.
- Thierry, Thibault,Pfund, Emmanuel,Lequeux, Thierry
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supporting information
p. 14826 - 14830
(2021/10/01)
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- Novel heterocyclic analogues of firefly luciferin
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Five novel firefly luciferin analogues in which the benzothiazole ring system of the natural substrate was replaced with benzimidazole, benzofuran, benzothiophene, benzoxazole, and indole were synthesized. The fluorescence, bioluminescence, and kinetic pr
- Woodroofe, Carolyn C.,Meisenheimer, Poncho L.,Klaubert, Dieter H.,Kovic, Yumi,Rosenberg, Justin C.,Behney, Curran E.,Southworth, Tara L.,Branchini, Bruce R.
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p. 9807 - 9813
(2013/02/25)
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- Chemistry of covalent inhibition of the gastric (H+, K +)-ATPase by proton pump inhibitors
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Proton pump inhibitors (PPIs), drugs that are widely used for treatment of acid related diseases, are either substituted pyridylmethylsulfinyl benzimidazole of imidazopyridine derivatives. They are all prodrugs that inhibit the acid-secreting gastric (H+, K+)-ATPase by acid activation to reactive thiophiles that form disulfide bonds with one or more cysteines accessible from the exoplasmic surface of the enzyme. This unique acid-catalysis mechanism had been ascribed to the nucleophilicity of the pyridine ring. However, the data obtained here show that their conversion to the reactive cationic thiophilic sulfenic acid or sulfenamide depends mainly not on pyridine protonation but on a second protonation of the imidazole component that increases the electrophilicity of the C-2 position on the imidazole. This protonation results in reaction of the C-2 with the unprotonated fraction of the pyridine ring to form the reactive derivatives. The relevant PPI pK a's were determined by UV spectroscopy of the benzimidazole or imidazopyridine sulfinylmethyl moieties at different medium pH. Synthesis of a relatively acid stable analogue, N1-methyl lansoprazole, (6b), allowed direct determination of both pKa values of this intact PPI allowing calculation of the two pKa values for all the PPIs. These values predict their relative acid stability and thus the rate of reaction with cysteines of the active proton pump at the pH of the secreting parietal cell. The PPI accumulates in the secretory canaliculus of the parietal cell due to pyridine protonation then binds to the pump and is activated by the second protonation on the surface of the protein to allow disulfide formation.
- Shin, Jai Moo,Cho, Young Moon,Sachs, George
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p. 7800 - 7811
(2007/10/03)
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- 4-chloro-3,5-dimethyl-2-sulfonyl pyridines
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2-Sulfonylpyridine derivatives can be industrially produced efficiently by reacting a sulfonyl cyanide derivative with an α,β-unsaturated carbonyl compound and a 2-{[(2-pyridyl)methyl]thio}-1H-benzimidazole skeleton can be formed in one step in a good yield by reacting this type of the 2-sulfonylpyridine derivative with a 2-methylthio-1H-benzimidazole derivative in the presence of an organolithium compound.
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Referential example 1
(2010/11/29)
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- Method for producing 2-sulfonylpyridine derivatives and method for producing 2-{[(2-pyridyl)methyl]thio}-1H-benzimidazole derivatives
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2-Sulfonylpyridine derivatives can be industrially produced efficiently by reacting a sulfonyl cyanide derivative with an α, β-unsaturated carbonyl compound and a 2-{[(2-pyridyl)methyl]thio}-1H-benzimidazole skeleton can be formed in one step in a good yield by reacting this type of the 2-sulfonylpyridine derivative with a 2-methylthio-1H-benzimidazole derivative in the presence of an organolithium compound.
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