- Aminomethylation of Aryl Bromides by Nickel-Catalyzed Electrochemical Redox Neutral Cross Coupling
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We develop an electrochemical nickel-catalyzed aminomethylation of aryl bromides under mild conditions. The convergent paired electrolysis makes full use of anode and cathode processes, free of a terminal oxidant, a sacrificial anode, a metal reductant, and a prefunctionalized radical precursor. In addition, this method exhibits wide functional group tolerance (63 examples), including some sensitive substituents and aromatic heterocycles. This redox neutral cross coupling provides a more environmentally friendly and synthetic practical protocol for forging C(sp2)–C(sp3) bonds.
- Ma, Yueyue,Hong, Jufei,Yao, Xiantong,Liu, Chengyu,Zhang, Ling,Fu, Youtian,Sun, Maolin,Cheng, Ruihua,Li, Zhong,Ye, Jinxing
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supporting information
p. 9387 - 9392
(2021/12/17)
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- A curcumin-based molecular probe for near-infrared fluorescence imaging of tau fibrils in Alzheimer's disease
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In recent years, there has been growing interest in the near-infrared (NIR) fluorescence imaging of tau fibrils for the early diagnosis of Alzheimer's disease (AD). In order to develop a curcumin-based NIR fluorescent probe for tau fibrils, structural modification of the curcumin scaffold was attempted by combining the following rationales: the curcumin derivative should preserve its binding affinity to tau fibrils, and, upon binding to tau fibrils, the probe should show favorable fluorescence properties. To meet these requirements, we designed a novel curcumin scaffold with various aromatic substituents. Among the series, the curcumin derivative 1c with a (4-dimethylamino-2,6-dimethoxy)phenyl moiety showed a significant change in its fluorescence properties (22.9-fold increase in quantum yield; Kd, 0.77 μM; λem, 620 nm; Φ, 0.32) after binding to tau fibrils. In addition, fluorescence imaging of tau-green fluorescent protein-transfected SHSY-5Y cells with 1c confirmed that 1c detected tau fibrils in live cells.
- Park, Kwang-Su,Seo, Yujin,Kim, Mi Kyoung,Kim, Kyungdo,Kim, Yun Kyung,Choo, Hyunah,Chong, Youhoon
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supporting information
p. 11194 - 11199
(2015/11/27)
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- Copper-free sonogashira cross-coupling for functionalization of alkyne-encoded proteins in aqueous medium and in bacterial cells
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Bioorthogonal reactions suitable for functionalization of genetically or metabolically encoded alkynes, for example, copper-catalyzed azide-alkyne cycloaddition reaction ("click chemistry"), have provided chemical tools to study biomolecular dynamics and function in living systems. Despite its prominence in organic synthesis, copper-free Sonogashira cross-coupling reaction suitable for biological applications has not been reported. In this work, we report the discovery of a robust aminopyrimidine-palladium(II) complex for copper-free Sonogashira cross-coupling that enables selective functionalization of a homopropargylglycine (HPG)-encoded ubiquitin protein in aqueous medium. A wide range of aromatic groups including fluorophores and fluorinated aromatic compounds can be readily introduced into the HPG-containing ubiquitin under mild conditions with good to excellent yields. The suitability of this reaction for functionalization of HPG-encoded ubiquitin in Escherichia coli was also demonstrated. The high efficiency of this new catalytic system should greatly enhance the utility of Sonogashira cross-coupling in bioorthogonal chemistry.
- Li, Nan,Lim, Reyna K. V.,Edwardraja, Selvakumar,Lin, Qing
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supporting information; experimental part
p. 15316 - 15319
(2011/11/11)
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- Titanium Catalyzed Reduction of Aromatic Halides by Sodium Borohydride
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The reduction of aryl halides by sodium borohydride is catalyzed by titanium complexes; di(cyclopentadienyl)titanium dichloride (titanocence dichloride) is highly effective.The reaction scope and mechanism are solvent dependent.In dimethylformamide (DMF), an adduct of DMF and sodium borohydride is formed which reduces simple aryl halides by a non-radical, likely nucleophilic route.Dimethylamino- substituted products are formed, as are simple dechlorinated species.In dimethylacetamide or in ethers, a radical-based reaction involving activated titanocene borohydride takes place, and only dechlorinated products result.
- Liu, Yumin,Schwartz, Jeffrey
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p. 4471 - 4482
(2007/10/02)
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- Benzylideneamino- and phenylacetylguanidines and their pharmaceutical uses
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Compounds of formula (I): STR1 or a salt or acyl derivative thereof; wherein Y is either --CH=N or STR2 R1 is hydroxy, halogen, (C1-4) alkyl, or (C1-4)alkoxy, R2 is a nitrogen-containing, basic substituent, R3 is hydrogen, hydroxy, halogen, (C1-4) alkyl, (C1-4) alkoxy or a nitrogen-containing, basic substituent, and R4 is hydrogen or hydroxy, are useful in treating diarrhoea and scours.
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- Amphetamine derivatives
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Compounds having the general formula STR1 or pharmaceutically acceptable salts thereof, in which formula R1 and R2 are the same or different and each represents a hydrogen atom, a lower alkyl group or a halogen atom, R3 represents a lower alkyl group or a benzyl group, R4 represents a hydrogen atom, a lower alkyl group, a benzyl group or a CH2 CH2 CH2 --bridge connected to the phenyl ring in ortho-position relative to the N-substituent, R5 represents a hydrogen atom or a methyl group and R6 represents a lower alkyl group, provided that R1 and/or R2 represents a lower alkyl group or a halogen atom when R3 represents a methyl group, R4 represents a methyl group and R5 represents a hydrogen atom; methods for the preparation thereof; intermediates useful for their preparation; pharmaceutical preparations containing at least one of these compounds; and the use thereof in the treatment of depressive states and alleviating anxiety.
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