21429-06-1Relevant academic research and scientific papers
Switching with orthogonal stimuli: Electrochemical ring-closure and photochemical ring-opening of bis(thiazolyl)maleimides
Herder, Martin,Utecht, Manuel,Manicke, Nicole,Grubert, Lutz,Paetzel, Michael,Saalfrank, Peter,Hecht, Stefan
, p. 1028 - 1040 (2013)
The photochemistry as well as electrochemistry of novel donor-acceptor bis(morpholinothiazolyl)-maleimides has been investigated. Proper substitution of these diarylethene-type molecular switches leads to the unique situation in which their ring-closure can only be accomplished electrochemically, while ring-opening can only be achieved photochemically. Hence, these switches operate with orthogonal stimuli, i.e. redox potential and light, respectively. The switch system could be optimized by introducing trifluoromethyl groups at the reactive carbon atoms in order to avoid by-product formation during oxidative ring closure. Both photochemical and electrochemical pathways were investigated for methylated, trifluoromethylated, and nonsymmetrical bis(morpholinothiazolyl) maleimides as well as the bis(morpholinothiazolyl)cyclopentene reference compound. With the aid of the nonsymmetrical mixed derivative, the mechanism of electrochemically driven ring closure could be elucidated and seems to proceed via a dicationic intermediate generated by two-fold oxidation. All experimental work has been complemented by density functional theory that provides detailed insights into the thermodynamics of the ring-open and closed forms, the nature of their excited states, and the reactivity of their neutral as well as ionized species in different electronic configurations. The particular diarylethene systems described herein could serve in multifunctional (logic) devices operated by different stimuli (inputs) and may pave the way to converting light into electrical energy via photoinduced pumping of redox-active meta-stable states.
Intriguing enigma of nitrobenzofuroxan's ‘Sphinx’: Boulton-Katritzky rearrangement or unusual evidence of theN-1/N-3-oxide rearrangement?
Boga, Carla,Bordoni, Silvia,Calvaresi, Matteo,Chugunova, Elena,Iannuzzo, Leonardo,Micheletti, Gabriele,Telese, Dario
, p. 34670 - 34680 (2020)
The SEAr/SNAr reaction between 7-chloro-4,6-dinitrobenzofuroxan (ClDNBF) and 2-morpholinyl-, 2-piperidinyl-, or 2-pyrrolidinylthiazole afforded unexpectedly two isomeric products, bearing the benzofuroxanyl moiety bound to the C-5 carbon atom of the thiazole ring. The relative ratio for the two isomers was dependent on temperature and solvent, suggesting the occurrence of an equilibrium between the two novel species. In order to investigate their structure and to design a plausible mechanistic pathway, a series of synthetic and spectroscopic experiments was planned. The isomer's structure was unambigously assigned when the reduction of furoxanyl to the furazanyl ring of the products gave exclusively a single species whose NMR data were coincident with those obtained by reacting the starting 2-aminothiazole derivatives with the 7-chloro-4,6-dinitrobenzofurazan (ClDNBZ). Possible mechanistic pathways might involveN-1-/N-3 oxide tautomerism or Boulton-Katritzky rearrangement and the current study is the first attempt to compare these two reactions. The data collected agree with the first one and DFT calculations permitted also a significant correlation with13C NMR experimental data and the assignment of the structure of each isomer. Finally, only one Meisenheimer intermediate for each electrophile/nucleophile combination was isolated by coupling the 2-aminothiazole derivatives with 4,6-dinitrobenzofuroxan (DNBF).
Copper- and Cobalt-Catalyzed Syntheses of Thiophene-Based Tertiary Amines
Bouarfa, Salima,Gra?l, Simon,Ivanova, Maria,Langlais, Timothy,Bentabed-Ababsa, Ghenia,Lassagne, Frédéric,Erb, William,Roisnel, Thierry,Dorcet, Vincent,Knochel, Paul,Mongin, Florence
, p. 3244 - 3258 (2019/06/08)
Thienylzinc halides and related compounds prepared by deprotonation followed by transmetalation were used in copper-catalyzed amination using N-benzoyloxy secondary amines. By extending the reaction to 1,5-naphthyridine, it was showed that the competitive dimer formation observed in the case of thiophenes was linked with the low stability of some thienylamines rather than homocoupling. Interestingly, thienylzinc halides and related compounds prepared by transmetalation of thienylmagnesium halides, either prepared from their bromo-precursors or generated by deprotometalation, were satisfactorily employed in cobalt-catalyzed aminations. Finally, aminothiophenes were involved in copper-catalyzed mono- and di-N-arylations, affording differently substituted di- and triphenylamines.
Solid Supported Nano Structured Cu-Catalyst for Solvent/Ligand Free C2 Amination of Azoles
Dutta, Pratip Kumar,Sen, Subhabrata,Saha, Debasree,Dhar, Basabbijayi
supporting information, p. 657 - 665 (2018/02/14)
Ligand- and solvent-free catalytic conditions that harness a nanostructured–CuI catalyst encapsulated in TiO2 has been reported for C2-amination of azoles (benzothiazole, benzoxazole and thiazole). The reaction is highly regioselective. The catalyst is robust, inexpensive and can be recycled up to four times. This strategy was further used for the synthesis of a small molecule with anti-HIV and anti-tumor properties.
Copper-catalyzed electrophilic amination of heteroarenes and arenes by C-H zincation
McDonald, Stacey L.,Hendrick, Charles E.,Wang, Qiu
supporting information, p. 4667 - 4670 (2014/05/20)
Direct amination of heteroarenes and arenes has been achieved in a one-pot C-H zincation/copper-catalyzed electrophilic amination procedure. This amination method provides an efficient and rapid approach to access a diverse range of heteroaromatic and aromatic amines including those previously inaccessible using C-H amination methods. The mild reaction conditions and good functional-group compatibility demonstrate its great potential for the synthesis of important and complex amines. Direct amination of heteroarenes and arenes has been achieved in a one-pot zincation/Cu(OAc)2-catalyzed amination sequence using O-acylhydroxylamines. The method provides a rapid and efficient approach to a range of aromatic and heteroaromatic amines, including those which were previously inaccessible by using C-H amination methods. tmp=2,2,6,6- tetramethylpiperidide.
Arylation of amines and monoarylation of symmetrical diamines in the presence of brine solution with diheteroaryl halides
Verma, Sanjeev K.,Ghorpade, Ramarao,Kaushik
supporting information, p. 2645 - 2655 (2014/08/18)
A simple, scalable, ligand-free, and metal-free protocol for arylation of amines and monoarylation of symmetrical diamines with diheteroaryl halides in the presence of brine solution has been developed. The protocol has broad structural applicability for chemoselective monoarylation of a wide variety of symmetrical, cyclic, and acyclic aliphatic diamines. The protocol is also applicable for selective arylation of aliphatic amine in the presence of aromatic amine.
A DBU-diheteroaryl halide adduct as the fastest current N-diheteroarylating agent
Verma, Sanjeev K.,Acharya,Ghorpade, Ramarao,Pratap, Ajay,Kaushik
, p. 18783 - 18786 (2013/10/22)
An unexpected diazabicyclo[5.4.0]undec-7-ene (DBU) catalysed rate enhancement of N-arylation of amines with diheteroaryl halides is reported. DBU is found to activate the Ar-Cl bond of a diheteroaryl halide, forming a green coloured adduct under neat conditions. The activated green coloured adduct was used for the arylation of amines under neat conditions and was found to be the fastest diheteroarylating agent reported to date. The Royal Society of Chemistry 2013.
Chemospecific and ligand free CuI catalysed heterogeneous N-arylation of amines with diheteroaryl halides at room temperature
Verma, Sanjeev K.,Acharya,Kaushik
supporting information; experimental part, p. 1324 - 1327 (2011/04/16)
A ligand free, copper-catalyzed N-arylation reaction of amines with diheteroaryl halides in heterogeneous medium at room temperature has been developed. The protocol is very effective for low boiling amines and useful for amines available in aqueous solution. The reaction gives chemospecific arylation of amines with diheteroaryl halides in the mixture monoheteroaryl halides, diheteroaryl halides and carbocyclic aryl halides. The reaction is also chemospecific with respect to arylation of aliphatic amines. Monoarylated piperazines were also synthesized at room temperature following this protocol. The Royal Society of Chemistry 2011.
BENZOXAZOLE DERIVATIVES
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Page/Page column 48-49, (2009/10/01)
It is intended to provide a benzoxazole derivative or a pharmaceutically acceptable salt or solvate thereof which is useful in the early diagnosis of a conformation disease; a composition or a kit containing the same for diagnosing a conformation disease; a medical composition for ttreating and/or preventing a conformation disease; and so on.
GLUCOCORTICOID MIMETICS, METHODS OF MAKING THEM, PHARMACEUTICAL COMPOSITIONS, AND USES THEREOF
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Page/Page column 178, (2008/12/06)
Compounds of Formula (IA) (IA), and Formula (IB) (IB), wherein R1, R2, R3, A, B, C, D, E, G, X, Y, and Z are as defined herein, or a tautomer, prodrug, solvate, or salt thereof; pharmaceutical compositions containing such compounds, and methods of modulating the glucocorticoid receptor function and methods of treating disease-states or conditions mediated by the glucocorticoid receptor function or characterized by inflammatory, allergic, or proliferative processes in a patient using these compounds.
