1571-08-0Relevant academic research and scientific papers
Cobalt Corroles as Electrocatalysts for Water Oxidation: Strong Effect of Substituents on Catalytic Activity
Neuman, Nicolás I.,Albold, Uta,Ferretti, Eleonora,Chandra, Shubhadeep,Steinhauer, Simon,R?ner, Paul,Meyer, Franc,Doctorovich, Fabio,Vaillard, Santiago E.,Sarkar, Biprajit
, p. 16622 - 16634 (2020)
Two Co(III) complexes (1Py2 and 2Py2) of new corrole ligands H3L1 (5,15-bis(p-methylcarboxyphenyl)-10-(o-methylcarboxyphenyl)corrole) and H3L2 (5,15-bis(p-nitrophenyl)-10-(o-methylcarboxyphenyl)corrole) with two apical pyridine ligands have been synthesized and thoroughly characterized by cyclic voltammetry, UV-vis-NIR, and EPR spectroscopy, spectroelectrochemistry, single-crystal X-ray diffraction studies, and DFT methods. Complexes 1Py2 and 2Py2 possess much lower oxidation potentials than cobalt(III)-tris-pentafluorophenylcorrole (Co(tpfc)) and similar corroles containing pentafluorophenyl (C6F5) substituents, thus allowing access to high oxidation states of the former metallocorroles using mild chemical oxidants. The spectroscopic (UV-vis-NIR and EPR) and electronic properties of several oxidation states of these complexes have been determined by a combination of the mentioned methods. Complexes 1Py2 and 2Py2 undergo three oxidations within 1.3 V vs FcH+/FcH in MeCN, and we show that both complexes catalyze water oxidation in an MeCN/H2O mixture upon the third oxidation, with kobs (TOF) values of 1.86 s-1 at 1.29 V (1Py2) and 1.67 s-1 at 1.37 V (2Py2). These values are five times higher than previously reported TOF values for C6F5-substituted cobalt(III) corroles, a finding we ascribe to the additional charge in the corrole macrocycle due to the increased oxidation state. This work opens up new possibilities in the study of metallocorrole water oxidation catalysts, particularly by allowing spectroscopic probing of high-oxidation states and showing strong substituent-effects on catalytic activity of the corrole complexes.
Design, synthesis and pharmacological evaluation of N-benzyl-piperidinyl-aryl-acylhydrazone derivatives as donepezil hybrids: Discovery of novel multi-target anti-alzheimer prototype drug candidates
Dias Viegas, Flávia Pereira,de Freitas Silva, Matheus,Divino da Rocha, Miguel,Castelli, Maísa Rosa,Riquiel, Mariana Máximo,Machado, Rafael Pereira,Vaz, Sarah Macedo,Sim?es de Lima, Laís Medeiros,Mancini, Karla Cristine,Marques de Oliveira, Patrícia Cruz,Morais, élida Parreira,Gontijo, Vanessa Silva,da Silva, Fernanda Motta R.,D'Alincourt da Fonseca Pe?anha, Dora,Castro, Newton Gon?alves,Neves, Gilda A.,Giusti-Paiva, Alexandre,Vilela, Fabiana Cardoso,Orlandi, Lidiane,Camps, Ihosvany,Veloso, Márcia Paranho,Leomil Coelho, Luis Felipe,Ionta, Marisa,Ferreira-Silva, Guilherme álvaro,Pereira, Rodrigo Machado,Dardenne, Laurent E.,Guedes, Isabella Alvim,de Oliveira Carneiro Junior, Wellerson,Quaglio Bellozi, Paula Maria,Pinheiro de Oliveira, Ant?nio Carlos,Ferreira, Fábio Furlan,Pruccoli, Letizia,Tarozzi, Andrea,Viegas, Claudio
, p. 48 - 65 (2018)
A new series of sixteen multifunctional N-benzyl-piperidine-aryl-acylhydrazones hybrid derivatives was synthesized and evaluated for multi-target activities related to Alzheimer's disease (AD). The molecular hybridization approach was based on the combination, in a single molecule, of the pharmacophoric N-benzyl-piperidine subunit of donepezil, the substituted hydroxy-piperidine fragment of the AChE inhibitor LASSBio-767, and an acylhydrazone linker, a privileged structure present in a number of synthetic aryl- and aryl-acylhydrazone derivatives with significant AChE and anti-inflammatory activities. Among them, compounds 4c, 4d, 4g and 4j presented the best AChE inhibitory activities, but only compounds 4c and 4g exhibited concurrent anti-inflammatory activity in vitro and in vivo, against amyloid beta oligomer (AβO) induced neuroinflammation. Compound 4c also showed the best in vitro and in vivo neuroprotective effects against AβO-induced neurodegeneration. In addition, compound 4c showed a similar binding mode to donepezil in both acetylated and free forms of AChE enzyme in molecular docking studies and did not show relevant toxic effects on in vitro and in vivo assays, with good predicted ADME parameters in silico. Overall, all these results highlighted compound 4c as a promising and innovative multi-target drug prototype candidate for AD treatment.
Electronic and electrochemical properties as well as flowerlike supramolecular assemblies of fulleropyrrolidines bearing ester substituents with different alkyl chain lengths
Zhang, Xuan,Li, Xu-Dong,Ma, Li-Xia,Zhang, Bei
, p. 60342 - 60348 (2014)
A series of alkyl (methyl, ethyl, propyl, butyl) benzoate ester substituted fulleropyrrolidine derivatives (FP1-FP4) were synthesized and their electronic and electrochemical properties were investigated by means of absorption spectra, electronic structure calculation, and cyclic voltammetry (CV), respectively. The LUMO-HOMO energies and energy gaps of fullerene derivatives were estimated by the first reduction potential measured with CV combined with absorption spectra, which are consistent with those obtained from density functional theory (DFT) calculations. It was found that all fulleropyrrolidines showed very similar absorption spectra, orbital energies and redox behaviors, which are comparable with those of well-known phenyl-C61-butyric acid methyl ester (PCBM). The flowerlike supramolecular architectures obtained from the self-assembly of FP1-FP4 in chloroform-alcohol mixture solvents were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). A lamellar structure with a d-spacing of 1.92-2.02 nm that depends on the molecular size, corresponding to the thickness of a bilayer structure, suggested a face-to-face conformation of the substituent of C60 and an interdigitation of the bare C60 side packing. These fulleropyrrolidines have high C60 content, are energetically PCBM-like, and are capable of forming complex flowerlike architectures, which provide fundamental insights into molecular design toward advanced fullerene materials.
One-pot conversion of activated alcohols into terminal alkynes using manganese dioxide in combination with the Bestmann-Ohira reagent
Quesada, Ernesto,Taylor, Richard J.K.
, p. 6473 - 6476 (2005)
The direct conversion of activated primary alcohols into terminal alkynes through a sequential one-pot, two-step process involving oxidation with manganese dioxide and then treatment with the Bestmann-Ohira reagent is described. This transformation proceeds efficiently (59-99% yield) under mild reaction conditions with a range of benzylic, heterocyclic and propargylic alcohols. A tandem variant is also described, which is successful only with highly activated substrates.
Endosome Targeting meso-Tetraphenylchlorin-Chitosan Nanoconjugates for Photochemical Internalization
Gaware, Vivek S.,H?kerud, Monika,Juzeniene, Asta,H?gset, Anders,Berg, Kristian,Másson, Már
, p. 1108 - 1126 (2017)
Four amphiphilic covalently linked meso-tetraphenylchlorin-chitosan nanoconjugates were synthesized and evaluated for use in photochemical internalization (PCI) in vitro and in vivo. The synthetic protocol for the preparation of two different hydrophobic chlorin photosensitizers, 5-(4-aminophenyl)-10,15,20-triphenylchlorin and 5-(4-carboxyphenyl)-10,15,20-triphenylchlorin, was optimized. These monofunctional photosensitizers were covalently attached to carrier chitosan via silyl-protected 3,6-di-O-tert-butyldimethylsilyl-chitosan (Di-TBDMS-chitosan) with 0.10 degree of substitution per glucosamine (DS). Hydrophilic moieties such as trimethylamine and/or 1-methylpiperazine were incorporated with 0.9 DS to give fully water-soluble conjugates after removal of the TBDMS groups. A dynamic light scattering (DLS) study confirmed the formation of nanoparticles with a 140-200 nm diameter. These nanoconjugates could be activated at 650 nm (red region) light, with a fluorescence quantum yield (ΦF) of 0.43-0.45, and are thus suitable candidates for use in PCI. These nanoconjugates were taken up and localized in the endocytic vesicles of HCT116/LUC human colon carcinoma cells, and upon illumination they substantially enhanced plasmid DNA transfection. The nanoconjugates were also evaluated in preliminary in vivo experiments in tumor-bearing mice, showing that the nanoconjugates could induce a strong photodynamic therapy (PDT) and also PCI effects in treatment with bleomycin.
Synthesis of Carboxamide-Containing Tranylcypromine Analogues as LSD1 (KDM1A) Inhibitors Targeting Acute Myeloid Leukemia
Teresa Borrello, Maria,Benelkebir, Hanae,Lee, Adam,Hin Tam, Chak,Shafat, Manar,Rushworth, Stuart A.,Bowles, Kristian M.,Douglas, Leon,Duriez, Patrick J.,Bailey, Sarah,Crabb, Simon J.,Packham, Graham,Ganesan
, p. 1316 - 1324 (2021)
Lysine-specific demethylase 1 (LSD1/KDM1A) oxidatively removes methyl groups from histone proteins, and its aberrant activity has been correlated with cancers including acute myeloid leukemia (AML). We report a novel series of tranylcypromine analogues with a carboxamide at the 4-position of the aryl ring. These compounds, such as 5 a and 5 b with benzyl and phenethylamide substituents, respectively, had potent sub-micromolar IC50 values for the inhibition of LSD1 as well as cell proliferation in a panel of AML cell lines. The dose-dependent increase in cellular expression levels of H3K4me2, CD86, CD11b and CD14 supported a mechanism involving LSD1 inhibition. The tert-butyl and ethyl carbamate derivatives of these tranylcypromines, although inactive in LSD1 inhibition, were of similar potency in cell-based assays with a more rapid onset of action. This suggests that carbamates can act as metabolically labile tranylcypromine prodrugs with superior pharmacokinetics.
Synthesis and properties of a meso- tris-ferrocene appended zinc(ii) porphyrin and a critical evaluation of its dye sensitised solar cell (DSSC) performance
Sirbu,Turta,Benniston,Abou-Chahine,Lemmetyinen,Tkachenko,Wood,Gibson
, p. 22733 - 22742 (2014)
A zinc(ii) porphyrin derivative, F3P, was prepared containing a single ferrocene group appended at three of the meso positions. The final meso position contains a benzoic acid unit, and was designed to be an anchoring moiety to a semiconductor surface. The cyclic voltammogram for the porphyrin derivative reveals that the three ferrocene units are oxidised and reduced at E 1/2 = +0.04 V vs. Fc+/Fc. Other redox responses are porphyrin-based at +1.1 V vs. Fc+/Fc (irreversible) and -1.87 V and -2.20 V vs. Fc+/Fc (both quasi-reversible). The room temperature Moessbauer spectrum for F3P comprises a doublet (δ Fe 0.44 mm s -1; ΔEQ 2.35 mm s-1; peak width 0.27 mm s-1). The data are consistent with the ferrocene groups non-interacting with the porphyrin moiety in the ground state. Excitation of the compound in THF with an ultra-short laser pulse produces in less than 1 ps the charge separated state which comprises Fc+-porp- and decays back to the ground state in 24 ps. Roughly the same behaviour is observed for the dye absorbed on TiO2, the only slight difference is the appearance of a long-lived component in the decay records. The electron for the porphyrin radical anion does not inject into the conduction band of the TiO 2, only the porphyrin excited state participates in any electron injection process. Partly because of this factor the performance of the dye attached to TiO2 in a DSSC device is rather limited (JSC = 0.068 mA cm-2, VOC = 283 mV, FF = 0.42, η = 0.008%). This journal is the Partner Organisations 2014.
Highly atom efficient synthesis of 2,2,4,5-tetrasubstituted 3(2H)-furanones having both hydroxyl and amino substituents
Antony, Jesna,Mathai, Sindhu,Natarajan, Rakesh,P. Musthafa, Sumi,Rappai, John P.,S. Devaky, Karakkattu
supporting information, (2022/02/25)
We have developed a highly atom efficient synthesis of tetrasubstituted 3(2H)-furanones from easily accessible starting materials such as C,N-diarylaldonitrones and dibenzoylacetylene. Control experiments revealed that reaction of aldonitrones having electron-withdrawing groups on the C-aryl substituent in polar aprotic solvents exhibited high product selectivity while reaction temperature has only a negligible effect on product yield and selectivity.
Hydroxyl radical-mediated oxidative cleavage of CC bonds and further esterification reaction by heterogeneous semiconductor photocatalysis
Hong, Mei,Jia, Rui,Miao, Hongyan,Ni, Bangqing,Niu, Tengfei,Wang, Hui
, p. 6591 - 6597 (2021/09/10)
A hydroxyl radical-mediated aerobic cleavage of alkenes and further sequence esterification reaction for the preparation of carbonyl compounds have been developed by using tubular carbon nitride (TCN) as a general heterogeneous photocatalyst under an oxygen atmosphere with visible light irradiation. This protocol has an excellent substrate scope and gives the desired aldehydes, ketones and esters in moderate to high yields. Importantly, this metal-free procedure employed photogenerated hydroxyl radicals in situ as green oxidation active species, avoiding the present additional initiators. The reaction could be carried out under solar light irradiation and was applicable to large-scale reactions. Furthermore, the recyclable TCN catalyst could be used several times without a significant loss of activities.
New method for promoting photosensitive oxidation to remove 1, 2-mercaptoethanol acetal protecting group by utilizing visible light irradiation
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Paragraph 0014-0016, (2021/01/30)
The invention discloses a new method for removing a 1, 2-mercaptoethanol acetal protecting group, and belongs to the field of organic synthetic chemistry. The method comprises the following steps of:under a room-temperature open system, adding a substrate 2-substituted-1, 3-oxo-thio-cyclopentane and a catalytic amount of a photosensitizer Eosin Y into a proper amount of acetonitrile; and performing irradiating with a blue LED lamp for 3 hours while stirring to obtain the corresponding aldehyde compound with favorable yield. The method has the advantages of mild operation conditions, greenness, environmental protection, no harsh water and oxygen removal operation and device, realization of the reaction at room temperature, high substrate conversion rate, simple and easy post-treatment, andprovides a good method for removing the 1, 2-mercaptoethanol acetal protecting group at present.
