- Visible-light mediated facile dithiane deprotection under metal free conditions
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Visible light mediated facile and selective dithiane deprotection under metal free conditions is developed. Eosin Y (1 mol%) proved to be an effective catalyst for the dithiane deprotection under the ambient photoredox conditions. The standard household compact fluorescent light source (CFL bulb) proved to be effective under open-air conditions in aqueous acetonitrile at room temperature. The protocol that exhibits a broad substrate scope and functional group tolerance has been shown to expand to a range of transformations for the electron-rich and -deficient thioacetals and thioketals. The synthetic utility of this protocol has also been demonstrated by gram-scale application.
- Dharpure, Pankaj D.,Bhowmick, Anindita,Warghude, Prakash K.,Bhat, Ramakrishna G.
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- Molybdenum complex with bulky chelates as a functional model for molybdenum oxidases
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The novel bulky Schiff base chelate ligand [(4,5-diisopropyl-1H-pyrrole-2-yl)methylene]-4-(tert-butyl)aniline (iPr2HL) bearing two isopropyl groups close to the pyrrole nitrogen atom reacts with MoCl2(dme)O2 (dme = 1,2-dimethoxyethane) to give the sterically congested complex MoVI(iPr2L)2O2 (iPr21; OC-6-4-4 configuration). In spite of the increased steric shielding of the [MoO2] unit iPr21 is active in oxygen-atom transfer to PMe3 and PPh3 to give OPMe3 and OPPh3, respectively. Because of the increased steric bulk of the chelate ligand, formation of dinuclear complexes [MoV(iPr2L)2O]2(μ-O) (iPr23) by comportionation is effectively prevented in contrast to the highly favored formation of [MoV(H2L)2O]2(μ-O) (H23) with the less bulky ligand H2HL. Instead, the smaller PMe3 ligand coordinates to the resulting pentacoordinate intermediate MoIV(iPr2L)2O (iPr25), giving the hexacoordinate complex MoIV(iPr2L)2O(PMe3) (iPr22) with OC-6-3-3 configuration. The larger potential ligands PPh3 and OPPh3 are only able to weakly coordinate to iPr25, giving labile and sensitive MoIV(iPr2L)2O(L) complexes (iPr26, L = PPh3; iPr27, L = OPPh3). Traces of water and dioxygen in solutions of iPr26/iPr27 yield the di(μ-oxido) complex [MoV(iPr2L)O]2(μ-O)2 (iPr24) with reduced steric congestion due to dissociation of the bulky chelate ligands. According to electron paramagnetic resonance studies, the much more strongly bound small PMe3 ligand in iPr22 can be slowly liberated by one-electron oxidation to MoV, with Ag+ leaving a free coordination site at MoV. Hence, essentially pentacoordinate MoIV and MoV complexes are accessible as a result of the increased steric bulk.
- Leppin, Jana,F?rster, Christoph,Heinze, Katja
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- Schiff bases containing triphenylamine and pyrrole units: Synthesis and electrochromic, acidochromic properties
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Five Schiff bases (SBs) containing pyrrole and different triphenylamine (TPA) moieties were synthesized and the structures were confirmed by infrared spectroscopy (IR) and the nuclear magnetic resonance (NMR) technique. SB1 exhibited intense fluorescence emission in contrast to SB2-SB5. The electrochemical behaviors of the SBs were investigated by the cyclic voltammetry (CV) technique. SB2-SB5 exhibited redox stability with one well-defined and reversible redox couple upon electrochemical oxidation. On the contrary, SB1 revealed two oxidation peaks and one reduction peak in the first CV curve, followed by four well-defined redox couples in the steady-state CV curves. Electrochromic behaviors of the SBs have been observed, accompanied with a new absorption peak appearing with obvious color change from pale yellow neutral form to red oxidation form. SB1-SB5 also displayed sensitive acidochromic behaviors, and a linear dependence of maximum absorption wavelength as a function of pH values has been observed which proved the SBs could be used as alternative pH sensors in the given range.
- Li, Yu,Zhang, Yanhong,Niu, Haijun,Wang, Cheng,Qin, Chuanli,Bai, Xuduo,Wang, Wen
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- Gold-catalyzed oxime-oxime rearrangement
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The gold-catalyzed reaction of pyrrole and indole oximes having a propargyl group attached to the nitrogen atom was studied. The selective 6-endo-dig mode of cyclization was observed for the terminal alkynes giving rise to the formation of pyrazine N-oxides in the presence of a gold catalyst. However, the reaction with substituted alkyne transferred the oxime functionality intramolecularly from one carbon atom to another via the 7-endo-dig cyclization process. This transformation is unprecedented in the literature and is named an oxime-oxime rearrangement.
- Guven, Sinem,Ozer, Merve Sinem,Kaya, Serdal,Menges, Nurettin,Balci, Metin
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- Neutrophil-Selective Fluorescent Probe Development through Metabolism-Oriented Live-Cell Distinction
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Human neutrophils are the most abundant leukocytes and have been considered as the first line of defence in the innate immune system. Selective imaging of live neutrophils will facilitate the in situ study of neutrophils in infection or inflammation events as well as clinical diagnosis. However, small-molecule-based probes for the discrimination of live neutrophils among different granulocytes in human blood have yet to be reported. Herein, we report the first fluorescent probe NeutropG for the specific distinction and imaging of active neutrophils. The selective staining mechanism of NeutropG is elucidated as metabolism-oriented live-cell distinction (MOLD) through lipid droplet biogenesis with the help of ACSL and DGAT. Finally, NeutropG is applied to accurately quantify neutrophil levels in fresh blood samples by showing a high correlation with the current clinical method.
- Gao, Min,Lee, Sun Hyeok,Park, Sang Hyuk,Ciaramicoli, Larissa Miasiro,Kwon, Haw-Young,Cho, Heewon,Jeong, Joseph,Chang, Young-Tae
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- Pincer ligands based on α-amino acids: I. Synthesis of polydentate ligands from pyrrole-2,5-dicarbaldehyde
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New chiral pincer ligands having CH=N moieties were synthesized by condensation of 1H-pyrrole-2,5-dicarbaldehyde with l-methionine and l-histidine methyl esters. Their reduction under mild conditions (NaBH4, -30°C) gave the corresponding amine ligands in high yields. An improved procedure for the preparation of 1H-pyrrole-2,5-dicarbaldehyde was proposed.
- Knizhnikov,Borisova,Yurashevich,Popova,Chernyad'ev,Zubreichuk,Reshetova
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- Deprotection of N-sulfonyl nitrogen-heteroaromatics with tetrabutylammonium fluoride
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The deprotection of N-methylsulfonyl, N-(p-toluenesufonyl), and N-phenylsulfonyl nitrogen-heteroaromatic compounds proceeds easily in excellent yields by refluxing with tetrabutylammonium fluoride (TBAF) in THF.
- Yasuhara, Akito,Sakamoto, Takao
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- Development of 5-(aminomethyl)pyrrole-2-carboxylic acid as a constrained surrogate of Gly-ΔAla and its application in peptidomimetic studies
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A new peptidomimetic scaffold based on 5-(aminomethyl)pyrrole-2-carboxylic acid (1) is developed for the first time and used as a conformationally constrained surrogate of the Gly-ΔAla dipeptide isostere (2) to prepare peptides 3 and 4.
- Chakraborty, Tushar K,Krishna Mohan,Kiran Kumar,Kunwar, Ajit C
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- Effect of aromatic π-bridges on molecular structures and optoelectronic properties of A-π-D-π-A small molecular acceptors based on indacenodithiophene
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Investigation on the relationship between molecular structure and device performance is of great important to develop highly efficient A-π-D-π-A small molecular acceptors (SMAs). However, there is still lack of a complete and in-depth study on effects of
- Chen, Yueju,Liang, Jingtang,Shen, Ping,Wang, Linqiao,Weng, Chao,Yu, Yufu
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- Synthesis of some diethylphosphono substituted 3H-pyrrolizines
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The preparation of various alkyl substituted monophosphonate 3H-pynolizines via a tandem Michael □ Horner-Emmons reaction is reported. These products were prepared from tetraethyl ethylidene gem-bisphosphonate and corresponding 2-acylpyrroles.
- Loussouarn,Servant,Guervenou,Sturtz
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- Molecularly Defined Manganese Catalyst for Low-Temperature Hydrogenation of Carbon Monoxide to Methanol
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Methanol synthesis from syngas (CO/H2 mixtures) is one of the largest manmade chemical processes with annual production reaching 100 million tons. The current industrial method proceeds at high temperatures (200-300 °C) and pressures (50-100 atm) using a copper-zinc-based heterogeneous catalyst. In contrast, here, we report a molecularly defined manganese catalyst that allows for low-temperature/low-pressure (120-150 °C, 50 bar) carbon monoxide hydrogenation to methanol. This new approach was evaluated and optimized by quantum mechanical simulations virtual high-throughput screenings. Crucial for this achievement is the use of amine-based promoters, which capture carbon monoxide to give formamide intermediates, which then undergo manganese-catalyzed hydrogenolysis, regenerating the promoter. Following this conceptually new approach, high selectivity toward methanol and catalyst turnover numbers (up to 3170) was achieved. The proposed general catalytic cycle for methanol synthesis is supported by model studies and detailed spectroscopic investigations.
- Ryabchuk, Pavel,Stier, Kenta,Junge, Kathrin,Checinski, Marek P.,Beller, Matthias
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- Application of flow chemistry to the reduction of nitriles to aldehydes
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Reduction of nitriles to aldehydes with diisobutylaluminium hydride (DIBAL-H) is an important transformation in organic chemistry. But the use of this reaction is limited for the lack of reproducibility due to the instability of the intermediates formed. In the current article we disclose the improvement of the reaction applying continuous flow technology.
- Mu?oz, Juan De M.,Alcázar, Jesús,De La Antonio, Hoz,Díaz-Ortiz, Angel
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- Mild deprotection of tert-butyl carbamates of NH-heteroarenes under basic conditions
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Aqueous methanolic potassium carbonate under reflux has been demonstrated to be a highly effective deprotective agent for the tert -butyl carbamates of indoles, indazoles, carbazole, thiazoloindole, and pyrrole. The method is a mild one and is particularly expeditious for NH-heteroarenes bearing electron-withdrawing groups. Copyright Taylor & Francis Group, LLC.
- Chakrabarty, Manas,Kundu, Taraknath,Harigaya, Yoshihiro
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- LITHIATION OF THE 6-DIMETHYLAMINO-1-AZAFULVENE DIMER. A VERSATILE SYNTHESIS OF 5-SUBSTITUTED PYRROLE-2-CARBOXALDEHYDES.
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Metalation of the dimer 1 of 6-dimethylamino-1-azafulvene, with t-butyllithium at -15 deg C, gave the 3,8-dilithio derivate 2, which after reaction with diverse electrophilic reagents and hydrolysis, provided a wide variety of 5-substituted pyrrole-2-carboxaldehydes 5.
- Muchowski, Joseph M.,Hess, Petr
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- Characterization of Carboxylic Acid Reductases as Enzymes in the Toolbox for Synthetic Chemistry
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Carboxylic acid reductase enzymes (CARs) meet the demand in synthetic chemistry for a green and regiospecific route to aldehydes from their respective carboxylic acids. However, relatively few of these enzymes have been characterized. A sequence alignment with members of the ANL (Acyl-CoA synthetase/ NRPS adenylation domain/Luciferase) superfamily of enzymes shed light on CAR functional dynamics. Four unstudied enzymes were selected by using a phylogenetic analysis of known and hypothetical CARs, and for the first time, a thorough biochemical characterization was performed. Kinetic analysis of these enzymes with various substrates shows that they have a broad but similar substrate specificity. Electron-rich acids are favored, which suggests that the first step in the proposed reaction mechanism, attack by the carboxylate on the α-phosphate of adenosine triphosphate (ATP), is the step that determines the substrate specificity and reaction kinetics. The effects of pH and temperature provide a clear operational window for the use of these CARs, whereas an investigation of product inhibition by NADP+, adenosine monophosphate, and pyrophosphate indicates that the binding of substrates at the adenylation domain is ordered with ATP binding first. This study consolidates CARs as important and exciting enzymes in the toolbox for sustainable chemistry and provides specifications for their use as a biocatalyst.
- Finnigan, William,Thomas, Adam,Cromar, Holly,Gough, Ben,Snajdrova, Radka,Adams, Joseph P.,Littlechild, Jennifer A.,Harmer, Nicholas J.
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- In Situ vinylpyrrole synthesis. Diels-alder reactions with maleimides to give tetrahydroindoles
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(Chemical Equation Presented) A series of 108 tetrahydroindoles has been prepared by a one-pot synthesis from 2-alkylpyrroles, cyclic ketones, maleimides, and an acid catalyst. A 5-vinylpyrrole is formed by an acid-catalyzed condensation of a 2-alkyl-substituted pyrrole with a ketone, which is subsequently trapped in situ by a maleimide in a predominantly endo-addition Diels-Alder reaction. Isomerization of the double bond into the pyrrole ring gives a tetrahydroindole with predominant cis-fusion of the cycloalkane ring.
- Noland, Wayland E.,Lanzatella, Nicholas P.,Sizova, Elena P.,Venkatraman, Lakshmanan,Afanasyev, Oleg V.
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- A New Procedure for Formylation of Less Active Aromatics
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The formylation of aromatic compounds with trifluoromethanesulphonic anhydride/dimethylformamide complex 2 takes place easily as compared to the normal Vilsmeier-Haack reaction.
- Martinez, Antonio Garcia,Alvarez, Roberto Martinez,Barcina, Jose Osio,Cerero, S. Moya de la,Vilar, E. Teso,et al.
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- Halogen–metal exchange on bromoheterocyclics with substituents containing an acidic proton via formation of a magnesium intermediate
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A selective and practical bromine–metal exchange on bromoheterocyclics bearing substituents with an acidic proton under non-cryogenic conditions was developed by a simple modification of an existing protocol. Our protocol of using a combination of i-PrMgCl and n-BuLi has not only solved the problem of intermolecular quenching that often occurred when using alkyl lithium alone as the reagent for halogen–lithium exchange, but also offered a highly selective method for performing bromo–metal exchange on dibrominated arene compounds through chelation effect.
- Tian, Qingqiang,Shang, Suqin,Wang, Huajun,Shi, Guoqiang,Li, Zhiyao,Yuan, Jianyong
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- Probing the hydrolytic reactivity of 2-difluoromethyl pyrroles
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α-Difluoromethyl pyrroles were found to be stable while N-protected with an electron-withdrawing group. Due to the propensity of pyrroles to access azafulvenium-like intermediates, the C-F bonds of an α-difluoromethyl substituent are labile under hydrolytic conditions. The presence of certain electron-withdrawing substituents about the pyrrolic ring can accelerate this process, as determined through a kinetic comparison of the deprotection and subsequent hydrolysis reactions of N-protected β-aryl α-difluoromethyl pyrroles.
- Melanson, Jennifer A.,Figliola, Carlotta,Smithen, Deborah A.,Kajetanowicz, Aleksandra K.,Thompson, Alison
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- Selective and Efficient Formylation of Indoles (C3) and Pyrroles (C2) Using 2,4,6-Trichloro-1,3,5-Triazine/Dimethylformamide (TCT/DMF) Mixed Reagent
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This study introduces an efficient method for the selective formylation of indoles and pyrroles at the positions of C(3) and C(2), respectively. The mixture of three equivalents of N,N-dimethylformamide and one equivalent of 2,4,6-trichloro-1,3,5-triazine (cyanuric chloride) generates an easy handling formylating agent for the efficient formylation of these classes of compounds to give the corresponding aldehydes under mild reaction conditions. This procedure was highly efficient, and a range of formylated indoles and pyrroles were obtained in good to excellent yields.
- Iranpoor, Nasser,Panahi, Farhad,Erfan, Soodabeh,Roozbin, Fatemeh
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- Transition-Metal-Free CO-Releasing BODIPY Derivatives Activatable by Visible to NIR Light as Promising Bioactive Molecules
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Carbon monoxide-releasing molecules (CORMs) are chemical agents used to administer CO as an endogenous, biologically active molecule. A precise spatial and temporal control over the CO release is the major requirement for their applications. Here, we report the synthesis and properties of a new generation of transition-metal-free carbon monoxide-releasing molecules based on BODIPY chromophores (COR-BDPs) activatable by visible-to-NIR (up to 730 nm) light. We demonstrate their performance for both in vitro and in vivo experimental settings, and we propose the mechanism of the CO release based on steady-state and transient spectroscopy experiments and quantum chemical calculations.
- Palao, Eduardo,Slanina, Tomá?,Muchová, Lucie,?olomek, Tomá?,Vítek, Libor,Klán, Petr
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- Highly atom efficient synthesis of 2,2,4,5-tetrasubstituted 3(2H)-furanones having both hydroxyl and amino substituents
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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.
- Antony, Jesna,Mathai, Sindhu,Natarajan, Rakesh,P. Musthafa, Sumi,Rappai, John P.,S. Devaky, Karakkattu
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supporting information
(2022/02/25)
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- Facile and Scalable Methodology for the Pyrrolo[2,1-f][1,2,4]triazine of Remdesivir
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Pyrrolo[2,1-f][1,2,4]triazine (1) is an important regulatory starting material in the production of the antiviral drug remdesivir. Compound 1 was produced through a newly developed synthetic methodology utilizing simple building blocks such as pyrrole, chloramine, and formamidine acetate by examining the mechanistic pathway for the process optimization exercise. Triazine 1 was obtained in 55% overall yield in a two-vessel-operated process. This work describes the safety of the process, impurity profiles and control, and efforts toward the scale-up of triazine for the preparation of kilogram quantity.
- Roy, Sarabindu,Yadaw, Ajay,Roy, Subho,Sirasani, Gopal,Gangu, Aravind,Brown, Jack D.,Armstrong, Joseph D.,Stringham, Rodger W.,Gupton, B. Frank,Senanayake, Chris H.,Snead, David R.
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supporting information
p. 82 - 90
(2022/01/28)
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- Synthesis process of retegravir intermediate
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The invention relates to a synthesis process of a retegravir intermediate 7-iodine-4-amido pyrrolo [2,1-F] [1, 2, 4] triazine. The method comprises the following steps: by using pyrrole as an initialraw material, carrying out aldehyde groupintroduction through phosphorus oxychloride-DMF to obtain 2-aldehyde group pyrrole; preparing a 2-cyano key intermediate through ammonium sulfate, wherein thesteps is the key step of the process; cyclizing the cyano intermediate and formamidine acetate to prepare a 4-amino intermediate; reacting with NIS and adding iodine to prepare the target compound 7-iodine-4-amido pyrrolo [2,1-F] [1, 2, 4] triazine. The whole process has the advantages of simple and easily available raw materials, simple and easy operation, and very high economic value and socialbenefit.
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Paragraph 0005; 0020; 0021
(2021/03/11)
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- Investigating Alkylated Prodigiosenes and Their Cu(II)-Dependent Biological Activity: Interactions with DNA, Antimicrobial and Photoinduced Anticancer Activity
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Prodigiosenes are a family of red pigments with versatile biological activity. Their tripyrrolic core structure has been modified many times in order to manipulate the spectrum of activity. We have been looking systematically at prodigiosenes substituted
- Colard-Thomas, Julien,Danz, Karin,Doniz Kettenmann, Sebastian,Kraft, Matilda,Kulak, Nora,Schwarz, Stefan,Wagner, Sylvia,White, Matthew,Wiehe, Arno,Wieland, Gerhard,Fe?ler, Andrea T.
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supporting information
(2021/12/24)
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- Visible-Light-Driven Oxidative Cleavage of Alkenes Using Water-Soluble CdSe Quantum Dots
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The oxidative cleavage of C=C bonds is an important chemical reaction, which is a popular reaction in the photocatalytic field. However, high catalyst-loading and low turnover number (TON) are general shortcomings in reported visible-light-driven reactions. Herein, the direct oxidative cleavage of C=C bonds through water-soluble CdSe quantum dots (QDs) is described under visible-light irradiation at room temperature with high TON (up to 3.7×104). Under the same conditions, water-soluble CdSe QDs could also oxidize sulfides to sulfoxides with 51–84 % yields and TONs up to 3.4×104. The key features of this photocatalytic protocol include high TONs, wide substrates scope, low catalyst loadings, simple and mild reaction conditions, and molecular O2 as the oxidant.
- Li, Jianing,Zhao, Jingnan,Ma, Cunfei,Yu, Zongyi,Zhu, Hongfei,Yun, Lei,Meng, Qingwei
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p. 4985 - 4992
(2021/10/16)
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- Photo-on-Demand Synthesis of Vilsmeier Reagents with Chloroform and Their Applications to One-Pot Organic Syntheses
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The Vilsmeier reagent (VR), first reported a century ago, is a versatile reagent in a variety of organic reactions. It is used extensively in formylation reactions. However, the synthesis of VR generally requires highly toxic and corrosive reagents such as POCl3, SOCl2, or COCl2. In this study, we found that VR is readily obtained from a CHCl3 solution containing N,N-dimethylformamide or N,N-dimethylacetamide upon photo-irradiation under O2 bubbling. The corresponding Vilsmeier reagents were obtained in high yields with the generation of gaseous HCl and CO2 as byproducts to allow their isolations as crystalline solid products amenable to analysis by X-ray crystallography. With the advantage of using CHCl3, which bifunctionally serves as a reactant and a solvent, this photo-on-demand VR synthesis is available for one-pot syntheses of aldehydes, acid chlorides, formates, ketones, esters, and amides.
- Liang, Fengying,Eda, Kazuo,Okazoe, Takashi,Wada, Akihiro,Mori, Nobuaki,Konishi, Katsuhiko,Tsuda, Akihiko
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p. 6504 - 6517
(2021/05/06)
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- Synthesis and bioevaluation and doking study of 1H-pyrrolo[2,3-b]pyridine derivatives bearing aromatic hydrazone moiety as c-Met inhibitors
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Two series of aromatic hydrazone derivatives bearing 1H-pyrrolo[2,3-b]pyridine moiety (7a–r, 8a–i, 12a–b, 13a–c, 16a–d and 17a–e) were designed, synthesized and evaluated for the IC50 values against four cancer cell lines (A549, HepG2, MCF-7and PC-3). Two selected compounds (7c and 17e) were further evaluated for the activity against c-Met, Flt-3, VEGFR-2 and EGFR kinases. The data indicated that targets compounds were selective for c-Met kinase. And the most promising compound 7c was further studied in terms of dose-dependent, time-dependent and cell apoptosis. Most of the compounds showed excellent cytotoxicity activity, especially the most promising compound 7c with the IC50 values of 0.82 ± 0.08 μM, 1.00 ± 0.11 μM, 0.93 ± 0.28 μM and 0.92 ± 0.17 μM against A549, HepG2, MCF-7 and PC-3 cell lines and 0.506 μM against c-Met kinase. Structure–activity relationships (SARs) and docking studies indicated that the activities of the phenyl hydrazone derivatives (7a–r and 8a–i) were superior to that of the heterocyclic hydrazone series (12a–b, 13a–c, 16a–d and 17a–e). What's more, the further studies indicated that the target compounds can induce apoptosis of A549 cells and arrest efficiently the cell cycle progression in G2/M phase of A549 cells.
- Wang, Wenhui,Xu, Shan,Duan, Yongli,Liu, Xiaobo,Li, Xiaojing,Wang, Caolin,Zhao, Bingbing,Zheng, Pengwu,Zhu, Wufu
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p. 315 - 327
(2018/01/17)
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- Reduction of N,N-Dimethylcarboxamides to Aldehydes by Sodium Hydride–Iodide Composite
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A new and concise protocol for selective reduction of N,N-dimethylamides into aldehydes was established using sodium hydride (NaH) in the presence of sodium iodide (NaI) under mild reaction conditions. The present protocol with the NaH-NaI composite allows for reduction of not only aromatic and heteroaromatic but also aliphatic N,N-dimethylamides with wide substituent compatibility. Retention of α-chirality in the reduction of α-enantioriched amides was accomplished. Use of sodium deuteride (NaD) offers a new step-economical alternative to prepare deuterated aldehydes with high deuterium incorporation rate. The NaH-NaI composite exhibits unique chemoselectivity for reduction of N,N-dimethylamides over ketones.
- Chan, Guo Hao,Ong, Derek Yiren,Yen, Zhihao,Chiba, Shunsuke
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- NOVEL FUSED PYRIMIDINONE AND TRIAZINONE DERIVATIVES, THEIR PROCESS OF PREPARATION AND THEIR THERAPEUTIC USES AS ANTIFUNGAL AND/OR ANTIPARASITIC AGENTS
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The present invention concerns novel fused pyrimidinone and triazinone derivatives of formula (I), their process of preparation and their use as antifungal or antiparasitic agents.
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(2017/02/28)
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- C=N Bond Activation and Hydration by an Iron(III) Complex with Asymmetric Sulfur Oxygenation
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The presence of asymmetric cysteine sulfur-oxygenation donors, consisting of sulfenate (SO), sulfinate (SO2), and thiolate (S), around a trivalent iron is essential for the catalytic function of Fe- or Co-type nitrile hydratase (NHase). To gain
- Wu, Yun-Ru,Chang, Chia-Ming,Wang, Chia-Chi,Hsieh, Chang-Chih,Horng, Yih-Chern
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supporting information
p. 840 - 843
(2017/02/15)
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- Isothiourea-catalysed enantioselective pyrrolizine synthesis: Synthetic and computational studies
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The catalytic enantioselective synthesis of a range of cis-pyrrolizine carboxylate derivatives with outstanding stereocontrol (14 examples, >95:5 dr, >98:2 er) through an isothiourea-catalyzed intramolecular Michael addition-lactonisation and ring-opening
- Stark, Daniel G.,Williamson, Patrick,Gayner, Emma R.,Musolino, Stefania F.,Kerr, Ryan W. F.,Taylor, James E.,Slawin, Alexandra M. Z.,O'Riordan, Timothy J. C.,Macgregor, Stuart A.,Smith, Andrew D.
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supporting information
p. 8957 - 8965
(2016/10/07)
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- Dipyrrolonaphthyridinediones - Structurally unique cross-conjugated dyes
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Red-emissive dyes based on a previously unknown skeleton - dipyrrolo[1,2-b:1′,2′-g][2,6]naphthyridine-5,11-dione - can be easily synthesized from simple and inexpensive reagents by one- or two-step routes. A careful selection of the substituents gives access to a variety of dipyrrolonaphthyridinedione derivatives with intense fluorescence in the range of 520-740 nm.
- Grzybowski, Marek,Deperasińska, Irena,Chotkowski, Maciej,Banasiewicz, Marzena,Makarewicz, Artur,Kozankiewicz, Boles?aw,Gryko, Daniel T.
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supporting information
p. 5108 - 5111
(2016/04/26)
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- Structure-activity relationship of pyrrolyl diketo acid derivatives as dual inhibitors of HIV-1 integrase and reverse transcriptase ribonuclease H domain
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The development of HIV-1 dual inhibitors is a highly innovative approach aimed at reducing drug toxic side effects as well as therapeutic costs. HIV-1 integrase (IN) and reverse transcriptase-associated ribonuclease H (RNase H) are both selective targets
- Cuzzucoli Crucitti, Giuliana,Métifiot, Mathieu,Pescatori, Luca,Messore, Antonella,Madia, Valentina Noemi,Pupo, Giovanni,Saccoliti, Francesco,Scipione, Luigi,Tortorella, Silvano,Esposito, Francesca,Corona, Angela,Cadeddu, Marta,Marchand, Christophe,Pommier, Yves,Tramontano, Enzo,Costi, Roberta,Di Santo, Roberto
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p. 1915 - 1928
(2015/04/27)
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- Organocatalytic enantioselective multicomponent synthesis of pyrrolopiperazines
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The first organocatalytic multicomponent synthesis of enantioenriched pyrrolopiperazines is reported. These biologically relevant fused tricyclic products were obtained under catalytic iminium activation through a reaction sequence involving an enantioselective Michael addition followed by an iminium ion trapping via Pictet-Spengler cyclization (MAPS sequence). Substantial possibilities for variation on the three reaction partners [β-keto ester, enal and N-(2-aminoethyl)pyrrole] along with excellent enantioselectivities are the highlights of the present transformation.
- Du, Haiying,Rodriguez, Jean,Bugaut, Xavier,Constantieux, Thierry
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supporting information
p. 851 - 856
(2014/04/03)
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- Extending the stetter reaction with 1,6-acceptors
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Pace Stetter: A new N-heterocyclic carbene (NHC)-catalysed transformation is described-the intramolecular vinylogous Stetter reaction. This transformation can be effected with both thiazolium and triazolium-based catalysts, using aromatic and aliphatic aldehydes, employing α,β,γ,δ- unsaturated esters, ketones, phosphonates and N-acylpyrroles, and can be conducted enantioselectively (see scheme). Copyright
- Law, Katherine R.,McErlean, Christopher S. P.
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supporting information
p. 15852 - 15855
(2014/04/03)
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- Design and synthesis of pyrrolotriazepine derivatives: An experimental and computational study
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The pyrrole derivatives having carbonyl groups at the C-2 position were converted to N-propargyl pyrroles. The reaction of those compounds with hydrazine monohydrate resulted in the formation of 5H-pyrrolo[2,1-d][1,2,5] triazepine derivatives. The synthesis of these compounds was accomplished in three steps starting from pyrrole. On the other hand, attempted cyclization of a pyrrole ester substituted with a propargyl group at the nitrogen atom gave, unexpectedly, the six-membered cyclization product, 2-amino-3-methylpyrrolo[1,2- a]pyrazin-1(2H)-one as the major product. The expected cyclization product with a seven-membered ring, 4-methyl-2,3-dihydro-1H-pyrrolo[2,1-d][1,2,5]triazepin-1- one was formed as the minor product and was converted quantitatively to the major product. The formation mechanism of the products was investigated, and the results obtained were also supported by theoretical calculations.
- Menges, Nurettin,Sari, Ozlem,Abdullayev, Yusif,Erdem, Safiye Sag,Balci, Metin
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p. 5184 - 5195
(2013/07/25)
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- Synthesis and evaluation of novel marine bromopyrrole alkaloid-based hybrids as anticancer agents
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A series of twenty three novel hybrids of marine bromopyrrole alkaloids with chalcone, isoxazole and flavone structural features were synthesized and evaluated for in vitro anticancer activity by MTT assay against five human cancer cell lines. Among the synthesized chalcones, hybrids 4a and 4h (IC50 range: 0.18 μM-12.00 μM) showed anticancer activity against all the tested cancer cell lines. Promising cytotoxic activities were exhibited by flavones derivatives, 5a and 5b (0.41 μM-1.28 μM) against cell lines PA1 and KB403. Isoxazole hybrids, 6b-6e selectively inhibited oral and mouth cancer cell line KB403, among which 6c (IC50 = 2.45 μM) was found to be most active.
- Rane, Rajesh A.,Sahu, Niteshkumar U.,Gutte, Shweta D.,Mahajan, Anand A.,Shah, Chetan P.,Bangalore, Pavankumar
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p. 793 - 799
(2013/07/25)
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- New nucleotide-competitive non-nucleoside inhibitors of terminal deoxynucleotidyl transferase: Discovery, characterization, and crystal structure in complex with the target
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Terminal deoxynucletidyl transferase (TdT) is overexpressed in some cancer types, where it might compete with pol μ during the mutagenic repair of double strand breaks (DSBs) through the nonhomologous end joining (NHEJ) pathway. Here we report the discove
- Costi, Roberta,Cuzzucoli Crucitti, Giuliana,Pescatori, Luca,Messore, Antonella,Scipione, Luigi,Tortorella, Silvano,Amoroso, Alessandra,Crespan, Emmanuele,Campiglia, Pietro,Maresca, Bruno,Porta, Amalia,Granata, Ilaria,Novellino, Ettore,Gouge, Jéro?me,Delarue, Marc,Maga, Giovanni,Di Santo, Roberto
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supporting information
p. 7431 - 7441
(2013/10/21)
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- Continuous flow production of thermally unstable intermediates in a microreactor with inline IR-analysis: Controlled Vilsmeier-Haack formylation of electron-rich arenes
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The Vilsmeier-Haack formylation of aromatic compounds is a well-established process in organic synthesis, largely driven by the fact that the resulting aldehydes are generally useful intermediates for the synthesis of fine chemicals and pharmaceutical products. Industrial-scale production, however, is often hampered by laborious procedures requiring the use of hazardous chemicals to produce the highly reactive intermediates. In order to circumvent these issues, a flow chemistry approach was developed. This article describes the design and semiautomated optimization of the Vilsmeier-Haack formylation in continuous flow and subsequent scale-up to preparative volumes in an intrinsically safe manner.
- Van Den Broek, Sebastiaan A. M. W.,Leliveld, Jeroen R.,Becker, Rene,Delville, Marielle M. E.,Nieuwland, Pieter J.,Koch, Kaspar,Rutjes, Floris P. J. T.
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scheme or table
p. 934 - 938
(2012/08/27)
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- Design, synthesis and antifungal activities of novel pyrrole alkaloid analogs
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A series of novel analogs of pyrrole alkaloid were designed and synthesized by a facile method and their structures were characterized by 1H NMR, 13C NMR and high-resolution mass spectrometry (HRMS). The structure of compound 2a was identified by 2D NMR including heteronuclear multiple-quantum coherence (HMQC), heteronuclear multiple-bond correlation (HMBC) and H-H correlation spectrometry (H-H COSY) spectra. Their antifungal activities against five fungi were evaluated, and the results indicated that some of the title compounds showed moderate fungicidal activities in vitro against Alternaria solani, Cercospora arachidicola, Fusarium omysporum, Gibberella zeae and Physalospora piricola at the dosage of 50 μg mL -1. Compound 2a and 3a exhibited good activities against P. piricola at low dosage.
- Wang, Ming-Zhong,Xu, Han,Liu, Tuan-Wei,Feng, Qi,Yu, Shu-Jing,Wang, Su-Hua,Li, Zheng-Ming
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scheme or table
p. 1463 - 1472
(2011/05/04)
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- Direct synthesis of chiral 1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazines via a catalytic asymmetric intramolecular aza-Friedel-Crafts reaction
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The direct asymmetric intramolecular aza-Friedel-Crafts reaction of N-aminoethylpyrroles with aldehydes catalyzed by a chiral phosphoric acid represents the first efficient method for the preparation of medicinally interesting chiral 1,2,3,4-tetrahydropyrrolo[1,2-a]pyrazines with high yields and high enantioselectivities. This strategy has been shown to be quite general toward various aldehydes and pyrrole derivatives.
- He, Yuwei,Lin, Maohui,Li, Zhongmin,Liang, Xinting,Li, Guilong,Antilla, Jon C.
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supporting information; scheme or table
p. 4490 - 4493
(2011/10/09)
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- Enantioselective addition of diethylzinc to aldehydes catalyzed by β-amino alcohols derived from (1R,2S)-norephedrine
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β-Amino alcohols derived from (1R,2S)-norephedrine were synthesized and used as ligands in the catalytic enantioselective diethylzinc addition to benzaldehydes. N-alkylated (1R,2S)-norephedrine-based derivative 3a gave the highest enantioselectivity. The effects of different parameters on the enantioselectivity of the product were investigated. Copyright
- Tasgin, Dilek Isik,Unaleroglu, Canan
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scheme or table
p. 33 - 37
(2010/10/01)
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- Access to indoles via Diels-Alder reactions of 2-vinylpyrroles with maleimides
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(Chemical Equation Presented) Variously substituted 2-vinylpyrroles underwent an endo-addition [4+2] cycloaddition reaction with maleimides followed by a spontaneous highly diastereoselective (93-98% de) isomerization to give tetrahydroindoles in moderate to excellent yield. Treatment with activated MnO2 in refluxing toluene provided the corresponding indoles in moderate to good yield. This highly convergent methodology for formation of indoles is versatile and the starting materials are conveniently prepared.
- Noland, Wayland E.,Lanzatella, Nicholas P.,Venkatraman, Lakshmanan,Anderson, Nicholas F.,Gullickson, Glen C.
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scheme or table
p. 1154 - 1176
(2010/03/04)
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- Synthesis of 1-vinylpyrrole-2-carbonitriles
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A new highly synthetically potent series of bifunctional pyrroles, 1-vinylpyrrole-2-carbonitriles, were synthesized from readily available 1-vinylpyrrole-2-carbaldehyde oximes by two methods: (1) reaction with acetylene (KOH/DMSO, 70 °C, 10 min, yields 58
- Trofimov, Boris A.,Vasil'tsov, Alexander M.,Mikhaleva, Al'bina I.,Ivanov, Andrey V.,Skital'tseva, Elena V.,Schmidt, Elena Yu.,Senotrusova, Elena Yu.,Ushakov, Igor A.,Petrushenko, Konstantin B.
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body text
p. 97 - 100
(2009/04/14)
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- Deprotection of N-BOC compounds
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Organic compounds having nitrogen atoms protected with t-butoxycarbonyl are effectively deprotected by heating in a fluorinated alcohol solution.
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Page/Page column 2
(2009/08/18)
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- Deprotection of N-BOC compounds
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Organic compounds having nitrogen atoms protected with t-butoxycarbonyl are effectively deprotected by heating in a fluorinated alcohol solution.
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Page/Page column 3
(2009/07/10)
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- Novel practical deprotection of N-Boc compounds using fluorinated alcohols
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The thermolytic deprotection of N-Boc compounds was accomplished using TFE (2,2,2-trifluoroethanol) or HFIP (hexafluoroisopropanol) as solvents. Even though the cleavage of the t-butylcarbamate (Boc) group can be achieved at solvent reflux temperature, the deprotection process was significantly accelerated under microwave-assisted conditions. The practicality of this methodology was demonstrated on alkyl, aryl, and heteroaromatic N-Boc-amines. Copyright Taylor & Francis Group, LLC.
- Choy, Jason,Jaime-Figueroa, Saul,Jiang, Laurence,Wagner, Paul
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p. 3840 - 3853
(2008/12/23)
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- Tungstate sulfuric acid (TSA)/ KMnO4 as a novel heterogeneous system for rapid deoximation
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Neat chlorosulfonic acid reacts with anhydrous sodium tungstate to give tungstate sulfuric acid (TSA), a new dibasic inorganic solid acid in which two sulfuric acid molecules connect to a tungstate moiety via a covalent bond. A variety of oximes were oxidized to their parent carbonyl compounds under mild conditions with excellent yields in short times by a heterogeneous wet TSA/KMnO4 in dichloromethane system.
- Karami, Bahador,Montazerozohori, Morteza
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p. 720 - 725
(2007/10/03)
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- Discovery of the pyrrolo[2,1-f][1,2,4]triazine nucleus as a new kinase inhibitor template
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The pyrrolo[2,1-f][1,2,4]triazine nucleus was identified as a novel kinase inhibitor template which effectively mimics the well-known quinazoline kinase inhibitor scaffold. Attachment of a 4-((3-chloro-4-fluorophenyl)amino) substituent to the template provided potent biochemical inhibitors of the tyrosine kinase activity of EGFR, as well as inhibition of cellular proliferation of the human colon tumor cell line DiFi. Attachment of a 4-((3-hydroxy-4-methylphenyl)amino) substituent provided potent inhibitors of VEGFR-2 which also showed effects on the VEGF-dependent proliferation of human umbilical vein endothelial cells. Biological activity was maintained with substitution at positions 5 or 6, but not 7, suggesting that the former positions are promising sites for introducing side chains which modulate physicochemical. properties. Preliminary inhibition studies with varying ATP concentrations suggest that, like the quinazoline-based kinase inhibitors, the pyrrolotriazine-based inhibitors bind in the ATP pocket.
- Hunt, John T.,Mitt, Toomas,Borzilleri, Robert,Gullo-Brown, Johnni,Fargnoli, Joseph,Fink, Brian,Han, Wen-Ching,Mortillo, Steven,Vite, Gregory,Wautlet, Barri,Wong, Tai,Yu, Chiang,Zheng, Xiaoping,Bhide, Rajeev
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p. 4054 - 4059
(2007/10/03)
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- 3-(4-Aroyl-1-methyl-1H-2-pyrrolyl)-N-hydroxy-2-alkylamides as a new class of synthetic histone deacetylase inhibitors. 1. Design, synthesis, biological evaluation, and binding mode studies performed through three different docking procedures
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Recently we reported a novel series of hydroxamates, called 3-(4-aroyl-1H-2-pyrrolyl)-N-hydroxy-2-propenamides (APHAs), acting as HDAC inhibitors (Massa, S.; et al. J. Med. Chem. 2001, 44, 2069-2072). Among them, 3-(4-benzoyl-1-methyl-1H-2-pyrrolyl)-N-hydroxy-2-propenamide 1 was chosen as lead compound, and its binding mode into the modeled HDAC1 catalytic core together with its histone hyperacetylation, antiproliferative, and cytodifferentiating properties in cell-based assays were investigated (Mai, A.; et al. J. Med. Chem. 2002, 45, 1778-1784). Here we report the results of some chemical manipulations performed on (i) the aroyl portion at the C4-pyrrole position, (ii) the N1-pyrrole substituent, and (iii) the hydroxamate moiety of 1 to determine structure-activity relationships and to improve enzyme inhibitory activity of APHAs. In the 1 structure, pyrrole N1-substitution with groups larger than methyl gave a reduction in HDAC inhibiting activity, and replacement of hydroxamate function with various non-hydroxamate, metal ion-complexing groups yielded poorly active or totally inactive compounds. On the contrary, proper substitution at the C4-position favorably affected enzyme inhibiting potency, leading to 8 (IC50 = 0.1 μM) and 9 (IC50 = 1.0 μM) which were 38- and 3.8-fold more potent than 1 in in vitro anti-HD2 assay. Against mouse HDAC1, 8 showed an IC50 = 0.5 μM (IC50 of 1 = 4.9 μM), and also in cell-based assay, 8 was endowed with higher histone hyperacetylating activity than 1, although it was less potent than TSA and SAHA. Such enhancement of inhibitory activity can be explained by the higher flexibility of the pyrrole C4-substituent of 8 which accounts for a considerably better fitting into the HDAC1 pocket and a more favorable enthalpy ligand receptor energy compared to 1. The enhanced fit allows a closer positioning of 8 hydroxamate moiety to the zinc ion. These findings were supported by extensive docking studies (SAD, DOCK, and Autodock) performed on both APHAs and reference drugs (TSA and SAHA).
- Mai, Antonello,Massa, Silvio,Ragno, Rino,Cerbara, Ilaria,Jesacher, Florian,Loidl, Peter,Brosch, Gerald
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p. 512 - 524
(2007/10/03)
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- Diethoxymethyl protected pyrroles: Synthesis and regioselective transformations
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Treatment of the acceptor-substituted pyrroles 1a-k with neat triethyl orthoformate gives access to the diethoxymethyl (DEM) protected derivatives 2a-k in high yield. Convenient and mild cleavage was achieved by subsequent treatment of the DEM-pyrroles 2a-k with trifluoroacetic acid in acetonitrile and aqueous NaOH at room temperature. DEM protection proved suitable for a variety of regioselective transformations involving directed orthometalation and iodine-magnesium exchange processes. Furthermore, electrophilic halogenations and Pd-catalyzed coupling reactions were also carried out.
- Bergauer,Gmeiner
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p. 2281 - 2288
(2007/10/03)
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- Isoquinoline compound melanocortin receptor ligands and methods of using same
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The invention relates to melanocortin receptor ligands and methods of using the ligands to alter or regulate the activity of a melanocortin receptor. The invention further relates to tetrahydroisoquinoline aromatic amines that function as melanocortin receptor ligands and as agents for controlling cytokine-regulated physiologic processes and pathologies, and combinatorial libraries thereof.
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