1003-29-8Relevant articles and documents
Visible-light mediated facile dithiane deprotection under metal free conditions
Dharpure, Pankaj D.,Bhowmick, Anindita,Warghude, Prakash K.,Bhat, Ramakrishna G.
, (2020)
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.
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Kobayashi,T. et al.
, p. 3255 - 3258 (1975)
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Molybdenum complex with bulky chelates as a functional model for molybdenum oxidases
Leppin, Jana,F?rster, Christoph,Heinze, Katja
, p. 12416 - 12427 (2014)
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.
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Smith
, p. 3842,3844 (1954)
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Neutrophil-Selective Fluorescent Probe Development through Metabolism-Oriented Live-Cell Distinction
Gao, Min,Lee, Sun Hyeok,Park, Sang Hyuk,Ciaramicoli, Larissa Miasiro,Kwon, Haw-Young,Cho, Heewon,Jeong, Joseph,Chang, Young-Tae
, p. 23743 - 23749 (2021)
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.
Deprotection of N-sulfonyl nitrogen-heteroaromatics with tetrabutylammonium fluoride
Yasuhara, Akito,Sakamoto, Takao
, p. 595 - 596 (1998)
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.
Development of 5-(aminomethyl)pyrrole-2-carboxylic acid as a constrained surrogate of Gly-ΔAla and its application in peptidomimetic studies
Chakraborty, Tushar K,Krishna Mohan,Kiran Kumar,Kunwar, Ajit C
, p. 2589 - 2592 (2002)
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.
Synthesis of some diethylphosphono substituted 3H-pyrrolizines
Loussouarn,Servant,Guervenou,Sturtz
, p. 275 - 285 (1996)
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.
Application of flow chemistry to the reduction of nitriles to aldehydes
Mu?oz, Juan De M.,Alcázar, Jesús,De La Antonio, Hoz,Díaz-Ortiz, Angel
, p. 6058 - 6060 (2011)
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.
LITHIATION OF THE 6-DIMETHYLAMINO-1-AZAFULVENE DIMER. A VERSATILE SYNTHESIS OF 5-SUBSTITUTED PYRROLE-2-CARBOXALDEHYDES.
Muchowski, Joseph M.,Hess, Petr
, p. 777 - 780 (1988)
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.
In Situ vinylpyrrole synthesis. Diels-alder reactions with maleimides to give tetrahydroindoles
Noland, Wayland E.,Lanzatella, Nicholas P.,Sizova, Elena P.,Venkatraman, Lakshmanan,Afanasyev, Oleg V.
, p. 503 - 534 (2009)
(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.
Halogen–metal exchange on bromoheterocyclics with substituents containing an acidic proton via formation of a magnesium intermediate
Tian, Qingqiang,Shang, Suqin,Wang, Huajun,Shi, Guoqiang,Li, Zhiyao,Yuan, Jianyong
, (2017)
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.
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Cresp,Sargent
, p. 807 (1972)
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Transition-Metal-Free CO-Releasing BODIPY Derivatives Activatable by Visible to NIR Light as Promising Bioactive Molecules
Palao, Eduardo,Slanina, Tomá?,Muchová, Lucie,?olomek, Tomá?,Vítek, Libor,Klán, Petr
, p. 126 - 133 (2016)
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.
Facile and Scalable Methodology for the Pyrrolo[2,1-f][1,2,4]triazine of Remdesivir
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.
supporting information, p. 82 - 90 (2022/01/28)
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.
Investigating Alkylated Prodigiosenes and Their Cu(II)-Dependent Biological Activity: Interactions with DNA, Antimicrobial and Photoinduced Anticancer Activity
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.
supporting information, (2021/12/24)
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