Structural assignment of a C10H12O3 ester by mass spectroscopy. An undergraduate organic problem

1976 ◽  
Vol 53 (6) ◽  
pp. 390 ◽  
Author(s):  
Alan P. Marchand ◽  
Danny Jackson
Keyword(s):  
Mass Spectroscopy ◽  
Structural Assignment

Photochemical and Electrochemical Reduction of Carbon Dioxide Catalyzed by a Polyoxometalate-Organic Photosensitizer Complex

2018 ◽  
Author(s):  
Chandan Dey ◽  
Ronny Neumann
Keyword(s):  
Carbon Dioxide ◽  
Cyclic Voltammetry ◽  
Formic Acid ◽  
Electrochemical Reduction ◽  
Mass Spectroscopy ◽  
Photochemical Reactions ◽  
Reducing Agent ◽  
Covalent Attachment ◽  
Hybrid Complex ◽  
Open Face

<p>A manganese substituted Anderson type polyoxometalate, [MnMo<sub>6</sub>O<sub>24</sub>]<sup>9-</sup>, tethered with an anthracene photosensitizer was prepared and used as catalyst for CO<sub>2</sub> reduction. The polyoxometalate-photosensitizer hybrid complex, obtained by covalent attachment of the sensitizer to only one face of the planar polyoxometalate, was characterized by NMR, IR and mass spectroscopy. Cyclic voltammetry measurements show a catalytic response for the reduction of carbon dioxide, thereby suggesting catalysis at the manganese site on the open face of the polyoxometalate. Controlled potentiometric electrolysis showed the reduction of CO<sub>2</sub> to CO with a TOF of ~15 sec<sup>-1</sup>. Further photochemical reactions showed that the polyoxometalate-anthracene hybrid complex was active for the reduction of CO<sub>2</sub> to yield formic acid and/or CO in varying amounts dependent on the reducing agent used. Control experiments showed that the attachment of the photosensitizer to [MnMo<sub>6</sub>O<sub>24</sub>]<sup>9-</sup> is necessary for photocatalysis.</p><div><br></div>

Synthesis and Reactivity of Precolibactin 886

2019 ◽  
Author(s):  
Seth Herzon ◽  
Alan R. Healy ◽  
kevin wernke ◽  
Chung Sub Kim ◽  
Nicholas Lees ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Gene Cluster ◽  
Amino Alcohol ◽  
Biomimetic Synthesis ◽  
Cross Linking ◽  
E Coli ◽  
Hplc Purification ◽  
Structural Assignment ◽  
Biosynthetic Precursor ◽  
Double Oxidation

<div>The clb gene cluster encodes the biosynthesis of metabolites known as precolibactins and colibactins. The clb pathway is found in gut commensal E. coli, and clb metabolites are thought to initiate colorectal cancer via DNA cross-linking. Precolibactin 886 (1) is one of the most complex isolated clb metabolites; it contains a 15-atom macrocycle and an unusual 5-hydroxy-3-oxazoline ring. Here we report confirmation of the structural assignment via a biomimetic synthesis of precolibactin 886 (1) proceeding through the amino alcohol 9. Double oxidation of 9 afforded the unstable α-ketoimine 2 which underwent macrocyclization to precolibactin 886 (1) upon HPLC purification (3% from 9). Studies of the putative precolibactin 886 (1) biosynthetic precursor 2, the model α-ketoimine 25, and the α-dicarbonyl 26 revealed that these compounds are susceptible to nucleophilic rupture of the C36–C37 bond. Moreover, cleavage of 2 produces other known clb metabolites or biosynthetic intermediates. This unexpected reactivity explains the difficulties in isolating full clb metabolites and accounts for the structure of a recently identified colibactin–adenine adduct. The colibactin peptidase ClbP deacylates synthetic precolibactin 886 (1) to form a non-genotoxic pyridone, suggesting precolibactin 886 (1) lies off-path of the major biosynthetic route.</div>

Simultaneous Generation of a [2×2] Grid-like Complex and a Linear Double Helicate: A Three-Level Self-Sorting Process

2019 ◽  
Author(s):  
Jean-François Ayme ◽  
Jean-Marie Lehn ◽  
Corinne Bailly ◽  
Lydia Karmazin
Keyword(s):  
Metal Complexes ◽  
Mass Spectroscopy ◽  
Metal Salts ◽  
Simultaneous Generation ◽  
X Ray ◽  
X Ray Crystallography ◽  
Sorting Process

<div>Two constitutional dynamic libraries (CDLs)—each containing two amines, two dialdehydes and two metal salts—have been found to self-sort, generating two pairs of imine-based metallosupramolecular architectures sharing no component, a [2×2] grid-like complex and a linear double helicate. These CDLs provided unique examples of a three-level self-sorting process, as only two imine-based ligand constituents, two metal complexes and two architectures were selected during their assembling out of all the possible combinations of their initial components. The metallosupramolecular architectures assembled were characterized by NMR, mass spectroscopy, and X-ray crystallography.</div>

Current Trends of Liquid Chromatography Tandem Mass Spectroscopy Use in Clinical Gynecology

2019 ◽  
Vol 70 (6) ◽  
pp. 2021-2025
Author(s):  
Aida Petca ◽  
Dan Cristian Radu ◽  
Razvan Cosmin Petca ◽  
Claudia Mehedintu ◽  
Ramona Ileana Barac ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Mass Spectroscopy ◽  
Tandem Mass ◽  
Quality Healthcare ◽  
Current Trends ◽  
Healthcare It ◽  
Liquid Chromatography Tandem Mass ◽  
Tandem Mass Spectroscopy ◽  
Technical Innovations ◽  
Hormonal Milieu

In the present environment of staggering technical innovations and increasing expectations of quality healthcare it is evident that we need to fine tune our diagnostic abilities in order to fulfil patients� demands for more efficient therapies and augmented quality of life. We are looking for current trends in clinical gynecology that make use of Liquid chromatography tandem mass spectroscopy, technology not yet employed in Romanian laboratories for the clinical practice but that is rapidly becoming the worldwide method of choice for accurate characterization of the hormonal milieu essential for the requirements of women healthcare.

Synthesis, Characterization and Application of N,N-Dimethyl-N-Sulfoethan Ammonium tetra-Chloro Aluminate: A Novel micro-Heterogeneous Cata-lyst for Synthesis of tri-Arylmethanes

2020 ◽  
Vol 17 ◽  
Author(s):  
Saeid Azimi ◽  
Niloofar Mohamadighader
Keyword(s):  
Ionic Liquid ◽  
Heterogeneous Catalyst ◽  
Mass Spectroscopy ◽  
Aromatic Aldehydes ◽  
Solid Catalyst ◽  
Sem Images ◽  
One Pot ◽  
Acidic Catalyst ◽  
Eds Analysis ◽  
Ft Ir

Abstract: A new solid catalyst was synthesized from an ionic liquid and heterogenised by changing anion reaction. The new heterogeneous acidic catalyst was characterized by SEM images, EDS analysis, AFM images, Ft-IR, HNMR, 13CNMR and Mass Spectroscopy. It was applied to synthesis of tri-arylmethanes throughout one-pot tri-component reactions among aromatic aldehydes, N,N-dimethylaniline and other carbonic nucleophiles such as anisole and indole. Hence, synthesis of convenient and inexpensive micro-heterogeneous catalyst was introduced, the efficiency of which was confirmed. Also, various useful products were synthesized throughout this simple and clean procedure.

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