Photoinduced deaminative strategies: Katritzky salts as alkyl radical precursors

2020 ◽  
Vol 56 (4) ◽  
pp. 503-514 ◽  
Author(s):  
José Tiago M. Correia ◽  
Vitor A. Fernandes ◽  
Bianca T. Matsuo ◽  
José A. C. Delgado ◽  
Wanderson C. de Souza ◽  
...  
Keyword(s):  
Functional Groups ◽  
Alkyl Radical ◽  
Organic Molecules ◽  
Primary Amines ◽  
Recent Developments

Primary amines are one of the most predominant functional groups found in organic molecules. This review covers the most recent developments on photocatalytic deaminative strategies by using Katritzky Salts as alkyl radical reservoirs.

Recent Strategies in Non-Heme-Type Metal Complexes-Catalyzed Site-, Chemo-, and Enantioselective C–H Oxygenations

Synthesis ◽  
2021 ◽  
Author(s):  
Daiki Doiuchi ◽  
Tatsuya Uchida
Keyword(s):  
Functional Groups ◽  
Organic Synthesis ◽  
Organic Molecules ◽  
Transition Metal Catalysts ◽  
Carbonyl Groups ◽  
Efficient Tool ◽  
Type Complex ◽  
Recent Developments ◽  
Key Functional Groups ◽  
A Site

C–H bonds are ubiquitous and abundant in organic molecules. If such C–H bonds can be converted to the desired functional groups in a site-, chemo-, diastereo-, and enantio-selective manner, the functionalization of C–H bonds would be an efficient tool for the step-, atom- and redox-economic organic synthesis. C–H oxidation is one of a typical C–H functionalization, to afford hydroxy and carbonyl groups, which are essential key functional groups in organic synthesis and biological chemistry, directly. Recently, significant developments have been made using non-heme-type transition metal catalysts. Oxygen functional groups can be introduced to not only simple hydrocarbons but also complicated natural products. In this paper, the recent developments, during the last fourteen years, of non-heme-type complex-catalyzed C–H oxidations are reviewed.

Hydration Free Energies of Organic Molecules in the FreeSolv Database Calculated with Polarized Atom In Molecules Atomic Charges and the GAFF Force Field.

2018 ◽  
Author(s):  
Maximiliano Riquelme ◽  
Alejandro Lara ◽  
David L. Mobley ◽  
Toon Vestraelen ◽  
Adelio R Matamala ◽  
...  
Keyword(s):  
Force Field ◽  
Functional Groups ◽  
Electrostatic Interactions ◽  
Organic Molecules ◽  
Force Fields ◽  
Chemical Elements ◽  
Atomic Charges ◽  
Free Energies ◽  
Molecular Systems ◽  
Solvent Model

<div>Computer simulations of bio-molecular systems often use force fields, which are combinations of simple empirical atom-based functions to describe the molecular interactions. Even though polarizable force fields give a more detailed description of intermolecular interactions, nonpolarizable force fields, developed several decades ago, are often still preferred because of their reduced computation cost. Electrostatic interactions play a major role in bio-molecular systems and are therein described by atomic point charges.</div><div>In this work, we address the performance of different atomic charges to reproduce experimental hydration free energies in the FreeSolv database in combination with the GAFF force field. Atomic charges were calculated by two atoms-in-molecules approaches, Hirshfeld-I and Minimal Basis Iterative Stockholder (MBIS). To account for polarization effects, the charges were derived from the solute's electron density computed with an implicit solvent model and the energy required to polarize the solute was added to the free energy cycle. The calculated hydration free energies were analyzed with an error model, revealing systematic errors associated with specific functional groups or chemical elements. The best agreement with the experimental data is observed for the MBIS atomic charge method, including the solvent polarization, with a root mean square error of 2.0 kcal mol<sup>-1</sup> for the 613 organic molecules studied. The largest deviation was observed for phosphor-containing molecules and the molecules with amide, ester and amine functional groups.</div>

Absorption of L-alanine and other dissolved nutrients by the spines of Paracentrotus lividus (Echinoidea)

1977 ◽  
Vol 57 (4) ◽  
pp. 1031-1045 ◽  
Author(s):  
M. E. de Burgh ◽  
A. B. West ◽  
F. Jeal
Keyword(s):  
Amino Acids ◽  
Organic Molecules ◽  
Marine Invertebrates ◽  
Analytical Techniques ◽  
Paracentrotus Lividus ◽  
Direct Absorption ◽  
Dissolved Nutrients ◽  
Recent Developments ◽  
Modern Analytical

The possibility that marine invertebrates might obtain part of their nutritional requirements by direct absorption of dissolved molecules through the epidermis has recently received considerable attention. This revival of interest in a field which had been virtually abandoned since the early part of the century was led by the findings of Stephens & Schinske (1957, 1958, 1961). Modern analytical techniques have revealed that the amount of dissolved nutrients in coastal waters is much greater than was formerly realized; total amino acids have been recorded in concentrations of up to 10-4 mole/litre in south-east Alaskan waters (Schell, 1974) and 7 x 10-5 mole/litre off Helgoland (Bohling, 1970). Direct absorption of amino acids has been conclusively established in several phyla (see reviews by Stephens, 1968,1972), and one of the major aims of current research is to show that dissolved organic molecules taken up from available concentrations could be of nutritional significance. Recent developments concerning the possible roles of uptake in marine ecosystems have been reviewed by West, de Burgh & Jeal (1977).

scholarly journals A Single-Step Synthesis of Azetidine-3-Amines

2020 ◽  
Author(s):  
Brian J Wang ◽  
Matthew Duncton
Keyword(s):  
Functional Groups ◽  
Late Stage ◽  
Single Step ◽  
Secondary Amines ◽  
High Yield ◽  
Primary Amines ◽  
Privileged Structure ◽  
One Step ◽  
Alternative Procedures ◽  
Approved Drugs

<div> <p>The azetidine group is frequently encountered within contemporary medicinal chemistry where it is viewed as a privileged structure. However, the introduction of an azetidine can be synthetically challenging. Herein, a straight-forward one step synthesis of azetidine-3-amines, starting from a bench stable, commercial material is presented. The reaction tolerates functional groups commonly encountered in biological-, medicinal- and agro-chemistry, and proceeds in moderate-to-high yield with secondary amines, and moderate-to-low yield with primary amines. The methodology compares favorably to recent alternative procedures and can be utilized in “any-stage” functionalization, including late-stage azetidinylation of approved drugs and other compounds with pharmacological activity.</p> </div>

Recent developments in sulfur–carbon bond formation reaction involving thiosulfates

2017 ◽  
Vol 15 (9) ◽  
pp. 1942-1946 ◽  
Author(s):  
Zongjun Qiao ◽  
Xuefeng Jiang
Keyword(s):  
Pharmaceutical Industry ◽  
Organic Molecules ◽  
Materials Science ◽  
Bond Formation ◽  
Food Chemistry ◽  
Formation Reaction ◽  
Carbon Bond ◽  
Recent Developments ◽  
Sulfur Containing

Sulfur–carbon bond construction has gained great attention recently since sulfur-containing organic molecules serve important functions in the pharmaceutical industry, agrochemistry, food chemistry, and materials science.

ChemInform Abstract: Recent Developments in Chemical Deprotection of Ester Functional Groups

ChemInform ◽  
2010 ◽  
Vol 24 (36) ◽  
pp. no-no
Author(s):  
C. J. SALOMON ◽  
E. G. MATA ◽  
O. A. MASCARETTI
Keyword(s):  
Functional Groups ◽  
Recent Developments

Frameworks of Transition Metals and Linkers with Two or More Functional Groups

2000 ◽  
Vol 658 ◽  
Author(s):  
Slavi C. Sevov
Keyword(s):  
Amino Acids ◽  
Transition Metals ◽  
Functional Groups ◽  
Organic Molecules ◽  
Layered Structures ◽  
Amino Groups ◽  
Effect Of Ph ◽  
Open Framework ◽  
Acidic Conditions ◽  
New Compounds

ABSTRACTHybrid inorganic/organic materials with open-framework or layered structures are known for many transition metals linked by functionalized organic molecules such as organic diphosphonates, polycarboxylates, polynitriles, etc., species with more than one equivalent functional groups. We have studied the effect of pH on such a system of cobaltmethylenediphosphonate and report three new compounds, Na3Co[(O3PCH2PO3)(OH)],Na2Co(O3PCH2PO3)•H2O, and Co2[(O3PCH2PO3)(H2O)], that form at very basic, moderately basic, and acidic conditions, respectively. More interestingstructural chemistry should be expected from linkers with two or more different functionalities. Both the carboxylic and phosphonic groups in carboxyethylphosphonic acid are used to coordinate to cobalt or calcium atoms in the new compounds Co3(O3PCH2CH2COO)2•6H2O and Ca(O3PCH2CH2COOH)•H2O. Taking one more step further in complexity we have also studied linkers with three different functional groups, phosphonated amino acids. The structures of two new compounds, Zn(O3PCH2CH(NH3)COO) and Zn(O3PCH2CH2CH(NH3)COO), are threedimensional frameworks made of zinccoordinated by both the carboxylic and phosphonic ends of the organic molecules. The amino groups are protonated and terminal in the voids of the frameworks.

scholarly journals Recent developments of novel matrices and on-tissue chemical derivatization reagents for MALDI-MSI

2020 ◽  
Author(s):  
Qiuqin Zhou ◽  
Annabelle Fülöp ◽  
Carsten Hopf
Keyword(s):  
Mass Spectrometry Imaging ◽  
Organic Molecules ◽  
Resolving Power ◽  
Ionization Mass ◽  
Chemical Derivatization ◽  
Small Organic Molecules ◽  
Tissue Sections ◽  
Matrix Properties ◽  
Organic Matrices ◽  
Recent Developments

AbstractMatrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) is a fast-growing technique for visualization of the spatial distribution of the small molecular and macromolecular biomolecules in tissue sections. Challenges in MALDI-MSI, such as poor sensitivity for some classes of molecules or limited specificity, for instance resulting from the presence of isobaric molecules or limited resolving power of the instrument, have encouraged the MSI scientific community to improve MALDI-MSI sample preparation workflows with innovations in chemistry. Recent developments of novel small organic MALDI matrices play a part in the improvement of image quality and the expansion of the application areas of MALDI-MSI. This includes rationally designed/synthesized as well as commercially available small organic molecules whose superior matrix properties in comparison with common matrices have only recently been discovered. Furthermore, on-tissue chemical derivatization (OTCD) processes get more focused attention, because of their advantages for localization of poorly ionizable metabolites and their‚ in several cases‚ more specific imaging of metabolites in tissue sections. This review will provide an overview about the latest developments of novel small organic matrices and on-tissue chemical derivatization reagents for MALDI-MSI.

scholarly journals Synthesis of Organic Compounds in the Circumstellar Environment

2004 ◽  
Vol 213 ◽  
pp. 181-184
Author(s):  
Sun Kwok
Keyword(s):  
Organic Molecules ◽  
Chemical Nature ◽  
Planetary Nebulae ◽  
Infrared Emission ◽  
Aromatic Rings ◽  
Carbon Stars ◽  
Recent Developments ◽  
Molecular Synthesis ◽  
Bending Modes ◽  
Circumstellar Environment

Recent developments in infrared spectroscopy have made possible the detection of the stretching and bending modes of organic molecules in space. Infrared emission bands of the C-C and C-H stretching and bending modes of aromatic compounds have been widely observed in carbon-rich planetary nebulae, the descendents of carbon stars. Infrared spectra of the transition objects between carbon stars and planetary nebulae, called proto-planetary nebulae, have shown definite signatures of a variety of aliphatic side-groups attached to aromatic rings. This suggests that molecular synthesis is actively ongoing in the circumstellar environment and the chemical nature of these compounds evolve over time scales as short as several hundred years.

Recent developments in chemical deprotection of ester functional groups

Tetrahedron ◽  
1993 ◽  
Vol 49 (18) ◽  
pp. 3691-3734 ◽  
Author(s):  
Claudio J. Salomon ◽  
Ernesto G. Mata ◽  
Oreste A. Mascaretti
Keyword(s):  
Functional Groups ◽  
Recent Developments
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