Aromatic amides. VIII. Z,E Isomer ratios and stereochemistry about aryl-nitrogen bonds in N-aryl amides and thioamides

1974 ◽  
Vol 27 (12) ◽  
pp. 2611 ◽  
Author(s):  
DL Bate ◽  
ID Rae
Keyword(s):  
Amide Group ◽  
Isomer Ratio ◽  
Ring Plane ◽  
Nitrogen Bonds ◽  
Electron Withdrawing Substituents

For 4?-substituted 2?,6?-diethylacetanilides, the Z/E isomer ratio depends on the nature of the 4?- substituent, the Z isomer being relatively favoured by electron-withdrawing substituents. The acyla- tion shifts of the ortho aromatic protons for 4?-substituted thiopivalanilides are greatest when the substituent is electron- withdrawing. These relationships complement the previously observed changes in isomer ratios of thioamides and acylation shifts of amides. It is proposed that the Z isomer is more nearly planar when the 4?- substituent is electron-withdrawing. As the substituent becomes more electron-releasing, the amide group is able to twist more out of the ring plane and the Z isomer is destabilized, relative to the E isomer, by n-π electron repulsions.

scholarly journals Highly selective electrochemical fluorination of dithioacetal derivatives bearing electron-withdrawing substituents at the position α to the sulfur atom using poly(HF) salts

2015 ◽  
Vol 11 ◽  
pp. 85-91 ◽  
Author(s):  
Bin Yin ◽  
Shinsuke Inagi ◽  
Toshio Fuchigami
Keyword(s):  
Sulfur Atom ◽  
Nitrile Group ◽  
Amide Group ◽  
Sharp Contrast ◽  
Product Selectivity ◽  
Electrochemical Fluorination ◽  
Weak Electron ◽  
Electron Withdrawing Substituents

Anodic fluorination of dithioacetals bearing electron-withdrawing ester, acetyl, amide, and nitrile groups at their α-positions was comparatively studied using various supporting poly(HF) salts like Et3N·nHF (n = 3–5) and Et4NF·nHF (n = 3–5). In the former two cases, the corresponding α-fluorination products or fluorodesulfurization products were obtained selectively depending on supporting poly(HF) salts used. In sharp contrast, in the latter two cases, fluorination product selectivity was strongly affected by the electron-withdrawing ability of α-substituents: A dithioacetal bearing a relatively weak electron-withdrawing amide group provided a fluorodesulfurization product selectively while a dithioacetal having a strongly electron-withdrawing nitrile group gave the α-fluorination product predominantly regardless of the poly(HF) salts used.

scholarly journals rac-1-(2-Aminocarbonyl-2-bromoethyl)pyridinium bromide

2012 ◽  
Vol 68 (6) ◽  
pp. o1666-o1666
Author(s):  
Robert Köppen ◽  
Franziska Emmerling ◽  
Matthias Koch
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Title Compound ◽  
Pyridine Ring ◽  
Acid Amide ◽  
Amide Group ◽  
Ring Plane ◽  
Pyridinium Bromide ◽  
Compound C ◽  
Inclined Angle

In the crystal structure of the title compound, C8H10BrN2O+·Br−, intermolecular N—H...Br hydrogen bonds link the molecules into infinite chains along [001]. The inclined angle between the pyridine ring plane and the plane defined by the acid amide group is 63.97 (4)°.

A study of cis-trans isomerism and conformational preferences of thioanilides

1967 ◽  
Vol 45 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Ian D. Rae
Keyword(s):  
Hydrogen Bonding ◽  
Proton Magnetic Resonance ◽  
Proton Magnetic Resonance Spectroscopy ◽  
Resonance Spectroscopy ◽  
Isomer Ratio ◽  
Ring Plane ◽  
Thioamide Group ◽  
Conformational Preferences ◽  
Ortho Substituent ◽  
Do So

In thioanilides, cis-trans isomerism has been clearly differentiated from thioamide – thiolimidic acid tautomerism. The isomer ratio has been related to structural and environmental influences on the thioamide group by means of infrared and proton magnetic resonance spectroscopy. In the thioanilides, the thioamide group does not lie in the ring plane unless constrained to do so by hydrogen bonding between the thioamide proton and a suitable ortho substituent.

scholarly journals Intra- and intermolecular Se...X (X = Se, O) interactions in selenium-containing heterocycles: 3-benzoylimino-5-(morpholin-4-yl)-1,2,4-diselenazole

2014 ◽  
Vol 70 (5) ◽  
pp. 482-487 ◽  
Author(s):  
Anthony Linden ◽  
Yuehui Zhou ◽  
Heinz Heimgartner
Keyword(s):  
Bond Length ◽  
Title Compound ◽  
Phenyl Ring ◽  
Significant Interaction ◽  
Double Helix ◽  
Three Dimensional ◽  
Amide Group ◽  
Supramolecular Framework ◽  
Ring Plane ◽  
Group Form

In the selenium-containing heterocyclic title compound {systematic name: N-[5-(morpholin-4-yl)-3H-1,2,4-diselenazol-3-ylidene]benzamide}, C13H13N3O2Se2, the five-membered 1,2,4-diselenazole ring and the amide group form a planar unit, but the phenyl ring plane is twisted by 22.12 (19)° relative to this plane. The five consecutive N—C bond lengths are all of similar lengths [1.316 (6)–1.358 (6) Å], indicating substantial delocalization along these bonds. The Se...O distance of 2.302 (3) Å, combined with a longer than usual amide C=O bond of 2.252 (5) Å, suggest a significant interaction between the amide O atom and its adjacent Se atom. An analysis of related structures containing an Se—Se...X unit (X = Se, S, O) shows a strong correlation between the Se—Se bond length and the strength of the Se...X interaction. When X = O, the strength of the Se...O interaction also correlates with the carbonyl C=O bond length. Weak intermolecular Se...Se, Se...O, C—H...O, C—H...π and π–π interactions each serve to link the molecules into ribbons or chains, with the C—H...O motif being a double helix, while the combination of all interactions generates the overall three-dimensional supramolecular framework.

scholarly journals N-(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)-2-(4-nitrophenyl)acetamide

2014 ◽  
Vol 70 (6) ◽  
pp. o636-o637 ◽  
Author(s):  
Manpreet Kaur ◽  
Jerry P. Jasinski ◽  
H. S. Yathirajan ◽  
B. Narayana ◽  
K. Byrappa
Keyword(s):  
Hydrogen Bonds ◽  
Torsion Angle ◽  
Pyrazole Ring ◽  
Amide Group ◽  
Maximum Deviation ◽  
Ring Plane ◽  
Compound C ◽  
Phenyl Rings ◽  
The Mean ◽  
Graph Set

In the title compound, C19H18N4O4, the nitrophenyl and phenyl rings are twisted by 67.0 (6) and 37.4 (4)°, respectively, with respect to the pyrazole ring plane [maximum deviation = 0.0042 (16) Å]. The dihedral angle between the mean planes of the phenyl rings is 59.3 (3)°. The amide group, with a C—N—C—C torsion angle of 177.54 (13)°, is twisted away from the plane of the pyrazole ring in an antiperiplanar conformation. In the crystal, N—H...O hydrogen bonds involving the carbonyl group on the pyrazole ring and the amide group, together with weak C—H...O interactions formingR22(10) graph-set motifs, link the molecules into chains along [100]. Additional weak C—H...O interactions involving the nitrophenyl rings further link the molecules along [001], also formingR22(10) graph-set motifs, thereby generating (010) layers.

Rendez vous with Saturn's rings

1984 ◽  
Vol 75 ◽  
pp. 743-759 ◽  
Author(s):  
Kerry T. Nock
Keyword(s):  
Solar Energy ◽  
Electric Propulsion ◽  
Power Source ◽  
Propulsion System ◽  
Low Thrust ◽  
Ring Plane ◽  
The Earth ◽  
Total Impulse ◽  
Saturn's Rings

ABSTRACTA mission to rendezvous with the rings of Saturn is studied with regard to science rationale and instrumentation and engineering feasibility and design. Future detailedin situexploration of the rings of Saturn will require spacecraft systems with enormous propulsive capability. NASA is currently studying the critical technologies for just such a system, called Nuclear Electric Propulsion (NEP). Electric propulsion is the only technology which can effectively provide the required total impulse for this demanding mission. Furthermore, the power source must be nuclear because the solar energy reaching Saturn is only 1% of that at the Earth. An important aspect of this mission is the ability of the low thrust propulsion system to continuously boost the spacecraft above the ring plane as it spirals in toward Saturn, thus enabling scientific measurements of ring particles from only a few kilometers.

The Nature of S-N Bonding in Sulfonamides and Related Compounds: Insights into π-Bonding Contributions from Sulfur K-Edge XAS

2020 ◽  
Author(s):  
Tulin Okbinoglu ◽  
Pierre Kennepohl
Keyword(s):  
Density Functional ◽  
Chemical Properties ◽  
Functional Theory ◽  
Rotational Barriers ◽  
Td Dft ◽  
Nitrogen Bonds ◽  
X Ray Absorption ◽  
Related Compounds ◽  
And Chemical Properties

Molecules containing sulfur-nitrogen bonds, like sulfonamides, have long been of interest due to their many uses and chemical properties. Understanding the factors that cause sulfonamide reactivity is important, yet their continues to be controversy regarding the relevance of S-N π bonding in describing these species. In this paper, we use sulfur K-edge x-ray absorption spectroscopy (XAS) in conjunction with density functional theory (DFT) to explore the role of S<sub>3p</sub> contributions to π-bonding in sulfonamides, sulfinamides and sulfenamides. We explore the nature of electron distribution of the sulfur atom and its nearest neighbors and extend the scope to explore the effects on rotational barriers along the sulfur-nitrogen axis. The experimental XAS data together with TD-DFT calculations confirm that sulfonamides, and the other sulfinated amides in this series, have essentially no S-N π bonding involving S<sub>3p</sub> contributions and that electron repulsion and is the dominant force that affect rotational barriers.

Photocatalytic Alkylation of Pyrroles and Indoles with α-Diazo Esters

2019 ◽  
Author(s):  
Łukasz Ciszewski ◽  
Jakub Durka ◽  
Dorota Gryko
Keyword(s):  
Aromatic Compounds ◽  
Reaction Pathway ◽  
Alkylating Agents ◽  
Catalytic Amount ◽  
Radical Formation ◽  
Reaction Selectivity ◽  
Diazo Esters ◽  
Electron Withdrawing Substituents

This article describes direct photoalkylation of electron-rich aromatic compounds with diazo compoiunds. C-2 alkylated indoles and pyrroles are obtained with good yields even though the photocatalyst (Ru(bpy)3Cl2) loading is as low as 0.075 mol %. For substrates bearing electron-withdrawing substituents the addition of a catalytic amount of N,N-dimethyl-4-methoxyaniline is required. Both EWG-EWG and EWG-EDG substituted diazo esters are suitable as alkylating agents. The reaction selectivity and mechanistic experiments suggest that carbenes/carbenoid intermediates are not involved in the reaction pathway, instead radical formation is proposed.

Synthesis and Biological Properties of some New Lead Sulphonamide and Carboxamide Scaffolds Bearing Coumarin Moiety (Mini Review)

2020 ◽  
Vol 20 ◽  
Author(s):  
Cosmas Chinweike Eze ◽  
Mercy Amarachukwu Ezeokonkwo ◽  
Benjamin Ebere Ezema ◽  
Abraham Efeturi Onoabedje ◽  
David Izuchukwu Ugwu
Keyword(s):  
Biological Properties ◽  
Therapeutic Agents ◽  
Amide Group ◽  
Pharmacological Properties ◽  
Important Class ◽  
Synthetic Route ◽  
Therapeutic Activities

: Coumarin, sulphonamide and amide scaffolds exhibit diverse pharmacological features and constitute an important class of therapeutic agents. In this review, we have discussed the synthesis, biological properties, and SAR of coumarins containing sulphonamide or amide group in the last seven years. Many reviews on the therapeutic activities of coumarins, sulphonamides, and amides have been published, hence the authors focused on coumarin-linked sulphonamide or amide scaffolds. The review provides information on the synthetic route to new coumarins containing sulphonamide or amide groups with improved pharmacological properties.

(Substituted)-benzo[b]thiophene-4-carboxamide Synthesis and Antiproliferative Activity Study

2020 ◽  
Vol 17 (5) ◽  
pp. 563-573 ◽  
Author(s):  
Chandrakant Dhondiram Pawar ◽  
Dattatraya Navnath Pansare ◽  
Devanand Baburao Shinde
Keyword(s):  
Anticancer Activity ◽  
Cell Lines ◽  
Proliferative Activity ◽  
Thiophene Ring ◽  
Amide Group ◽  
Peptide Coupling ◽  
Ic50 Value ◽  
Important Building Block ◽  
Mcf 7

Background: Thiophene ring forms important building block in medicinal chemistry. Literature reveals that thiophene ring in combination with different groups shows different activity. By keeping these things in mind we have designed and synthesized a new series of amide and sulfonamide coupled thiophene. A series of novel substituted 3-sulfamoylbenzo[b]thiophene-4- carboxamide molecules containing sulfonamide and amide group were designed, synthesized and used for anti-proliferative activity study. Methods: The final compounds 16-36 were synthesized by using series of reactions comprising sulfonation, sulfonamide coupling, hydrolysis and peptide coupling. The yields of compounds 16- 36 are in the range of 90-98%. The structures of the synthesized compounds were elucidated and confirmed by 1H NMR, 13C NMR, LCMS and the purity was checked through HPLC analysis. The compounds were further tested for their in vitro anticancer activity against a series of cell lines A549, HeLa, MCF-7 and Du-145. Results: The intermediates 8-13, 15 and final compounds 16-36 were synthesized in good yields. The synthesized compounds were further tested for their anticancer activity and most of compounds showed moderate to good anticancer activity against all four cell lines. Conclusion: We have synthesized 21 compounds and were screened for anticancer activity against MCF-7, HeLa, A-549 and Du-145 cancer cell lines. Most of the compounds were active for tested cell lines with IC50 value in the range of 1.81 to 9.73 μM. The compounds 18, 19, 21, 25, 30, 31 and 33 are most active in cell line data with IC50 value in the range of 1.81 to 2.52 μM.

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