Direct ring‐open mechanism of pyridine formation by replacement of one carbon in benzene with one nitrogen atom

2020 ◽  
Vol 33 (7) ◽  
Author(s):  
Haoyun Lu ◽  
Mengqi Qian ◽  
Qiang Wang ◽  
Yanhui Yang
Keyword(s):  
Nitrogen Atom ◽  
Ring Open

Structure of Diastereomeric 10-Bromo-10,11-dihydroquinines

2002 ◽  
Vol 57 (5) ◽  
pp. 586-592 ◽  
Author(s):  
Teresa Borowiak ◽  
Grzegorz Dutkiewicz ◽  
Jacek Thiel
Keyword(s):  
Hydrogen Bond ◽  
Nitrogen Atom ◽  
Unusual Case ◽  
Crystal Packing ◽  
Intermolecular Hydrogen Bond ◽  
Cinchona Alkaloid ◽  
Side Chain ◽  
Hydrogen Bond Formation ◽  
The Common ◽  
Ring Open

The absolute configurations of new chiral centers in the side chains of diastereomeric 10,11-dihydroquinines, C20H25BrN2O2, have been determined. Both diastereomers with either 10R or 10S configuration adopt the conformations in which quinuclidine nitrogen atom points away from the quinoline ring (open conformations). The bulky C3-side chain in the 10R diastereomer hinders intermolecular hydrogen bond formation to the quinuclidinic, more basic nitrogen atom. Instead, the hydrogen bond to the quinolinic N atom is formed which is an unusual case for Cinchona alkaloid crystal packing. The same bulky C3-substituent in the 10S diastereomer does not hinder the common packing mode via intermolecular hydrogen bonding to the quinuclidinic N-atom.

Nitrogen Atom Densities in Rare Gas Diluted N2 Plasmas with Capacitive and Inductive Coupling

2008 ◽  
Vol 128 (10) ◽  
pp. 615-618 ◽  
Author(s):  
Takeshi Kitajima ◽  
Akihiro Kubota ◽  
Toshiki Nakano
Keyword(s):  
Nitrogen Atom ◽  
Inductive Coupling ◽  
Rare Gas

Configuration on the C=N double bond of monosubstituted amidines and amidoximes

1989 ◽  
Vol 54 (12) ◽  
pp. 3245-3252 ◽  
Author(s):  
Bernard Tinant ◽  
Janine Dupont-Fenfau ◽  
Jean-Paul Declercq ◽  
Jaroslav Podlaha ◽  
Otto Exner
Keyword(s):  
Double Bond ◽  
Nitrogen Atom ◽  
Steric Effects ◽  
Model Compounds ◽  
X Ray ◽  
Analogous Model

Configuration on the C=N double bond of amidines and amidoximes is controlled by steric effects on the second nitrogen atom but there is a difference in the case of N’-monosubstituted derivatives: amidines prefer E configuration (conformation around the C-N bond sp) and amidoximes Z configuration (conformation ap). This was confirmed by the X-ray structures of two analogous model compounds N,N’-dimethyl-4-nitrobenzamidine (monoclinic, P21c, a = 10.855(3), b = 11.043(3), c = 8.593(3) Å, β = 105.69(2)°, V = 991.8(5) Å3, Z = 4, Dx = 1.29 g cm-3, CuKα, λ = 1.5418 Å, μ = 7.91 cm-1, F(000) = 408, T = 291 K, R = 0.065 for 1 265 observed reflections) and N’-methyl-4-nitrobenzamidoxime (monoclinic, P21/a, a = 6.699(2), b = 24.178(9), c = 6.075(2) Å, β = 106.20(3)°, V = 944.9(6) Å3, Z = 4, Dx = 1.37 g cm-3, CuKα, λ = 1.5418 Å, μ =9.22 cm-1, F(000) = 408, T = 291 K, R = 0.079 for 1 278 observed reflections).

Dirhodium-Catalyzed Chemo- and Site-Selective C–H Amidation of N,N-Dialkylanilines

Synlett ◽  
2020 ◽  
Author(s):  
Yoshihiro Ueda ◽  
Gong Chen ◽  
Kenta Arai ◽  
Kazuhiro Morisaki ◽  
Takeo Kawabata
Keyword(s):  
Nitrogen Atom ◽  
Aromatic Ring ◽  
Methyl Group ◽  
Site Selective

AbstractA method for dirhodium-catalyzed C(sp3)–H amidation of N,N-dimethylanilines was developed. Chemoselective C(sp3)–H amidation of N-methyl group proceeded exclusively in the presence of C(sp2)–H bonds of the electron-rich aromatic ring. Site-selective C(sp3)–H amidation proceeded exclusively at the N-methyl group of N-methyl-N-alkylaniline derivatives with secondary, tertiary, and benzylic C(sp3)–H bonds α to a nitrogen atom.

A new strategy for the construction of polycycles bearing a nitrogen atom on the ring fusion

2002 ◽  
Vol 43 (28) ◽  
pp. 4963-4968 ◽  
Author(s):  
Reynald Deléens ◽  
Arnaud Gautier ◽  
Serge R Piettre
Keyword(s):  
Nitrogen Atom ◽  
Ring Fusion ◽  
New Strategy

Regiospezifische Insertion von [SCN]- und [SeCN]- in die S – C- bzw. Se– C-Bindung Übergangsmetall-koordinierter Thietane und SelenetaneRegiospecific Insertion of [SCN]- and [SeCN]- in the S–C- and Se–C-Bond of Transition-Metal-Coordinated Thietanes and Selenetanes

1993 ◽  
Vol 48 (11) ◽  
pp. 1613-1620 ◽  
Author(s):  
Helmut Fischer ◽  
Claudia Kalbas ◽  
Carsten Troll ◽  
Klaus H. Fluck
Keyword(s):  
Nitrogen Atom ◽  
Transition Metal ◽  
Structure Analysis ◽  
Trans Isomer ◽  
X Ray ◽  
Tungsten Complexes ◽  
Membered Heterocycle

Pentacarbonyl(thietane)tungsten complexes react with thiocyanate, [SCN]-, and SiO2/H2O by insertion of the CN group into a S—C bond of the four-membered heterocycle, 1,3-migration of the pentacarbonyltungsten fragment and protonation of the nitrogen atom to give tungsten-coordinated thiazinthione complexes. Analogously, the reactions of a thietane tungsten complex with [SeCN]- and SiO2/H2O affords a thiazinselone complex. A selenazinthione complex is obtained from a selenetane complex and [SCN]- (+ SiO2/H2O). The insertions are regiospecific and stereoselective. The structure of the trans-isomer of a pentacarbonyl-(thiazinthione) complex has been established by X-ray structure analysis.

Chemistry of bicyclic 5-6 systems: Synthesis of oxazolo[3,2-a]pyridines and their salts with a ring-junction nitrogen atom

2019 ◽  
Vol 49 (20) ◽  
pp. 2591-2629 ◽  
Author(s):  
Mohamed Monier ◽  
Ahmed El-Mekabaty ◽  
Doaa Abdel-Latif ◽  
Khaled M. Elattar
Keyword(s):  
Nitrogen Atom ◽  
Ring Junction
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