[Hg5(μ2-Cy2P)5(O3SCF3)5] and [Hg5(μ2-Cy2P)5(SO4H)5]: compounds involving the new ten-membered ring system (Hg-P)5

1983 ◽  
Vol 241 (3) ◽  
pp. 281-287 ◽  
Author(s):  
Paul Peringer ◽  
Johann Eichbichler
Keyword(s):  
Ring System ◽  
Membered Ring

scholarly journals Homocoupling Reactions of Azoles and Their Applications in Coordination Chemistry

Molecules ◽  
2020 ◽  
Vol 25 (24) ◽  
pp. 5950
Author(s):  
Steffen B. Mogensen ◽  
Mercedes K. Taylor ◽  
Ji-Woong Lee
Keyword(s):  
Coordination Chemistry ◽  
Reaction Mechanisms ◽  
Metal Organic Frameworks ◽  
Ring System ◽  
Membered Ring ◽  
Materials Chemistry ◽  
Structural Class ◽  
Basic Nitrogen ◽  
Metal Organic ◽  
Metal Catalyzed

Pyrazole, a member of the structural class of azoles, exhibits molecular properties of interest in pharmaceuticals and materials chemistry, owing to the two adjacent nitrogen atoms in the five-membered ring system. The weakly basic nitrogen atoms of deprotonated pyrazoles have been applied in coordination chemistry, particularly to access coordination polymers and metal-organic frameworks, and homocoupling reactions can in principle provide facile access to bipyrazole ligands. In this context, we summarize recent advances in homocoupling reactions of pyrazoles and other types of azoles (imidazoles, triazoles and tetrazoles) to highlight the utility of homocoupling reactions in synthesizing symmetric bi-heteroaryl systems compared with traditional synthesis. Metal-free reactions and transition-metal catalyzed homocoupling reactions are discussed with reaction mechanisms in detail.

Untersuchungen zur Ringkontraktion am 1,4-Dithia-2,6-diaza-3,5-diborinan-System/ Studies on Ring Contraction of the l,4-Dithia-2,6-diaza-3,5-diborinane System

1988 ◽  
Vol 43 (8) ◽  
pp. 959-962 ◽  
Author(s):  
Carl Habben ◽  
Anton Meiler ◽  
Stefan Pusch
Keyword(s):  
Mass Spectra ◽  
Ring System ◽  
Membered Ring ◽  
Ring Contraction ◽  
C Nmr

AbstractThe 1,4-dithia-2,6-diaza-3,5-diborinanes 1a-d react with elemental sodium with formation of the 1,3-diaza-2,4-diboretidines 2a-d. By use of more sodium in case of 1 d or 3,5-bis(diethylamino)- 2-cyclohexyl-6-trimethylsilyldiborinane, the 1,3-thiaza-2,4-diboretidines 3 were formed. 3.5-Dimethyl-2,6-bis(trimethylsilyl)-1,4-dithia-2,6-diaza-3,5-diborinane gives the borazine 4, The reaction of di-t-butyl-sulfurdiimide with 2,6-di-t-butyl-3,5-dimethyl-1,4-dithia-2,6-diaza-3,5-diborinane leads by ring contraction to the four-membered ring system 5. 1H, 11B, 13C NMR and mass spectra are reported and discussed.

Reaktion von N-Trimethylsilyl-N′(N″ -trimethylsilylammodiphenylphosphoranylidenimino) sulfamid mit Wolframoxitetrachlorid und die Struktur von (Cl3WNPPh2N)2 Reaction of N-Trimethylsilyl-N′(N″ -trimethylsilylaminodiphenylphosphoranylidene)sulfamide with Tungstenoxitetrachloride and the Structure of (Cl3WNPPh2N)2

1992 ◽  
Vol 47 (2) ◽  
pp. 171-174 ◽  
Author(s):  
H. W. Roesky ◽  
T. Raubold ◽  
M. Noltemeyer ◽  
M. Witt ◽  
R. Bohra
Keyword(s):  
Molecular Structure ◽  
Structure Analysis ◽  
Ring System ◽  
Membered Ring ◽  
X Ray

1The reaction of ClSO2N = PPh2Cl () with NH3 yields H2NSO2N = PPh2NH2 (2).This compound is converted to Me3Si(H)NSO2N = PPh2N(H)SiMe3 (3) by Me3SiNMe2. 3 reacts with WOCl4 under elimination of (Me3Si)2O and ClSO2NH2 to yield the eight-membered ring system (Cl3WNPPh2N)2 (4).The molecular structure of 4 was investigated by an X-ray structure analysis.

Das dynamische Verhalten des 1-Methyl-1-benzothiepinium-Ringsystems/The Dynamic Behaviour of the 1-Methyl-1-benzothiepinium Ring System

1981 ◽  
Vol 36 (8) ◽  
pp. 974-977 ◽  
Author(s):  
Hans Hofmann ◽  
Franz Dickert
Keyword(s):  
Nmr Spectroscopy ◽  
Room Temperature ◽  
Dynamic Behaviour ◽  
Ring System ◽  
Membered Ring ◽  
Ring Inversion ◽  
Methyl Group ◽  
H Nmr ◽  
Pyramidal Inversion ◽  
Mutual Conversion

Abstract By 1H NMR spectroscopy the stereochemistry of the 1-methyl-1-benzothiepinium ring system was investigated both in thermodynamic and kinetic respects. It was shown that in solution a rapid mutual conversion of the boat shaped seven membered ring system with exo-respectively endo-S-methyl group occurs via a ring inversion and not by a pyramidal inversion at the sulfonium ion. At room temperature predominantly the conformation with the exo-S-methyl group is present.

scholarly journals Synthesis of Taxane ABC Tricyclic Skeleton from Lycoctonine

2012 ◽  
Vol 7 (6) ◽  
pp. 1934578X1200700 ◽  
Author(s):  
Xiao-Xia Liang ◽  
Pei Tang ◽  
Qiao-Hong Chen ◽  
Feng-Peng Wang
Keyword(s):  
Ring System ◽  
Membered Ring ◽  
Diterpenoid Alkaloid ◽  
Distinctive Features ◽  
Pinacol Rearrangement

A new conversional synthesis of the ABC ring system of taxoids from the C19-diterpenoid alkaloid lycoctonine was developed in 6 steps with 2% overall yield. The distinctive features of the conversion include pinacol rearrangement, enlargement of ring B, and opening of a four-membered ring.

Improvement in zinc complexes bearing Schiff base in ring-opening polymerization of ε-caprolactone: A five-membered ring system

Polymer ◽  
2019 ◽  
Vol 182 ◽  
pp. 121812 ◽  
Author(s):  
Feng-Jie Lai ◽  
Li-Ling Chiu ◽  
Chieh-Ling Lee ◽  
Wei-Yi Lu ◽  
Yi-Chun Lai ◽  
...  
Keyword(s):  
Schiff Base ◽  
Ring Opening ◽  
Ring Opening Polymerization ◽  
Ring System ◽  
Membered Ring ◽  
Zinc Complexes

scholarly journals Differenzelektronendichte im gefalteten 2 π-aromatischen System eines 1,3-Dihydro-1,3-diborets / Difference Electron Density in a Folded 2π-Aromatic System of a 1,3-Dihydro-1,3-diborete

1991 ◽  
Vol 46 (12) ◽  
pp. 1621-1624 ◽  
Author(s):  
Hermann Irngartinger ◽  
Jürgen Hauck ◽  
Walter Siebert ◽  
Manfred Hildenbrand
Keyword(s):  
Crystal Structure ◽  
Density Distribution ◽  
Electron Density ◽  
Electron Density Distribution ◽  
Ring System ◽  
Membered Ring ◽  
Aromatic System ◽  
Difference Electron Density ◽  
Folding Angle

The crystal structure and the X—X difference electron density distribution of 1,3-bis(diisopropylamino)-1,3,dihydro-1,3-diborete (1) has been determined at the temperature of 107 K. Both π-electrons of the folded aromatic four membered ring system (folding angle 47.6°) are uniformly distributed on the four ring bonds with equal lengths (B—C 1.524 A). These bonds are significantly bent.

scholarly journals Notizen: Versuche zur Kondensation von Hexamethyl-4.4-bis(methylamino)cyclo-1.2.4-trisila-diazan / Attempts for the Condensation of Hexamethyl-4.4-bis(methylamino)cyclo-1,2,4-trisila-diazane

1977 ◽  
Vol 32 (8) ◽  
pp. 954-955 ◽  
Author(s):  
Merten Schlingmann ◽  
Ulrich Wannagat
Keyword(s):  
Title Compound ◽  
Ring System ◽  
Membered Ring

It was not possible to condensate the Si(NHCH3)2 unit of the title compound to a six-membered ring system. Instead a novel dispiro compound with an OSO unit inside the framework was obtained using (NH4)2SO4 as a catalyst (Scheme 1).

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