Betaine formation from the reactions of N-heterocyclic carbenes with polarized alkenes

2021 ◽  
Author(s):  
Hamed Ghanbari ◽  
Katherine N. Robertson ◽  
Jason Clyburne ◽  
Ebrahim Soleimani
Keyword(s):  
Crystal Structures ◽  
Heterocyclic Carbenes ◽  
Double Bonds ◽  
One Pot ◽  
Imidazolium Salt ◽  
X Ray ◽  
Full Characterization

N-heterocyclic carbenes [1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene 1a (IMes) or 1,3-bis(2,6-di-iso-propylphenyl)imidazolidene 1b (SIPr)] react with the polarized alkenes 2 and 4 to form the crystalline betaines 3a, 3b and 5a. Furthermore, a one-pot reaction between an aldehyde, malonitrile, and an imidazolium salt of an N-heterocyclic carbene has been developed for the efficient preparation of betaine 5a without isolation of the free carbene. Full characterization data, including X-ray crystal structures, is reported for the three synthesized betaines. The structures of the betaines 3a, 3b and 5a shed new light on the initial products formed in the reactions between N-heterocyclic carbenes and compounds containing polarized double bonds.

Synthesen und Strukturen von 2,5-Bis(2-arylvinyl)-1,4-benzochinonen und deren photochemisches Verhalten im Kristall / Syntheses and Crystal Structures of 2,5-Bis(2-arylvinyl)-1,4-benzoquinones and their Photochemical Reactivity in the Crystalline State

1993 ◽  
Vol 48 (10) ◽  
pp. 1411-1418 ◽  
Author(s):  
Hermann Irngartinger ◽  
Jochen Lichtenthäler ◽  
Dieter Fenske ◽  
Gerhard Baum
Keyword(s):  
Crystal Structures ◽  
Anodic Oxidation ◽  
Crystalline State ◽  
Double Bonds ◽  
Resonance Structures ◽  
Photochemical Reactivity ◽  
X Ray ◽  
Bond Lengths ◽  
Intermolecular Distances ◽  
Hydrolysis Of

The 2,5-bis(2-arylvinyl)-1,4-benzoquinones 1a-1e are formed from hydrolysis of their corresponding ketals 5 which are generated by anodic oxidation of the corresponding 1,4-dimethoxybenzene derivatives 4. The crystal structures of the quinone compounds 1a, 1d and 1e have been determined by X-ray analyses. The bond lengths of the quinone system are influenced by polar resonance structures. An α-type packing mode is observed for the three crystal structures of compounds 1. The vinylic double bonds have short intermolecular distances (1a: 4.417(5), 1d: 3.653(2), 1e: 4.224(5) Å). Only the crystals of 1d with the shortest contacts are photoreactive

1,3-Di(alkoxy)imidazolium-based Ionic Liquids: Improved Synthesis and Crystal Structures

2013 ◽  
Vol 66 (3) ◽  
pp. 391 ◽  
Author(s):  
Carmen Froschauer ◽  
Robert Salchner ◽  
Gerhard Laus ◽  
Hedda K. Weber ◽  
Richard Tessadri ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Single Crystal ◽  
Crystal Structures ◽  
Structure Determination ◽  
One Pot ◽  
Synthetic Pathway ◽  
X Ray

A new and convenient synthetic pathway to 1,3-di(alkoxy)imidazolium bis(trifluoromethylsulfonyl)amides and novel 1,3-di(alkoxy)imidazolium tetrachloroferrates was developed. As an intermediate isolation step of the respective hexafluorophosphates was required in previously reported preparations, they suffered from low overall yields and additional expense. The use of FeCl3/HCl resulted in substantially improved yields and allows one-pot preparations with good scalability. Results of single-crystal X-ray structure determination of the new tetrachloroferrate salts are discussed.

X-Ray Crystal Structures of 10π- and 14π-Electron Pyrido-Anellated N-Heterocyclic Carbenes.

ChemInform ◽  
2006 ◽  
Vol 37 (30) ◽  
Author(s):  
Michael Nonnenmacher ◽  
Doris Kunz ◽  
Frank Rominger ◽  
Thomas Oeser
Keyword(s):  
Crystal Structures ◽  
Heterocyclic Carbenes ◽  
X Ray
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