Study on the enolization of alkylation of cis and trans 2-tert-5-X-1,3-dioxanes (X = CO2CH3, CHO, COPh, NO2, and CN). Evidence for stereoelectronic control

1986 ◽  
Vol 64 (9) ◽  
pp. 1788-1794 ◽  
Author(s):  
Alexis Ndibwami ◽  
Pierre Deslongchamps
Keyword(s):  
Alkylating Agent ◽  
Trans Isomers ◽  
Tert Butyl ◽  
Cyclohexane Carboxylate ◽  
Stereoelectronic Control ◽  
Cis And Trans

Alkylation of 2-tert-butyl-5-X-1,3-dioxanes (X = CO2CH3, COPh, and NO2) was studied. Products resulting from an equatorial approach of the alkylating agent are preferentially formed when X = CO2CH3 and NO2. Also, the cis isomers that have an equatorial hydrogen at C-5 were found to deprotonate at a faster rate than the trans isomers when X = CO2CH3, COPh, CHO, and CN. These results are compared with those obtained with methyl 2-tert-butyl cyclohexane carboxylate and are interpreted by taking into account stereoelectronic principles.

cis/trans Isomers of Dimeric Dialkylaluminum and Dialkylgallium Hydrazides

2008 ◽  
Vol 63 (10) ◽  
pp. 1149-1154 ◽  
Author(s):  
Werner Uhl ◽  
Andreas Vogelpohl
Keyword(s):  
Solid State ◽  
Equilibrium Mixture ◽  
Trans Configuration ◽  
Trans Isomers ◽  
Tert Butyl ◽  
Hydrazine Derivatives ◽  
Piperidine Derivative ◽  
Cis And Trans Isomers ◽  
Gallium Hydride ◽  
Cis And Trans

AbstractThe reaction of diethylaluminum hydride with the hydrazine derivatives 1-aminopyrrole and 1- aminopiperidine afforded the corresponding dialkylaluminum hydrazides (1 and 2) by the release of elemental hydrogen. Both products are dimeric in the solid state. While 1 adopts a cis arrangement of the pyrrole groups, a trans configuration was determined for the piperidine compound 2. Only 1 gives an equilibrium mixture of cis and trans isomers in solution. Similar compounds (3 and 4) were obtained by the treatment of the same hydrazines with di(tert-butyl)gallium hydride. Both products exhibit the trans configuration in the solid state, but interestingly only the piperidine derivative 4 shows a cis/trans equilibrium in solution.

Radical-Initiated Hydrosilylation-Cyclization Reactions of Bis(vinyldimethylsilyl) Compounds, CH2=CH(CH3)2SiXSi(CH3)2CH=CH2 (X = O, CH2, NH, NCH3, NSi(CH3)3

1994 ◽  
Vol 49 (12) ◽  
pp. 1818-1826 ◽  
Author(s):  
Dietmar Seyferth ◽  
Holger Friedrich ◽  
Shane W. Krska
Keyword(s):  
Membered Ring ◽  
Trans Isomers ◽  
Cyclization Reactions ◽  
Tert Butyl ◽  
Cis And Trans Isomers ◽  
Butyl Peroxide ◽  
Cis And Trans

The di-tert-butyl peroxide-initiated reactions of triethyl- and tri-n-propylsilane with bis-(vinyldim ethylsilyl) compounds, CH2=CH(CH3)2SiXSi(CH3)2CH=CH2(X-O,CH2, NH,NCH3 and NSiMe3) resulted in hydrosilylation-cyclization to give mixtures of trialkylsilylm ethyl-substituted disilacyclohexanes and trialkylsilylm ethyl-substituted disilacyclopentanes. The ratio of six-membered to five-membered ring products obtained is dependent on the linking group X and decreased in the order X=O>CH2>NH>NCH3. For X = NSiMe3 only a mixture of the cis and trans isomers of the five-membered ring product was obtained.

scholarly journals Identification of Anthocyanin Compounds in Butterfly Pea Flowers (Clitoria ternatea L.) by Ultra Performance Liquid Chromatography/Ultraviolet Coupled to Mass Spectrometry

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4539
Author(s):  
Nguyen Minh Thuy ◽  
Vo Minh ◽  
Tran Ben ◽  
My Tuyen Thi Nguyen ◽  
Ho Ha ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Ultra Performance Liquid Chromatography ◽  
Negative Ion ◽  
Trans Isomers ◽  
Clitoria Ternatea ◽  
Flower Extract ◽  
Cis And Trans Isomers ◽  
Butterfly Pea ◽  
Cis And Trans

Butterfly pea flower have great sensory attraction, but they have not yet been used widely in Vietnam. Extracts of butterfly pea flowers can be used conveniently as a natural blue colorant for food products. In this study, the identification of anthocyanin compounds in butterfly pea flowers was performed by UPLC coupled with a UV and Mass spectrometer instrument. Positive and negative ion electrospray MS/MS chromatograms and spectra of the anthocyanin compounds were determined. By analyzing the chromatograms and spectra for each ion, five anthocyanins were identified in the butterfly pea flower extract; these were delphinidin-3-(6”‐p-coumaroyl)-rutinoside, cyanidin 3-(6”-p-coumaroyl)-rutinoside, delphinidin-3-(p-coumaroyl) glucose in both cis- and trans- isomers, cyanidin-3-(p-coumaroyl-glucoside) and delphinidin-3-pyranoside. Additionally, based on their intensity, it was determined that cyanidin-3-(p-coumaroyl-glucoside) was the most abundant anthocyanin, followed by cyanidin 3-(6”-p-coumaroyl)-rutinoside, delphinidin-3-(p-coumaroyl-glucoside), delphinidin-3-(6”-p-coumaroyl)-rutinoside and delphinidin-3-pyranoside. In this study, cyanidin derivatives were discovered in butterfly pea flower extract, where these compounds had not been detected in previous studies.

New sterically hindered bis-catechol, bis- o -quinone and its bis-triphenylantimony(v) bis-catecholate. 3,5-Di- tert -butyl-6-methoxymethylcatechol as alkylating agent

2018 ◽  
Vol 28 (1) ◽  
pp. 76-78 ◽  
Author(s):  
Maxim V. Arsenyev ◽  
Tatyana V. Astafeva ◽  
Evgeny V. Baranov ◽  
Andrey I. Poddelsky ◽  
Sergey A. Chesnokov
Keyword(s):  
Alkylating Agent ◽  
Tert Butyl ◽  
Sterically Hindered

Unveiling the coexistence of cis- and trans-isomers in the hydrolysis of ZrO2: A coupled DFT and high-resolution photoelectron spectroscopy study

2020 ◽  
Vol 153 (24) ◽  
pp. 244308
Author(s):  
Ali Abou Taka ◽  
Mark C. Babin ◽  
Xianghai Sheng ◽  
Jessalyn A. DeVine ◽  
Daniel M. Neumark ◽  
...  
Keyword(s):  
High Resolution ◽  
Photoelectron Spectroscopy ◽  
Spectroscopy Study ◽  
Trans Isomers ◽  
Cis And Trans Isomers ◽  
Cis And Trans ◽  
Hydrolysis Of
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