Molybdenum Imido Alkylidene Complexes Containing Biphen Ligands that Have Silyl Groups Attached through the 6 and 6‘ Methyl Group Carbon Atoms

2001 ◽  
Vol 20 (22) ◽  
pp. 4705-4712 ◽  
Author(s):  
Kai C. Hultzsch ◽  
Peter J. Bonitatebus, ◽  
Jesper Jernelius ◽  
Richard R. Schrock ◽  
Amir H. Hoveyda
Keyword(s):  
Methyl Group ◽  
Silyl Groups ◽  
Group Carbon ◽  
Alkylidene Complexes

The Substituent Effect of the Methyl Group. Carbon 1s Ionization Energies, Proton Affinities, and Reactivities of the Methylbenzenes

2007 ◽  
Vol 72 (15) ◽  
pp. 5715-5723 ◽  
Author(s):  
Velaug Myrseth ◽  
Knut J. Børve ◽  
T. Darrah Thomas
Keyword(s):  
Substituent Effect ◽  
Proton Affinities ◽  
Ionization Energies ◽  
Methyl Group ◽  
Group Carbon

Position-specific isotope analysis of the methyl group carbon in methylcobalamin for the investigation of biomethylation processes

2013 ◽  
Vol 405 (9) ◽  
pp. 2833-2841 ◽  
Author(s):  
Oliver Wuerfel ◽  
Markus Greule ◽  
Frank Keppler ◽  
Maik A. Jochmann ◽  
Torsten C. Schmidt
Keyword(s):  
Isotope Analysis ◽  
Methyl Group ◽  
Group Carbon

Silicon-29 and carbon-13 NMR spectra of model alkylsilanes of the type (CH3)3-nXnSi(CH2)mH

1979 ◽  
Vol 44 (3) ◽  
pp. 854-865 ◽  
Author(s):  
Jan Schraml ◽  
Václav Chvalovský ◽  
Märt Mägi ◽  
Endel Lippmaa
Keyword(s):  
Chain Length ◽  
Silicon Atom ◽  
Alkyl Chain ◽  
Chemical Shifts ◽  
Alkyl Chain Length ◽  
Minor Role ◽  
Total Charge ◽  
Methyl Group ◽  
Silyl Groups ◽  
A Minor

29Si and 13C NMR chemical shifts are presented for the compounds of the type (CH3)3-nXnSi(CH2)mH with various combinations of substituent X (X = C2H5, OC2H5, OC(O)CH3, and Cl), their number n, and alkyl chain length m (m = 1-5). Silicon-29 chemical shifts are shown to follow general trends of the dependence on the total charge or on the number and nature of the substituents on the silicon atom, the alkyl chain length playing only a minor role. It is demonstrated that the silicon upfield shift due to a γ-methyl group varies between is -0.9 and -1.8 ppm in the compounds, the silicon atom of which bears only one secondary carbon atom. The 13C chemical shifts also follow the general dependence on the total charge. In the trimethylsilyl derivatives methylene carbon chemical shifts correlate with the corresponding shifts in carbon analogues and with those in hydrocarbons in which the trimethylsilyl group is replaced by a methyl group. For the short alkyls (m = 1-3) the substituent chemical shifts of various silyl groups depend on the alkyl chain length, α and β effects seem to depend on the number and nature of the substituents on the silicon atom.

scholarly journals ISOLATION AND IDENTIFICATION OF TERPENOID COMPOUNDS FROM n-HEXANA EXTRACT OF PERMOT PLANT BRACTS (Passiflora foetida L)

2017 ◽  
Vol 11 (2) ◽  
pp. 80
Author(s):  
Maria Dewi Astuti ◽  
Tuti Sriwinarti ◽  
Kamilia Mustikasari
Keyword(s):  
Double Bond ◽  
1H Nmr ◽  
Nmr Spectra ◽  
Ester Group ◽  
Hexane Extract ◽  
Isolation And Identification ◽  
Methyl Group ◽  
Vacuum Liquid Chromatography ◽  
Passiflora Foetida ◽  
Group Carbon

Isolation and identification of terpenoids compounds from n-hexane extract of permot bracts plants (Passiflora foetida L.) has been done. Crude powder of the bracts permot plants were macerated with n-hexane. Fractionated of n-hexane extract on a vacuum liquid chromatography to afford three fractions (A, B and C). Purification of fraction B with TLC preparative to afford isolate B1 and B2.. A compound of spectra UV-Vis B1 indicating the presence of conjugation of double bond (C=C), furthermore the IR spectra showed vibration for - OH group, C=O of the ester group, C-O group, and methyl group (-CH3) in position gem dimethyl. 1H-NMR spectra showed the signal from methoxy group (OCH3), olefin protons (-CH=CH-), protons in carbon to the oxygenation (C-OH), two units gem dimethyl, and three methyl group (-CH3). 13C-NMR spectra showed thesignal from carbon aliphatic group, carbon carbonil (C=O) of the ester group, double bond carbon (C=C), and carbon to the oxygenation (C-OCH3 and C-OH)). Based on the analysis of UV-Vis, IR, 1H-NMR, and 1H-NMR spectrocopies data, isolate B1 is suggested from terpenoids type triterpenoids pentacyclic that conjugation of double bond and ester group.Keywords: Terpenoids, triterpenoids pentacyclic, permot (Passiflora foetida L.), and n-hexane extract.

Use of [13C-methyl]Tropinone to follow the fate of the methyl group during calystegine formation in root cultures of Solanum dulcamara (Solanaceae)

Planta Medica ◽  
2008 ◽  
Vol 74 (09) ◽  
Author(s):  
TA Bartholomeusz ◽  
R Molinié ◽  
A Roscher ◽  
AC Freydank ◽  
B Dräger ◽  
...  
Keyword(s):  
Root Cultures ◽  
Solanum Dulcamara ◽  
Methyl Group

STEROIDSTRUKTUR UND LEBERTOXIZITÄT

1967 ◽  
Vol 54 (1) ◽  
pp. 73-84 ◽  
Author(s):  
H. L. Krüskemper ◽  
G. Noell
Keyword(s):  
Alkaline Phosphatase ◽  
Liver Function ◽  
Blood Coagulation ◽  
Electrophoretic Pattern ◽  
Coagulation Factors ◽  
Blood Coagulation Factors ◽  
Methyl Group ◽  
Liver Functions ◽  
Male Subjects ◽  
Androstane Derivatives

ABSTRACT In male subjects investigations have been carried out regarding the effect of C1- and C17-methylated androstane derivatives (20 mg per day, orally, two weeks) on liver functions (parameters: activities of GPT, GOT, alkaline phosphatase and cholinesterase in serum; electrophoretic pattern; blood coagulation factors V, VII, X and prothrombin; BSP-retention). In addition to the well known hepatotropic action of 17α-alkylated C-19-steroids a quasi-axial 1α-methyl configuration (in 1α-methylandrost-2-en-17β-ol) definitely increased BSP-retention and several coagulation factors. These steroid effects decreased gradually when a methyl group was introduced in C1 equatorially (1-methylandrost-1-en-17β-ol-3-one) or quasi-equatorially (1β-methylandrost-2-en-17β-ol), the latter compound completely lacking from any influence on parameters of liver function under investigation.

Methyl-Group Metabolism and the Response of Colorectal Cancer to 5-Fluorouracil

2006 ◽  
Vol 12 (1-2) ◽  
pp. 115-126 ◽  
Author(s):  
Barry Iacopetta
Keyword(s):  
Colorectal Cancer ◽  
Methyl Group

A Reinvestigation of the Deceptively Simple Reaction of Toluene with ●OH, and the Fate of the Benzyl Radical. I. a Combined Thermodynamic and Kinetic Study on the Competition Between ●OH Addition and Hydrogen Abstraction Reactions.

2019 ◽  
Author(s):  
Zoi Salta ◽  
Agnie M. Kosmas ◽  
Marc E. Segovia ◽  
Martina Kieninger ◽  
Oscar Ventura ◽  
...  
Keyword(s):  
Density Functional ◽  
Room Temperature ◽  
Hydrogen Abstraction ◽  
Reaction Rates ◽  
Composite Model ◽  
Alternative Mechanism ◽  
Radical Intermediate ◽  
Experimental Conditions ◽  
Methyl Group ◽  
Benzyl Radical

This work reports density functional and composite model chemistry calculations performed on the reactions of toluene with the hydroxyl radical. Both experimentally observed H-abstraction from the methyl group and possible additions to the phenyl ring were investigated. Reaction enthalpies and heights of the barriers suggest that H-abstraction is more favorable than ●OH addition to the ring. The calculated reaction rates at room temperature and the radical-intermediate product fractions support this view. This is somehow contradictory with the fact that, under most experimental conditions, cresols are observed in a larger concentration than benzaldehyde. Since the accepted mechanism for benzaldehyde formation involves H-abstraction, a contradiction arises that begs for an explanation. In this first part of our work we give the evidences that support the preference of hydrogen abstraction over ●OH addition and suggest an alternative mechanism which shows that cresols can actually arise also from the former reaction and not only from the latter.

A Reinvestigation of the Deceptively Simple Reaction of Toluene with ●OH, and the Fate of the Benzyl Radical. I. a Combined Thermodynamic and Kinetic Study on the Competition Between ●OH Addition and Hydrogen Abstraction Reactions.

2019 ◽  
Author(s):  
Zoi Salta ◽  
Agnie M. Kosmas ◽  
Marc E. Segovia ◽  
Martina Kieninger ◽  
Oscar Ventura ◽  
...  
Keyword(s):  
Density Functional ◽  
Room Temperature ◽  
Hydrogen Abstraction ◽  
Reaction Rates ◽  
Composite Model ◽  
Alternative Mechanism ◽  
Radical Intermediate ◽  
Experimental Conditions ◽  
Methyl Group ◽  
Benzyl Radical

This work reports density functional and composite model chemistry calculations performed on the reactions of toluene with the hydroxyl radical. Both experimentally observed H-abstraction from the methyl group and possible additions to the phenyl ring were investigated. Reaction enthalpies and heights of the barriers suggest that H-abstraction is more favorable than ●OH addition to the ring. The calculated reaction rates at room temperature and the radical-intermediate product fractions support this view. This is somehow contradictory with the fact that, under most experimental conditions, cresols are observed in a larger concentration than benzaldehyde. Since the accepted mechanism for benzaldehyde formation involves H-abstraction, a contradiction arises that begs for an explanation. In this first part of our work we give the evidences that support the preference of hydrogen abstraction over ●OH addition and suggest an alternative mechanism which shows that cresols can actually arise also from the former reaction and not only from the latter.

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