Isotopic localization of the partially deuterated methyl group in solid methanol and methyl iodide

2017 ◽  
Vol 146 (17) ◽  
pp. 174501 ◽  
Author(s):  
Hal Suzuki ◽  
Akira Inaba
Keyword(s):  
Methyl Iodide ◽  
Methyl Group

Methanogenesis from Acetate by Methanosarcina barkeri: Catalysis of Acetate Formation from Methyl Iodide, CO2 , and H2 by the Enzyme System Involved

1987 ◽  
Vol 42 (4) ◽  
pp. 360-372 ◽  
Author(s):  
Kerstin Laufer ◽  
Bernhard Eikmanns ◽  
Ursula Frimmer ◽  
Rudolf K. Thauer
Keyword(s):  
Methyl Iodide ◽  
Condensation Reaction ◽  
Methyl Chloride ◽  
Methanosarcina Barkeri ◽  
Carboxyl Group ◽  
Atpase Inhibitor ◽  
Methyl Group ◽  
Proton Potential ◽  
Acetate Formation ◽  
Reducing Equivalents

Cell suspensions of Methanosarcina barkeri grown on acetate catalyze the formation of methane and CO2 from acetate as well as an isotopic exchange between the carboxyl group of acetate and CO2. Here we report that these cells also mediate the synthesis of acetate from methyl iodide, CO2, and reducing equivalents (H2 or CO), the methyl group of acetate being derived from methyl iodide and the carboxyl group from CO2. Methyl chloride and methyltosylate but not methanol can substitute for methyl iodide in this reaction. Acetate formation from methyl iodide, CO2, and reducing equivalents is coupled with the phosphorylation of ADP. Evidence is pres­ented that methyl iodide is incorporated into the methyl group of acetate via a methyl corrinoid intermediate (deduced from inhibition experiments with propyl iodide) and that CO2 is assimi­lated into the carboxyl group via a C1 intermediate which does not exchange with free formate or free CO. The effects of protonophores, of the proton-translocating ATPase inhibitor N.N′-di- cyclohexylcarbodiimide, and of arsenate on acetate formation are interpreted to indicate that the reduction of CO2 to the oxidation level of the carboxyl group of acetate requires the presence of an electrochemical proton potential and that acetyl-CoA or acetyl-phosphate rather than free acetate is the immediate product of the condensation reaction. These results are discussed with respect to the mechanism of methanogenesis from acetate.

Zur Koordinations-Isomerie (a-b-Isomerie) der Co-Alkyl-corrinoide

1969 ◽  
Vol 24 (5) ◽  
pp. 588-596 ◽  
Author(s):  
Wilhelm Friedrich ◽  
Johann Peter Nordmeyer
Keyword(s):  
Absorption Spectrum ◽  
Aqueous Medium ◽  
Methyl Iodide ◽  
Dimethyl Sulfate ◽  
Thermal Isomerization ◽  
Reaction Products ◽  
Acid Media ◽  
Methyl Group

Chromatography and electrophoresis of the reaction products from B12s and methyl iodide yield the known Co-methyl-cobalamin and a new light sensitive corrinoid compound. The latter is very probably Co-methyl-cobalamin a with the methyl group “down”. The absorption spectrum of this yellow corrinoid differs only slightly from that of Co-methyl-cobalamin in acid media and does not depend on pH at wavelengths higher than 300 nm. The new corrinoid is thermolabile and on heating at 95°C for several hours in O2-free aqueous medium changes nearly quantitatively to Comethyl-cobalamin. The last corrinoid, on the contrary, yields at 95 cC several per cents of Comethyl-cobalamin a. The reaction of B12s with dimethyl sulfate yields beyond the mentioned products Co-methyl-cobalamin Nm (yellow; the absorption spectrum does not depend on pH and is identical with that of Co-methyl-cobalamin in acid media) and B12Nm (both corrinoids have a methyl group on N-3 of the 5,6-dimethylbenzimidazole moiety). The thermal isomerization of both Co-methyl-cobalamins is in accord with the observed formation of Co-14CH3-cobinamide on heating of Co-14CH3-cobalamin with Co-CH3-cobinamide.

scholarly journals Benzazole derivatives, VI: Synthesis of some 2-styrylbenzimidazoles and their quaternization

2005 ◽  
Vol 11 (1) ◽  
pp. 19-24 ◽  
Author(s):  
Corina Cernatescu ◽  
Eugenia Comanita
Keyword(s):  
High Temperature ◽  
Benzene Ring ◽  
Methyl Iodide ◽  
1H Nmr ◽  
Aromatic Aldehydes ◽  
Spectral Measurements ◽  
Methyl Group ◽  
Alternative Method ◽  
Ethylene Bond

In this paper an alternative method for obtaining styrylbenzimidazolium iodides was described. Thus, some 1-methyl-2-styrylbenzimidazoles were synthesized by the condensation of 1,2-dimethylbenzimidazoles containing a mono- or di-substituted benzene ring (X = NO2, Br), at their reactive 2-methyl group with aromatic aldehydes by heating at high temperature. Some of the 2-styrylbenzimidazoles were proved to be able to convert into benzimidazolium quaternary iodides by treating them with methyl iodide in an autoclave. The structures of the 2-styrylbenzimidazoles and corresponding iodomethyl derivatives were investigated by IR and 1H-NMR spectral measurements. The obtained compounds are valuable due to their structures of polyenic dyes, with a photoexcitable ethylene bond.

Alkylation, metalation and ring contraction of tropiporphyrin

2020 ◽  
Vol 24 (01n03) ◽  
pp. 181-190
Author(s):  
Timothy D. Lash ◽  
John M. Rooney
Keyword(s):  
Methyl Iodide ◽  
Potassium Carbonate ◽  
Methyl Substituent ◽  
Ring Contraction ◽  
Methyl Group ◽  
Contrast Reaction

Tropiporphyrins are an intriguing class of carbaporphyrinoids that incorporate a cycloheptatriene subunit. Previous investigations have shown that this system acts as a trianionic ligand that can form stable silver(III) complexes. In this work, tropiporphyrin was reacted with excess methyl iodide and potassium carbonate in refluxing acetone to give an internally alkylated derivative. The reaction occurred regioselectively to introduce a methyl group onto the 24-position. Reaction with palladium(II) acetate afforded a palladium(II) complex that retained the [Formula: see text]-methyl substituent. In contrast, reaction of [Formula: see text]-unsubstituted tropiporphyrin with palladium(II) acetate gave two palladium(II) benziporphyrins, one of which possessed a formyl substituent. Although these organometallic derivatives were obtained in relatively low yields, the observation of unexpected ring contraction products demonstrates that the reactivity of the tropiporphyrin system deserves to be further investigated.

scholarly journals Fluorinated cyclohexanes: Synthesis of amine building blocks of the all-cis 2,3,5,6-tetrafluorocyclohexylamine motif

2017 ◽  
Vol 13 ◽  
pp. 728-733 ◽  
Author(s):  
Tetiana Bykova ◽  
Nawaf Al-Maharik ◽  
Alexandra M Z Slawin ◽  
David O'Hagan
Keyword(s):  
Methyl Iodide ◽  
Ring Opening ◽  
Building Blocks ◽  
Ring System ◽  
Cyclohexane Ring ◽  
Birch Reduction ◽  
Methyl Group ◽  
Ring Opening Reactions

This paper reports the synthesis of three amine stereoisomers 5a–c of the tetrafluorocyclohexyl ring system, as building blocks for discovery chemistry programmes. The synthesis starts from a Birch reduction of benzonitrile, followed by an in situ methyl iodide quench. The resultant 2,5-cyclohexadiene was progressed via double epoxidations and then hydrofluorination ring opening reactions. The resultant fluorohydrin moieties were then converted to different stereoisomers of the tetrafluorocyclohexyl ring system, and then reductive hydrogenation of the nitrile delivered three amine stereoisomers. It proved necessary to place a methyl group on the cyclohexane ring in order to stabilise the compound against subsequent HF elimination. The two all-cis tetrafluorocyclohexyl isomers 5a and 5b constitute facially polarized cyclohexane rings, with fluorines on the electronegative face and hydrogens on the electropositive face.

Alkaloids of the Australian Rutaceae: Lunasia quercifolia. II. The Nature of Lunasine

1959 ◽  
Vol 12 (3) ◽  
pp. 458 ◽  
Author(s):  
JR Price
Keyword(s):  
Oxygen Atom ◽  
Methyl Iodide ◽  
Principal Component ◽  
Alkyl Halides ◽  
Water Soluble ◽  
Methyl Group

The principal component of the mixture of water-soluble alkaloids of Lunasia quercifolia is shown to be the quaternary 4-methoxy-1-methylquinolinium structure IV corresponding to the 1-methyl-4-quinolone alkaloid lunacrine. The formation of IV from lunacrine and methyl iodide involves addition of the methyl group to the quinolone oxygen atom. It is suggested that this, as with the γ-pyrones, is the usual mode of reaction of 4-quinolone with alkyl halides. The properties of 4-methoxyquinolinium salts are discussed in relation to the conversion of furoquinoline alkaloids to the iso-alkaloids.

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.

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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