267. Oxidation by persulphate. Part II. Oxidation effects with a methyl group and some substituted methyl groups on a benzene nucleus

1960 ◽  
pp. 1332 ◽  
Author(s):  
R. G. R. Bacon ◽  
J. R. Doggart
Keyword(s):  
Methyl Groups ◽  
Benzene Nucleus ◽  
Methyl Group

Net charges and valence AO's in the methylamines; the hydrogen basis set and the properties of nitrogen

1985 ◽  
Vol 63 (7) ◽  
pp. 1487-1491 ◽  
Author(s):  
Giuseppe Del Re ◽  
Sándor Fliszár ◽  
Michel Comeau ◽  
Claude Mijoule
Keyword(s):  
Basis Set ◽  
Basis Sets ◽  
Methyl Groups ◽  
Extended Form ◽  
Amine Nitrogen ◽  
Methyl Group ◽  
Net Charges ◽  
Extended Basis

Net charges and valence AO's for ammonia, methylamine, dimethylamine, and trimethylamine were calculated using extended basis sets. Superposition effects, evaluated by replacing Pople's standard 6-31G* basis by an extended form in which the basis of the ammonia H atoms and of the methyl groups of trimethylamine are retained in the treatment of each molecule, indicate that the quality of the treatment of amine nitrogen atoms is strongly dependent on the number of methyl groups. A new, augmented basis is proposed for the hydrogens, which appears to be reasonably well balanced: comparison with familiar (e.g., 6-31G*) calculations illustrates in what manner the treatment of nitrogen is worsened when even just one methyl group is replaced by hydrogen unless the impoverishment of the basis is suitably taken care of.

The Rates and Products of Addition of 4-Chlorobenzenesulfenyl Chloride to a Series of Side Chain Methyl Substituted Styrenes

1974 ◽  
Vol 52 (9) ◽  
pp. 1807-1812 ◽  
Author(s):  
George H. Schmid ◽  
Dennis G. Garratt
Keyword(s):  
Steric Hindrance ◽  
Side Chain ◽  
Methyl Groups ◽  
Methyl Group

The rates of addition and the product compositions have been determined for the addition of 4-chlorobenzenesulfenyl chloride to a series of seven side chain methyl substituted styrenes in 1,1,2,2-tetrachloroethane at 25°. Unlike the addition to the corresponding series of methylated ethylenes, the effect of the methyl groups is not cumulative. The effect of the methyl groups depends upon whether or not the β-methyl group is cis to the phenyl. When it is cis, the rate of addition is decreased compared to styrene and substitution of additional methyl groups has only a small effect on the rate of addition. In compounds lacking a cis-β-methyl group the rate of addition more closely resembles that for addition to the methylated ethylenes. Steric hindrance between the cis-methyl and phenyl groups is believed to be the cause of this difference in behavior between the ethylene and styrene series.

Transition metal-free C(sp3)–H bond coupling among three methyl groups

2017 ◽  
Vol 53 (38) ◽  
pp. 5346-5349 ◽  
Author(s):  
Yufeng Liu ◽  
Xi Zhan ◽  
Pengyi Ji ◽  
Jingwen Xu ◽  
Qiang Liu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Methyl Groups ◽  
Methyl Ketones ◽  
Reaction Conditions ◽  
Methyl Group ◽  
Metal Free

A coupling of multiple C(sp3)–H bonds of the methyl group in methyl ketones with dimethyl sulfoxides was developed under transition metal-free reaction conditions.

scholarly journals Modulation of Methyl Group Metabolism by Streptozotocin-induced Diabetes and All-trans-retinoic Acid

2004 ◽  
Vol 279 (44) ◽  
pp. 45708-45712 ◽  
Author(s):  
Kristin M. Nieman ◽  
Matthew J. Rowling ◽  
Timothy A. Garrow ◽  
Kevin L. Schalinske
Keyword(s):  
Retinoic Acid ◽  
Diabetic Rats ◽  
Significant Decline ◽  
Methionine Synthase ◽  
Methyl Groups ◽  
Culture Studies ◽  
Methyl Group ◽  
Trans Retinoic Acid ◽  
All Trans Retinoic Acid ◽  
Streptozotocin Induced Diabetes

The hepatic enzyme glycineN-methyltransferase (GNMT) plays a major role in the control of methyl group and homocysteine metabolism. Because disruption of these vital pathways is associated with numerous pathologies, understanding GNMT control is important for evaluating methyl group regulation. Recently, gluconeogenic conditions have been shown to modulate homocysteine metabolism and treatment with glucocorticoids and/or all-trans-retinoic acid (RA)-induced active GNMT protein, thereby leading to methyl group loss. This study was conducted to determine the effect of diabetes, alone and in combination with RA, on GNMT regulation. Diabetes and RA increased GNMT activity 87 and 148%, respectively. Moreover, the induction of GNMT activity by diabetes and RA was reflected in its abundance. Cell culture studies demonstrated that pretreatment with insulin prevented GNMT induction by both RA and dexamethasone. There was a significant decline in homocysteine concentrations in diabetic rats, owing in part to a 38% increase in the abundance of the transsulfuration enzyme cystathionine β-synthase; treatment of diabetic rats with RA prevented cystathionine β-synthase induction. A diabetic state also increased the activity of the folate-independent homocysteine remethylation enzyme betaine-homocysteineS-methyltransferase, whereas the activity of the folate-dependent enzyme methionine synthase was diminished 52%. In contrast, RA treatment attenuated the streptozotocin-mediated increase in betaine-homocysteineS-methyltransferase, whereas methionine synthase activity remained diminished. These results indicate that both a diabetic condition and RA treatment have marked effects on the metabolism of methyl groups and homocysteine, a finding that may have significant implications for diabetics and their potential sensitivity to retinoids.

THE ANAEROBIC DISSIMILATION OF D-GLUCOSE-1-C14, D-ARABINOSE-1-C14, AND L-ARABINOSE-1-C14 BY AEROBACTER AEROGENES

1954 ◽  
Vol 32 (1) ◽  
pp. 147-153 ◽  
Author(s):  
A. C. Neish ◽  
F. J. Simpson
Keyword(s):  
Carbon Dioxide ◽  
Acetic Acid ◽  
Lactic Acid ◽  
Carboxyl Groups ◽  
Methyl Groups ◽  
Carboxyl Group ◽  
Complete Conversion ◽  
Aerobacter Aerogenes ◽  
Methyl Group ◽  
Ethanol Acetic Acid

D-Glucose-1-C14, D-arabinose-1-C14, and L-arabinose-1-C14 were dissimilated anaerobically by Aerobacter aerogenes. The major products (2,3-butanediol, ethanol, acetic acid, lactic acid, formic acid, and carbon dioxide) were isolated and the location of C14 determined. The products from glucose were all labeled, mainly in the methyl groups, in agreement with the hypothesis that they were derived from methyl-labeled pyruvate formed by the reactions of the classical Embden–Meyerhof scheme for glycolysis. The products from both pentoses appeared to have been formed from pyruvate labeled in both the methyl and carboxyl groups with twice as much C14 in the methyl group as in the carboxyl group. This result may be explained quantitatively by a hypothesis assuming complete conversion of pentose to triose via a heptulose.

scholarly journals Effect of post-ruminal guanidinoacetic acid supplementation on creatine synthesis and plasma homocysteine concentrations in cattle

2020 ◽  
Vol 98 (3) ◽  
Author(s):  
Mehrnaz Ardalan ◽  
Erick D Batista ◽  
Evan C Titgemeyer
Keyword(s):  
Plasma Concentrations ◽  
High Energy ◽  
Plasma Homocysteine ◽  
Methyl Groups ◽  
Methyl Group ◽  
Guanidinoacetic Acid ◽  
Randomized Design ◽  
Entire Experiment ◽  
Main Plot ◽  
Plasma Arginine

Abstract Creatine stores high-energy phosphate bonds in muscle, which is critical for muscle activity. In animals, creatine is synthesized in the liver from guanidinoacetic acid (GAA) with methylation by S-adenosylmethionine. Because methyl groups are used for the conversion of GAA to creatine, methyl group deficiency may occur as a result of GAA supplementation. With this study, the metabolic responses of cattle to post-ruminal supplementation of GAA were evaluated with and without methionine (Met) supplementation as a source of methyl groups. Six ruminally cannulated Holstein heifers (520 kg) were used in a split-plot design with treatments arranged as a 2 × 5 factorial. The main plot treatments were 0 or 12 g/d of l-Met arranged in a completely randomized design; three heifers received each main plot treatment throughout the entire experiment. Subplot treatments were 0, 10, 20, 30, and 40 g/d of GAA, with GAA treatments provided in sequence from lowest to highest over five 6-d periods. Treatments were infused continuously to the abomasum. Heifers were limit-fed twice daily a diet consisting of (dry matter basis) 5.3 kg/d rolled corn, 3.6 kg/d alfalfa hay, and 50 g/d trace-mineralized salt. Plasma Met increased (P < 0.01) when Met was supplemented, but it was not affected by supplemental GAA. Supplementing GAA linearly increased plasma arginine (% of total amino acids) and plasma concentrations of GAA and creatinine (P < 0.001). Plasma creatine was increased at all levels of GAA except when 40 g/d of GAA was supplemented with no Met (GAA-quadratic × Met, P = 0.07). Plasma homocysteine was not affected by GAA supplementation when heifers received 12 g/d Met, but it was increased when 30 or 40 g/d of GAA was supplemented without Met (GAA-linear × Met, P = 0.003); increases were modest and did not suggest a dangerous hyperhomocysteinemia. Urinary concentrations of GAA and creatine were increased by all levels of GAA when 12 g/d Met was supplemented; increasing GAA supplementation up to 30 g/d without Met increased urinary GAA and creatine concentrations, but 40 g/d GAA did not affect urine concentrations of GAA and creatine when no Met was supplemented. Overall, post-ruminal GAA supplementation increased creatine supply to cattle. A methyl group deficiency, demonstrated by modest increases in plasma homocysteine, became apparent when 30 or 40 g/d of GAA was supplemented, but it was ameliorated by 12 g/d Met.

The effect of equi-molar dietary betaine and choline addition on performance and carcass quality of pigs

2001 ◽  
Vol 2001 ◽  
pp. 7-7
Author(s):  
H. Siljander-Rasi ◽  
K. Tiihonen ◽  
S. Peuranen ◽  
P.H. Simmins
Keyword(s):  
Diet Composition ◽  
Methyl Groups ◽  
Methyl Group ◽  
Feeding Level ◽  
Animal Feeding ◽  
Improved Performance ◽  
Pig Performance ◽  
Dietary Choline ◽  
Glycine Molecule

Betaine has three chemically reactive methyl groups attached to the nitrogen atom of the glycine molecule. Therefore, it can be used as a methyl group donor partially to replace methionine in poultry and pig diets. Recent work also suggests that betaine has an energy sparing role by reducing maintenance requirement of the pig (Schrama and Gerrits, 2000). Betaine has improved performance and carcass leanness in some studies but the results are variable and seem to depend on age and sex of the animal, feeding level and diet composition.Choline can also be used as methyl donor in animal feeds. In poultry, methyl groups are available after the conversion to betaine in the liver. However, dietary betaine is twice as efficient as the equi-molar dietary choline for increasing liver betaine levels in broiler chick (Saarinen et al., 2000). The aim of this study was to compare the response of pigs fed equi-molar betaine and choline in terms of pig performance and carcass characteristics.

Molecular Motion in Solid Tetrapropylammonium Bromide and Iodide

1992 ◽  
Vol 47 (11) ◽  
pp. 1115-1118 ◽  
Author(s):  
S. Lewicki ◽  
B. Szafranska ◽  
Z. Pajak
Keyword(s):  
Molecular Motion ◽  
Solid Phase ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Methyl Groups ◽  
Methyl Group ◽  
Spin Lattice ◽  
Tetrapropylammonium Bromide ◽  
Solid Phase Transition

Abstract The proton NMR second moment and spin-lattice relaxation time for tetrapropylammonium bromide and iodide have been measured over a wide temperature range. A solid-solid phase transition related to the onset of cation tumbling was found for both salts and confirmed by DTA. In the low temperature phases methyl group reorientation was evidenced. For iodide a dynamic nonequivalence of the methyl groups and the onset of ethyl groups motion was also discovered

Isomerizations akin to the Dimroth rearrangement. IV. Formation of simple s-Triazolo[1,5-c]pyrimidines via their [4,3-c] isomers

1978 ◽  
Vol 31 (11) ◽  
pp. 2505 ◽  
Author(s):  
DJ Brown ◽  
T Nagamatsu
Keyword(s):  
Acetic Acid ◽  
Glacial Acetic Acid ◽  
Methyl Groups ◽  
Dimroth Rearrangement ◽  
Methyl Group ◽  
Alkyl Groups ◽  
Ring Fission

Pyrimidin-4-ylhydrazines and simple orthoesters are used in combination (1) to give N-ethoxyalkyl-idene-N'-pyrimidinylhydrazines (2) and thence s-triazolo[4,3-c]pyrimidine (3a) and its 3-, 5-, 7- or 8-alkylated derivatives (3b-s). In glacial acetic acid, these undergo rearrangement into the corresponding s-triazolo[1,5-c]pyrimidines (5) via the acylaminoalkenyltriazoles (4); in aqueous buffers, these reactions stop at the triazoles (4) except in the presence of a 7-methyl group which stimulates completion of the sequence. The ring-fission step, (3) → (4), is retarded markedly by 5- and/or 8-methyl groups but accelerated slightly by 3- and/or 7-alkyl groups; the slower ring-fission of triazolo[1,5-c]-pyrimidines (5) to the same triazoles (4) is retarded by 2-, 5- or 8-alkylation and precluded totally by a 7-methyl group. The recorded u.v. and N.M.R. spectra afford a ready means of distinguishing between the systems (3)-(5).

Absolute stereochemistry of calopiptin

1968 ◽  
Vol 21 (8) ◽  
pp. 2095 ◽  
Author(s):  
JB Mc Alpine ◽  
NV Riggs ◽  
PG Gordon
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
High Resolution Mass Spectrometry ◽  
The Other ◽  
Methyl Groups ◽  
Lower Field ◽  
Methyl Group ◽  
Low Field ◽  
Absolute Stereochemistry ◽  
Resolution Mass

The α,α?-diaryl-β,β-dimethyltetrahydrofurenoid lignan, calopiptin, from Piptocalyx moorei has been converted by demethylenation and methylation into veraguensin, now also isolated from Trimenia papuana (both species, family Trimeniaceae). Ozonolysis yields (-)-2,3-dimethylsuocinic acid which establishes the absolute trans configuration of the methyl groups. The benzylic proton giving a signal at low field from the other in the p.m.r, spectrum is assigned as trans to the adjacent methyl group by shielding and spin-decoupling arguments. The signal moves to even lower field on nitration of one of the aryl groups, identified as 3,4-dimethoxyphenyl by competitive nitration experiments and high-resolution mass spectrometry. Calopiptin is 2R-(3,4-dimethoxyphenyl)-3S,4S-dimethyl-5S-(3,4-methylenedioxyphenyl)tetrahydrofuran.

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