METHYLATION OF SUGAR DITHIOACETALS: V. D-MANNOSE DIETHYL DITHIOACETAL

1963 ◽  
Vol 41 (10) ◽  
pp. 2500-2503 ◽  
Author(s):  
G. G. S. Dutton ◽  
Y. Tanaka
Keyword(s):  
Methyl Iodide ◽  
Silver Oxide ◽  
The Other ◽  
Partial Methylation

Partial methylation of D-mannose diethyl dithioacetal in tetrahydrofuran with methyl iodide and silver oxide yielded 2-, 3-, and 6-O-methyl-D-mannose in the ratio of 12:1:1, respectively. The major component, 2-O-methyl-D-mannose, was characterized as the phenyl-hydrazone and the other isomers identified by electrophoresis. The Mg values of these mono-O-methyl ethers were recorded.

METHYLATION OF SUGAR DITHIOACETALS: IV. D-XYLOSE DIETHYL DITHIOACETAL

1962 ◽  
Vol 40 (10) ◽  
pp. 1899-1902 ◽  
Author(s):  
G. G. S. Dutton ◽  
Y. Tanaka
Keyword(s):  
Methyl Iodide ◽  
Methyl Ether ◽  
Silver Oxide ◽  
Partial Methylation ◽  
Tetrahydrofuran Solution

Partial methylation of D-xylose diethyl dithioacetal in tetrahydrofuran with methyl iodide and silver oxide yielded 2-, 3-, and 5-O-methyl-D-xyloses in the ratio of 20:10:1. The poly-O-methylated components were not examined. The 2-O-methyl-D-xylose was identified as the crystalline sugar and the 3-O-methyl ether as the phenylosazone and p-bromophenylosazone. An alternative preparation of the dithioacetal in tetrahydrofuran solution is described.

scholarly journals The preparation of some fused isothiazole derivatives

1985 ◽  
Vol 63 (4) ◽  
pp. 882-886 ◽  
Author(s):  
David M. McKinnon ◽  
K. Ann Duncan ◽  
Aileen M. McKinnon ◽  
Perry A. Spevack
Keyword(s):  
Methyl Iodide ◽  
The Other ◽  
Methylation Product

The treatment of di(2-amino-5-methylphenyl)methane with N-sulfinylmethanesulfonamide gives two materials, 3-(2-amino-5-methylphenyl)-5-methyl-2,1-benzisothiazole and what appears to be its tautomer, a 2,1-benzisothiazolo[2,3-b]-2,1-benzisothiazole derivative. Reaction of the former with methyl iodide gives mono-, di-, and trimethyl derivatives. The second of these also possesses the symmetrical 2,1-benzisothiazolo[2,3-b]-2,1-benztsothiazole structure. The structure of the other methylation product and of the acetylation products are discussed. Some 1,2-dithiol-3-ylidene-2-pyridylmethanes were made by condensation of 3-alkylthio-1,2-dithiolium salts with methyl 2-pyridylacetate. These demonstrate little sulphur–nitrogen interaction. 3-Methylthio-4-phenyl-1,2-dithiolium iodide reacts anomalously with methyl 2-pyridylacetate to form a quinolizinethione. 1,2-Benzisothiazolo[2,3-a]pyridintum triiodide was made by iodine oxidation of 2-(2-mercaptophenylpyridine).

METHYLATION OF SUGAR MERCAPTALS: II. L-ARABINOSE DIETHYL MERCAPTAL

1961 ◽  
Vol 39 (9) ◽  
pp. 1797-1800 ◽  
Author(s):  
G. G. S. Dutton ◽  
Y. Tanaka
Keyword(s):  
Methyl Iodide ◽  
Silver Oxide

Methylation of L-arabinose diethyl mercaptal in tetrahydrofuran with methyl iodide and silver oxide yielded mainly 2-O-methyl-L-arabinose and a trace of 5-O-methyl-L-arabinose. The identity of the major component was inferred by its behavior on electrophoresis and confirmed by the preparation of the crystalline amide. The polymethylated components were not examined. 2-O-Methyl-L-arabono-γ-lactone, previously known as a sirup, has now been obtained crystalline.

STUDIES OF REACTIONS RELATING TO CARBOHYDRATES AND POLYSACCHARIDES.: XXVIII. THE STRUCTURE OF ISOPROPYLIDENE GLYCEROL

1930 ◽  
Vol 2 (3) ◽  
pp. 214-217 ◽  
Author(s):  
Harold Hibbert ◽  
J. G. Morazain
Keyword(s):  
Methyl Iodide ◽  
Methyl Ether ◽  
Copper Sulphate ◽  
Silver Oxide ◽  
Condensation Product ◽  
Neutral Medium ◽  
Physico Chemical ◽  
Isopropylidene Glycerol

Isopropylidene glycerol, prepared in neutral medium by the action of anhydrous copper sulphate as condensing agent, was methylated with silver oxide and methyl iodide; the product yielded only glycerol α-methyl ether on hydrolysis, thus proving the absence of any six-membered ketal in the condensation product of glycerol and acetone.The properties of both glycerol α- and β-methyl ethers have been carefully redetermined.A table of the isomeric acetals and ketals summarising their physico-chemical constants is given, in view of their usefulness as "type compounds" in investigations relating to fats, carbohydrates and polysaccharides.

N-Methylamino acids in peptide synthesis. VII. Studies on the enantiomeric purity of N-methylamino acids prepared by various procedures

1977 ◽  
Vol 55 (5) ◽  
pp. 916-921 ◽  
Author(s):  
S. T. Cheung ◽  
N. Leo Benoiton
Keyword(s):  
Amino Acid ◽  
Methyl Iodide ◽  
Peptide Synthesis ◽  
Liquid Ammonia ◽  
Silver Oxide ◽  
Sodium Hydride ◽  
Enantiomeric Purity ◽  
Amino Acid Analyzer ◽  
Pure Compounds ◽  
Optically Pure

The enantiomeric purity of N-methylamino acids and their derivatives obtained by various procedures has been examined by analysis with an amino-acid analyzer of the diastereomeric lysyl dipeptides formed by coupling them with a lysyl derivative. N-Benzyloxycarbonyl, and N-tert-butyloxycarbonyl,N-methylamino acids obtained by methylation of the parent derivative using sodium hydride and methyl iodide, and N-methylamino acids obtained by methylation of the p-toluenesulfonylamino acid followed by treatment with sodium in liquid ammonia, are optically pure. Compounds obtained by other procedures which include reductive alkylations or the use of silver oxide – methyl iodide are generally not optically pure.

Partial methylation of methyl α-D- and β-D-threofuranoside

1990 ◽  
Vol 55 (7) ◽  
pp. 1777-1782 ◽  
Author(s):  
Jiří Jarý ◽  
Miroslav Marek ◽  
Ivan Raich
Keyword(s):  
Sodium Hydroxide ◽  
Methyl Iodide ◽  
Rate Constants ◽  
Relative Rate ◽  
Hydroxyl Groups ◽  
Partial Methylation ◽  
Methylation Rate ◽  
Consecutive Reactions ◽  
Relative Rate Constants ◽  
The Individual

The methylation rate of hydroxyl groups of the title glycosides I and II has been studied in their reaction with methyl iodide and sodium hydroxide in acetonitrile. From the relative rate constants determined for the side and consecutive reactions taking place the differences in methylation rate of the individual hydroxyl groups have been deduced and are discussed from the standpoint of possible steric and polar effects.

Thiazoloisoquinolines. III. Structure and methylation of 2-hydroxythiazolo[4,5-c]- and -[5,4-c]isoquinolines

1968 ◽  
Vol 46 (5) ◽  
pp. 691-694 ◽  
Author(s):  
Catherine E. Hall ◽  
Alfred Taurins
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Methyl Iodide ◽  
Dimethyl Sulfate ◽  
The Other ◽  
Thiazole Ring ◽  
Spectral Evidence ◽  
Other Hand ◽  
Methylating Agents ◽  
Nuclear Magnetic

2-Hydroxythiazolo[4,5-c]isoquinoline (1) and 2-hydroxythiazolo[5,4-c]isoquinoline (2) were both found to exist predominantly in the lactam form (1b and 2b respectively) from infrared, nuclear magnetic resonance, and ultraviolet spectral evidence. Various methylating agents methylated compound 1 exclusively on the N-3 atom in the thiazole ring. Compound 2 on the other hand, gave a mixture of O-and N-3 methylated products with diazomethane and a mixture of N-1 and N-4 methylated products with either methyl iodide or dimethyl sulfate.

Rates of N-methylation of azoles with methyl iodide and dimethyl sulphate

1973 ◽  
Vol 26 (9) ◽  
pp. 1949 ◽  
Author(s):  
LW Deady
Keyword(s):  
Methyl Iodide ◽  
Dimethyl Sulphate ◽  
Inductive Effect ◽  
Reaction Rates ◽  
Dimethyl Sulphoxide ◽  
The Other

The rates of quaternization of various azoles and their benzo derivatives with dimethyl sulphate, and with methyl iodide in dimethyl sulphoxide, are reported. Reaction rates are controlled mainly by the inductive effect of the other hetero atom and there is a good correlation between rate of quaternization and basicity of the azole.

scholarly journals The contribution of oceanic methyl iodide to stratospheric iodine

2013 ◽  
Vol 13 (4) ◽  
pp. 11427-11471 ◽  
Author(s):  
S. Tegtmeier ◽  
K. Krüger ◽  
B. Quack ◽  
E. Atlas ◽  
D. R. Blake ◽  
...  
Keyword(s):  
Methyl Iodide ◽  
Transport Model ◽  
The Other ◽  
Simultaneous Occurrence ◽  
West Pacific ◽  
Tropical Regions ◽  
Convective Systems ◽  
Mixing Ratios ◽  
Tropical Tropopause ◽  
Cold Point

Abstract. We investigate the contribution of oceanic methyl iodide (CH3I) to the stratospheric iodine budget. Based on CH3I measurements during three tropical ship campaigns and the Lagrangian transport model FLEXPART we provide a detailed analysis of CH3I transport from the ocean surface to the cold point in the upper tropical tropopause layer (TTL). While average oceanic emissions differ by less than 50% from campaign to campaign, the measurements show much stronger variations within each campaign. A positive correlation between the oceanic CH3I emissions and the efficiency of CH3I troposphere–stratosphere transport has been identified for some cruise sections. The mechanism of strong horizontal surface winds triggering large emissions on the one hand and being associated with tropical convective systems, such as developing typhoons, on the other hand, could explain the identified correlations. As a result of the simultaneous occurrence of large CH3I emissions and strong vertical uplift, localized maximum mixing ratios of 0.6 ppt CH3I at the cold point have been determined for observed peak emissions during the SHIVA-Sonne campaign in the coastal West Pacific. The other two campaigns give considerable smaller maxima of 0.1 ppt CH3I for the TransBrom campaign in the open West Pacific and 0.03 ppt for emissions from the coastal East Atlantic during the DRIVE campaign. In order to assess the representativeness of the large local mixing ratios we use climatological emission scenarios to derive global upper air estimates of CH3I abundances. The model results are compared to available upper air measurements including data from the recent ATTREX and HIPPO2 aircraft campaigns. In the East Pacific region, the location of the available measurement campaigns in the upper TTL, the comparisons give a good agreement indicating that around 0.01 to 0.02 ppt of CH3I enter the stratosphere. However, other tropical regions, which are subject to stronger convective activity show larger CH3I entrainment, e.g., 0.08 ppt in the West Pacific. The strong variations in the geographical distribution of CH3I entrainment suggest that currently available upper air measurements are not representative of global estimates and further campaigns will be necessary in order to better understand the CH3I contribution to stratospheric iodine.

ipso Nitration. XXIII. Reactions of cyclohexadiene adducts from nitration of 4-ethyltoluene in acetic anhydride

1981 ◽  
Vol 59 (15) ◽  
pp. 2314-2327 ◽  
Author(s):  
Alfred Fischer ◽  
George N. Henderson
Keyword(s):  
Sulfuric Acid ◽  
Acetic Anhydride ◽  
Methyl Iodide ◽  
Methyl Ether ◽  
Potassium Hydroxide ◽  
Silver Oxide ◽  
Aluminum Hydride ◽  
Trifluoroacetic Anhydride ◽  
Aqueous Methanol

The diastereoisomers of 4-ethyl-1-methyl-4-nitrocyclohexa-2,5-dienyl acetate (1) and 1-ethyl-4-methyl-4-nitrocyclohexa-2,5-dienyl acetate (2) are stereospecifically reduced to the corresponding nitrocyclohexadienols with aluminum hydride. Each dienol is stereospecifically methylated to the corresponding methyl ether with methyl iodide, silver oxide, and potassium hydroxide. Acid-catalysed solvolysis of the acetates 1 and 2 results in the substitution of the acetate moiety by other nucleophiles and these reactions are not stereospecific. The products of rearomatization of dienyl acetates, dienols, and dienyl methyl ethers depend on the acidity and ionizing power of the solvents and are readily explained in terms of reactions involving a nitrocyclohexadienyl cation or acetoxy- (hydroxy-, methoxy-)cyclohexadienyl cation as key intermediates. In the 4-acetoxy-4-alkylcyclohexadienyl cation 1,2-migration of the acetoxyl group is more rapid than alkyl migration, but 1,2-alkyl migration is faster than migration of the hydroxyl or methoxyl groups in the corresponding cations. 1-Ethyl-4-methoxy-4-methylcyclohexa-2,5-dien-1-ol and 4-ethyl-3-nitrotoluene are significant minor products in the solvolysis of 1-ethyl-4-methyl-4-nitrocyclohexa-2,5-dien-1-ol in aqueous methanol. Nitration of p-ethyltoluene in the presence of sulfuric acid or in trifluoroacetic anhydride gives a mixture of 4-ethyl-2-nitro- and 4-ethyl-3-nitrotoluene in a 2:1 ratio.

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