THE ALCOHOLYSIS OF TRIALKYLALKOXYSILANES: PART II. THE PREPARATION AND CHEMISTRY OF METHYL 2,3,4-TRI-O-TRI-METHYLSILYL-α-D-GLUCOPYRANOSIDE

1965 ◽  
Vol 43 (7) ◽  
pp. 2004-2011 ◽  
Author(s):  
D. T Hurst ◽  
A. G. McInnes
Keyword(s):  
Magnetic Resonance ◽  
Acetic Anhydride ◽  
Proton Magnetic Resonance ◽  
Benzoyl Chloride ◽  
Phenyl Isocyanate ◽  
High Yield ◽  
Aqueous Methanol ◽  
Trimethylsilyl Group ◽  
Acidic Catalysts ◽  
Derivatives Of

The trimethylsilyl group on the 6-position of methyl 2,3,4,6-tetra-O-trimethylsilyl-α-D-glucopyranoside is preferentially removed by methanolysis, using basic or acidic catalysts, giving methyl 2,3,4-tri-O-trimethylsilyl-α-D-glucopyranoside in high yield (>80%). Reaction of the latter with acetic anhydride, benzoyl chloride, or phenyl isocyanate produces the corresponding 6-substituted derivatives in quantitative yield. The trimethylsilyl residues from the latter compounds are hydrolyzed by 50% aqueous methanol with the concomitant formation of 6-O-acetyl, 6-O-benzoyl, or 6-carbanilate derivatives of methyl α-D-glucopyranoside in excellent yield. Chemical and proton magnetic resonance (p.m.r.) studies established the structure of methyl 2,3,4-tri-O-trimethylsilyl-α-D-glucopyranoside, and of subsequent derivatives prepared from this compound. Infrared and p.m.r. evidence is offered to support conclusions regarding the conformation of the groups or atoms attached to C6 and C5 of the glucoside residue in some of these compounds.

The conformational preference and barrier to internal rotation of an equatorial 3,5-dichlorophenyl group by the J method. Derivatives of cyclohexane, 1,3-dithiane, 1,3-dioxane, and 1,3-dioxolane

1979 ◽  
Vol 57 (3) ◽  
pp. 355-359 ◽  
Author(s):  
Ted Schaefer ◽  
Walter Niemczura ◽  
Werner Danchura
Keyword(s):  
Magnetic Resonance ◽  
Molecular Mechanics ◽  
Internal Rotation ◽  
Phenyl Ring ◽  
Proton Magnetic Resonance ◽  
Conformational Preference ◽  
Molecular Mechanics Calculations ◽  
X Ray ◽  
Carbon Carbon Bond ◽  
Derivatives Of

We report the preparation and the analysis of the phenyl ring proton magnetic resonance spectra of 3,5-dichlorophenylcyclohexane and of the 2-(3,5-dichlorophenyl) derivatives of 1,3-dioxane, 1,3-dithiane, and 1,3-dioxolane. With the exception of the dioxolanes these compounds exist predominantly as the equatorial isomers. The J method is used to show that the phenyl moiety prefers the conformation in which the α C—H bond lies in the phenyl plane. The predominantly twofold barriers to rotation about the carbon–carbon bond between the two ring systems are 2.0 ± 0.3, 0.4 ± 0.2, 2.2 ± 0.3, 0.85 ± 0.3 kcal/mol for these compounds, in the order given above. The low value for the barrier in the 1,3-dioxane derivative agrees reasonably well with molecular mechanics calculations and with the results of calorimetric and X-ray studies on equatorial 2-phenyl-1,3-dioxane.

ChemInform Abstract: PROTON MAGNETIC RESONANCE SPECTRA OF ANIONIC Σ-COMPLEXES OF TRINITROBENZENE WITH CYCLOPENTADIENYL AND INDENYL DERIVATIVES OF TIN

1976 ◽  
Vol 7 (50) ◽  
pp. no-no
Author(s):  
YU. A. USTYNYUK ◽  
G. A. ARTAMKINA ◽  
YU. N. LUZIKOV ◽  
YU. K. GRISHIN ◽  
A. A. AZIZOV ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Derivatives Of ◽  
Magnetic Resonance Spectra

Cycloaddition d'ylures d'azométhine dérivés de la 3,4-dihydro-6,7-diméthoxy-3-méthoxycarbonyl-isoquinoléine

1991 ◽  
Vol 69 (7) ◽  
pp. 1156-1160 ◽  
Author(s):  
Tahar Lakhlifi ◽  
Ahmed Sedqui ◽  
Bernard Laude ◽  
Nguyen Dinh An ◽  
Joël Vebrel
Keyword(s):  
Magnetic Resonance ◽  
Key Words ◽  
Proton Magnetic Resonance ◽  
Azomethine Ylide ◽  
Magnetic Resonance Data ◽  
Resonance Data ◽  
Azabicyclic Compounds ◽  
Derivatives Of ◽  
Proton Magnetic Resonance Data

Three azomethine ylide precursors including the methyl 3,4-dihydro-6,7-dimethoxyisoquinoline-3carboxylate moiety were synthesized. The 1,3-dipolar species formed from these products react with activated dipolarophilic olefines leading diastereospecifically to derivatives of 4′,5′-dimethoxy-1,2-benzo-4,7-imino-4-methoxycarbonyl-1-cycloheptene. Proton magnetic resonance data allowed the determination of the stereochemistry of the cycloadducts. Key words: cyclic azomethine ylide, azabicyclic compounds, stereochemistry.

A proton magnetic resonance determination of the small rotational barriers about the C—Si bond in phenyl derivatives of chloro and methyl silanes

1977 ◽  
Vol 55 (3) ◽  
pp. 557-561 ◽  
Author(s):  
William J. E. Parr ◽  
Ted Schaefer
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Molecular Orbital Calculations ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling ◽  
Derivatives Of ◽  
Low Energy Conformations

The long-range spin–spin coupling constants between protons bonded to silicon and ring protons in C6H5SiH3, C6H5SiH2Cl, C6H5SiH2CH3, C6H5SiHCl2, and C6H5SiH(CH3)2 are determined from the proton magnetic resonance spectra of benzene solutions. A hindered rotor treatment of the barrier to internal rotation about the C—Si bond, in conjunction with the coupling constants over six bonds, allows the deduction of the low-energy conformations for C6H5SiH(CH3)2 and for C6H5SiHCl2, as well as of barriers of 1.0 ± 0.2 kcal/mol. The approach becomes less reliable for C6H5SiH2CH3 and for C6H5SiH2Cl and, particularly for the latter compound, the derived barrier is very likely an upper limit only. Ab initio molecular orbital calculations of the conformational energies are reported for C6H5SiH3, C6H5SiH2Cl, and for C6H5SiHCl2.

The proton magnetic resonance spectra of N-nitroso derivatives of sarcosine, proline and iminodiacetic acid

1971 ◽  
Vol 24 (9) ◽  
pp. 1949 ◽  
Author(s):  
FHC Stewart
Keyword(s):  
Magnetic Resonance ◽  
Long Range ◽  
Proton Magnetic Resonance ◽  
Iminodiacetic Acid ◽  
Conformational Isomerism ◽  
Nitroso Group ◽  
Restricted Rotation ◽  
Derivatives Of ◽  
Shielding Effects ◽  
Magnetic Resonance Spectra

The proton magnetic resonance spectra of various N-nitroso derivatives of sarcosine, L-proline, and iminodiacetic acid, including some protected dipeptides, have been obtained. Magnetic non-equivalence and conformational isomerism arising from restricted rotation of the nitroso group are discussed in relation to the reported behaviour of other nitrosamines. Long-range shielding effects on protons at a considerable distance from the anisotropic nitrosamino centre were readily detected with these compounds.

Proton magnetic resonance and mass spectrometric studies on derivatives of sodium 2-O-α-D-mannopyranosyl-D-glycerate and related compounds

1969 ◽  
Vol 47 (21) ◽  
pp. 4083-4086 ◽  
Author(s):  
J. N. C. Whyte
Keyword(s):  
Magnetic Resonance ◽  
Methyl Ester ◽  
Proton Magnetic Resonance ◽  
Mass Spectra ◽  
Red Alga ◽  
Mass Spectrometric ◽  
Derivatives Of ◽  
Related Compounds

The proton magnetic resonance (p.m.r.) and mass spectra of the methyl ester pentaacetate of sodium 2-O-α-D-mannopyranosyl-D-glycerate from the red alga Rhodomela larix are compared to those of related compounds to affirm the assigned structure.

Communications. Proton magnetic resonance shifts of the trimethylsilyl derivatives of silicate materials

The Analyst ◽  
1982 ◽  
Vol 107 (1270) ◽  
pp. 116 ◽  
Author(s):  
B. R. Currell ◽  
H. G. Midgley ◽  
J. R. Parsonage ◽  
E. A. Vidgeon
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Trimethylsilyl Derivatives ◽  
Derivatives Of ◽  
Silicate Materials

Organophosphorus Compounds. I. 2-Chloroalkylphosphonic Acids as Phosphorylating Agents

1963 ◽  
Vol 16 (4) ◽  
pp. 596 ◽  
Author(s):  
JA Maynard ◽  
JM Swan
Keyword(s):  
Magnetic Resonance ◽  
Proton Magnetic Resonance ◽  
Organophosphorus Compounds ◽  
Chloride Ion ◽  
The Other ◽  
High Yield ◽  
Neutral Solution ◽  
Phosphate Ion ◽  
Phosphorus Containing ◽  
Group 2

Alcohols and phenols are phosphorylated in high yield by reaction with various 2-chloroalkylphosphonic acids at 20-50�C in the presence of three or more molar equivalents of cyclohexylamine or triethylamine, the other products being the corresponding alk-1-ene and chloride ion. The reaction probably proceeds by attack of an ROH molecule on the phosphorus atom of a doubly-ionized phosphonate group. 2-Chlorodecyl-, 10-carboxy-2-chlorodecyl-, and 2-chloro-octylphosphonic acid decompose rapidly in neutral solution giving chloride ion, phosphate ion, and the corresponding alk-1-ene. In the absence of hydroxylic compounds, 2-chlorodecylphosphonic acid is decomposed by cyclohexylamine to dec-1-ene and a product which appears to be N-cyclohexylphosphoramidate; t-amines and also aniline cause dehydrohalogenation to dec-1-enylphosphonic acid. The proton magnetic resonance spectra of most of the phosphorus-containing substances described herein are recorded.

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