Dimethylboric anhydride: a convenient preparation and full characterization

1969 ◽  
Vol 47 (4) ◽  
pp. 569-575 ◽  
Author(s):  
G. F. Lanthier ◽  
W. A. G. Graham
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Complex Formation ◽  
Lewis Acid ◽  
Complete Characterization ◽  
Full Characterization ◽  
Hydrolysis Of ◽  
Convenient Preparation ◽  
Reference Acid ◽  
Acid Character

Dimethylboric anhydride, (CH3)2BOB(CH3)2, has been prepared by limited hydrolysis of dimethylboron chloride and complete characterization has been carried out. The Lewis acid character of boron and the donor strength of oxygen have been studied using tensimetric and nuclear magnetic resonance techniques.Evidence for boron–oxygen π-bonding obtained from complex formation studies, using trimethylboron as a reference acid, is presented and discussed. The reduced acidity of the boron atoms, in comparison with trimethylboron, is discussed in terms of boron–oxygen π-bonding.

Rapid Method for Analyzing Resmethrin Content in Formulations and Determining the cis-trans Ratios

1972 ◽  
Vol 55 (6) ◽  
pp. 1328-1330
Author(s):  
Robert R Heath
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Rapid Method ◽  
Nuclear Magnetic Resonance Spectrum ◽  
Resonance Spectrum ◽  
Geometrical Isomers ◽  
Petroleum Distillates ◽  
Gasliquid Chromatography ◽  
Infrared Method ◽  
Hydrolysis Of

Abstract Total resmethrin was determined in test formulations prepared in petroleum distillates and in micronized dust formulations by gasliquid chromatography. The ratio of the 2 geometrical isomers was obtained from the nuclear magnetic resonance spectrum of the parent acid after hydrolysis of resmethrin. This method of determining isomer ratios was faster and somewhat more accurate than the infrared method.

Syntheses of methyl glycosides of 6-deoxyheptoses

1994 ◽  
Vol 72 (1) ◽  
pp. 247-251 ◽  
Author(s):  
Gerald O. Aspinall ◽  
Armando G. McDonald ◽  
Ramesh K. Sood
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Gas Chromatography ◽  
Magnetic Resonance ◽  
Potassium Cyanide ◽  
Diisobutylaluminum Hydride ◽  
Carbohydrate Polymers ◽  
Magnetic Resonance Data ◽  
Resonance Data ◽  
Campylobacter Species ◽  
Hydrolysis Of

Methyl α-D-glycopyranosides of 6-deoxy-D-altro-heptose, 6-deoxy-D-manno-heptose, and 6-deoxy-D-talo-heptose have been prepared. Displacements of methyl 2,3,4-tri-O-benzylhexopyranoside 6-trifluoromethanesulfonates with potassium cyanide, followed by reduction of the resulting heptopyranosidurononitriles with diisobutylaluminum hydride, hydrolysis of the imine, further reduction with sodium borohydride, and catalytic O-debenzylation, give the corresponding methyl 6-deoxyheptopyranosides. Configurational change at C-4 of methyl 6-deoxy-7-O-tert-butyldiphenylsilyl-α-D-manno-heptopyranoside to give the talo isomer was effected by oxidation followed by stereoselective reduction. 1H nuclear magnetic resonance data of the glycosides, and gas chromatography of acetylated glycosides of (R)- and (S)-2-butanol serve to establish ring and enantiomeric configurations of the parent sugars when these are encountered as constituents of lipopolysaccharides or extracellular carbohydrate polymers, as in Campylobacter species.

Polar trifluoromethylation reactions: the formation of bis(trifluoromethyl)iodine(III) compounds and trifluoromethyl iodine(III) cations and anions

1991 ◽  
Vol 69 (2) ◽  
pp. 327-333 ◽  
Author(s):  
Wieland Tyrra ◽  
Dieter Naumann
Keyword(s):  
Nuclear Magnetic Resonance ◽  
New Species ◽  
Magnetic Resonance ◽  
Magnetic Resonance Spectroscopy ◽  
Key Words ◽  
Lewis Acid ◽  
Group Formation ◽  
Resonance Spectroscopy ◽  
By Products ◽  
Nuclear Magnetic

IX3 (X = Cl, OCOCF3, ONO2) reacts with Cd(CF3)2 complexes or Bi(CF3)3 to yield the corresponding CF3IX2 derivatives. 19F nuclear magnetic resonance spectroscopic evidence is found for [I(CF3)2]+ and I(CF3)2X (X = Cl, OCOCF3) in the reactions of CF3IX2 with Cd(CF3)2 complexes. During the reaction of CF3IF2 and Hg(CF3)2 the new species I(CF3)2F and cis-[I(CF3)2F2]− are identified by nuclear magnetic resonance spectroscopy. The reactions proceed under polar conditions and can be accelerated by the addition of a Lewis acid such as BF3, B(OCOCF3)3, or Sb(V) compounds. Difluoromethyl compounds are formed as by-products. Key words: polar trifluoromethylations, trifluoromethyl iodine(III) compounds, difluoromethyl group formation.

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