Reaction of polystyryllithium and 2-polystyryl-1,1-diphenyl-ethyllithium with methyl acetate, methyl benzoate and the corresponding acyl chlorides

1995 ◽  
Vol 196 (1) ◽  
pp. 85-98 ◽  
Author(s):  
Vladimir Zgonnik ◽  
Elena Melenevskaya ◽  
Jenö Kever ◽  
Larisa Litvinova ◽  
Alexander Khachaturov ◽  
...  
Keyword(s):  
Methyl Acetate ◽  
Methyl Benzoate ◽  
Acyl Chlorides ◽  
Acetate Methyl

Insulinotropic action of α-d-glucose pentaacetate: functional aspects

1997 ◽  
Vol 273 (6) ◽  
pp. E1090-E1101
Author(s):  
Willy J. Malaisse ◽  
Carmen Sánchez-Soto ◽  
M. Elena Larrieta ◽  
Marcia Hiriart ◽  
Hassan Jijakli ◽  
...  
Keyword(s):  
Ethyl Acetate ◽  
Insulin Release ◽  
Methyl Acetate ◽  
Cytochalasin B ◽  
Secretory Response ◽  
Coupling Mechanism ◽  
Functional Aspects ◽  
Acetate Methyl ◽  
Glucose Pentaacetate ◽  
Stimulate Insulin Release

The functional determinants of the insulinotropic action of α-d-glucose pentaacetate were investigated in rat pancreatic islets. The ester mimicked the effect of nutrient secretagogues by recruiting individual B cells into an active secretory state, stimulating proinsulin biosynthesis, inhibiting86Rb outflow, and augmenting45Ca efflux from prelabeled islets. The secretory response to the ester was suppressed in the absence of Ca2+ and potentiated by theophylline or cytochalasin B. The generation of acetate from the ester apparently played a small role in its insulinotropic action. Thus acetate, methyl acetate, ethyl acetate, α-d-galactose pentaacetate, and β-d-galactose pentaacetate all failed to stimulate insulin release. The secretory response to α-d-glucose pentaacetate was reproduced by β-d-glucose pentaacetate and, to a lesser extent, by β-l-glucose pentaacetate. It differed from that evoked by unesterifiedd-glucose by its resistance to 3- O-methyl-d-glucose,d-mannoheptulose, and 2-deoxy-d-glucose. It is concluded that the insulinotropic action of α-d-glucose pentaacetate, although linked to the generation of the hexose from its ester, entails a coupling mechanism that is not identical to that currently implied in the process of glucose-induced insulin release.

C=O Stretching vibrations in Raman and infrared spectra of simple esters

1982 ◽  
Vol 47 (8) ◽  
pp. 2027-2036 ◽  
Author(s):  
Jiří Dybal ◽  
Jan Štokr ◽  
Bohdan Schneider
Keyword(s):  
Infrared Spectra ◽  
Methyl Acetate ◽  
Butyl Acetate ◽  
Dielectric Constants ◽  
Fermi Resonance ◽  
Conformational Structure ◽  
Infrared And Raman Spectra ◽  
Tert Butyl ◽  
Acetate Methyl ◽  
Stretching Vibrations

Infrared and Raman spectra of methyl acetate, tert-butyl acetate, methyl pivalate and tert-butyl pivalate were measured in the liquid and crystalline states and solutions of different dielectric constants. In these molecules, the bands of the C=O str. vibrations are not affected by conformational structure. The shape and position of the band of the C=O str. vibration in methyl acetate are primarily determined by intermolecular order created by interactions of the permanent dipoles of the molecules. In methyl pivalate and in tert-butyl acetate, the shape of the carbonyl band is mainly determined by Fermi resonance.

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