Obtention de nouveaux squelettes diterpéniques lors de l'isomérisation d'époxydes diterpéniques sur alumine active

1988 ◽  
Vol 66 (7) ◽  
pp. 1558-1565 ◽  
Author(s):  
Martine Taran ◽  
Bernard Delmond
Keyword(s):  
Alumina Surface ◽  
Acid Base ◽  
Neutral Alumina ◽  
Base Mechanism ◽  
Grob Fragmentation ◽  
Derivatives Of

The isomerization of diterpene epoxides on active neutral alumina has established the existence of new rearrangements of the diterpene skeleton. Methyl 8,14β-epoxysandarcopimarate leads to bicyclic diterpene compounds by a Grob fragmentation, to derivatives of cleistanthane by a 1,2 migration of the vinyl substituent, as well as to one cycloditerpene compound. The 7,8 (or 8,9) derivatives of methyl isopimarate lead essentially to hydroxyolefins formed by a bifunctional acid–base mechanism at the alumina surface. [Journal translation]

Spectrophotometric study of the acid-base and optical properties of the 5-bromo and 5-chloro derivatives of 2-(2-pyridylazo)-5-(diethylamino)phenol (BrPADAP, ClPADAP) and their complexation equilibria with zinc(II) ions

1982 ◽  
Vol 47 (10) ◽  
pp. 2676-2691 ◽  
Author(s):  
Miroslav Macka ◽  
Vlastimil Kubáň
Keyword(s):  
Equilibrium Constants ◽  
Spectrophotometric Study ◽  
Graphical Analysis ◽  
Alkaline Media ◽  
Acid Base ◽  
Ethanol Medium ◽  
Triton X ◽  
Mixed Water ◽  
Derivatives Of

The optical and acid-base characteristics of BrPADAP and ClPADAP were studied in mixed water-ethanol and water-DMF media and in 10% ethanol medium in the presence of cationic, anionic and nonionic tensides. The composition, optical characteristics, molar absorption coefficients and equilibrium constants of the ML and ML2 complexes with zinc(II) ions were found by graphical analysis and numerical interpretation of the absorbance curves by the modified SQUAD-G program. Optimal conditions were found for the spectrophotometric determination of Zn(II) in the presence of 0.1% Triton X-100 or 1% Brij 35 in alkaline media with pH = 6.5-10. BrPADAP and ClPADAP are the most sensitive reagents (ε = 1.3-1.6 . 105 mmol-1 cm2 at 557 and 560 nm, respectively) for the determination of zinc with high colour contrast of the reaction (Δλ = 104 nm) and selectivity similar to that for the other N-heterocyclic azodyes (PAN, PAR, etc.).

scholarly journals The reactivity of aromatic and heterocyclic derivatives of hydrazine. Vіі. The acid-base properties of substituted 5,7-dichloro-9-hydrazine acridine

2016 ◽  
Vol 0 (1(85)) ◽  
pp. 12-14
Author(s):  
A. O. Deviatkina ◽  
O. M. Svechnikova ◽  
S. V. Kolisnyk ◽  
N. P. Kobzar ◽  
A. F. Vinnyk
Keyword(s):  
Acid Base ◽  
Heterocyclic Derivatives ◽  
Derivatives Of ◽  
Base Properties

Photocatalyzed Conversion of CO2 to CH4: An Excited-State Acid–Base Mechanism

2013 ◽  
Vol 117 (47) ◽  
pp. 12268-12279 ◽  
Author(s):  
Edward G. Look ◽  
Harry D. Gafney
Keyword(s):  
Excited State ◽  
Acid Base ◽  
Base Mechanism

Toward novel sulphur-containing derivatives of tetraazacyclododecane: synthesis, acid–base properties, spectroscopic characterization, DFT calculations, and cadmium(ii) complex formation in aqueous solution

2020 ◽  
Vol 44 (20) ◽  
pp. 8337-8350 ◽  
Author(s):  
Marianna Tosato ◽  
Marco Verona ◽  
Riccardo Doro ◽  
Marco Dalla Tiezza ◽  
Laura Orian ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Complex Formation ◽  
Dft Calculations ◽  
Spectroscopic Characterization ◽  
Acid Base ◽  
Derivatives Of ◽  
Base Properties

New sulphur derivatives of cyclen, with potential complementary properties with respect to known compounds, have been synthesized and studied.

scholarly journals High protein diets and acid-base mechanism

1933 ◽  
Vol 27 (5) ◽  
pp. 1430-1437
Author(s):  
Muriel Emma Bell
Keyword(s):  
High Protein ◽  
Acid Base ◽  
Base Mechanism ◽  
High Protein Diets ◽  
Protein Diets
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