Raman intensity and conjugation. IV-determination of the conjugation between a phenyl ring and a carbonyl group by Raman intensity

1977 ◽  
Vol 6 (6) ◽  
pp. 314-318 ◽  
Author(s):  
E. D. Schmid ◽  
P. Schlenker ◽  
R. R. M. Brand
Keyword(s):  
Carbonyl Group ◽  
Phenyl Ring ◽  
Raman Intensity

Absolute Raman intensity measurements and determination of the vibrational second hyperpolarizability of adamantyl endcapped polyynes

2012 ◽  
Vol 43 (9) ◽  
pp. 1293-1298 ◽  
Author(s):  
A. Lucotti ◽  
M. Tommasini ◽  
D. Fazzi ◽  
M. Del Zoppo ◽  
W. A. Chalifoux ◽  
...  
Keyword(s):  
Raman Intensity ◽  
Second Hyperpolarizability ◽  
Intensity Measurements

scholarly journals The use of carbonyl group anisotropy effect in determination of the relative configuration of carbapenams

ARKIVOC ◽  
2014 ◽  
Vol 2014 (3) ◽  
pp. 143-153 ◽  
Author(s):  
Olga Staszewska-Krajewska ◽  
Wojciech Bocian ◽  
Magdalena Maciejko ◽  
Piotr Szcześniak ◽  
Krzysztof Szymczak ◽  
...  
Keyword(s):  
Carbonyl Group ◽  
Relative Configuration ◽  
Anisotropy Effect

Mechanism of interference with the Jaffé reaction for creatinine.

1987 ◽  
Vol 33 (7) ◽  
pp. 1129-1132 ◽  
Author(s):  
M H Kroll ◽  
N A Roach ◽  
B Poe ◽  
R J Elin
Keyword(s):  
Carbonyl Group ◽  
Equilibrium Constants ◽  
Molar Absorptivity ◽  
Reaction Products ◽  
Cyclic Ketones ◽  
Common Structure ◽  
Aliphatic Ketones ◽  
Rate Of Reaction ◽  
The Common

Abstract We investigated the mechanism of the Jaffé reaction for determination of creatinine by studying the spectrophotometric, kinetic, and equilibrium properties of the reaction of picrate with creatinine and with cyclic and aliphatic ketones. Absorbance spectra for the reaction products of picrate with all the ketones were superimposable with that of creatinine (Amax, 490 nm). Cyclic ketones not containing nitrogen had a molar absorptivity less than half that of creatinine and equilibrium constants approximately 0.01 that of creatinine. Aliphatic ketones, except for benzylacetone, had molar absorptivities similar to that of creatinine, but all of these compounds had equilibrium constants approximately a tenth or less that of creatinine. The common structure for all of the compounds reacting with picrate is the carbonyl group. The variable magnitude of interference for aliphatic and cyclic ketones is ascribable to the different rate constants, molar absorptivities, and equilibrium constants as compared with creatinine. Structures adjacent to the carbonyl group significantly affect the absorptivity and equilibrium constant, but steric hindrance is the major factor affecting the rate of reaction. We postulate that the carbonyl group is required for the Jaffé reaction, and we suggest a mechanism for the reaction.

Structural Study of Flavonoids and Their Protonated Forms

1996 ◽  
Vol 51 (11-12) ◽  
pp. 784-790 ◽  
Author(s):  
Jaroslav Tóth ◽  
Milan Remko ◽  
Milan Nagy
Keyword(s):  
Carbonyl Group ◽  
Quantum Chemical ◽  
Phenyl Ring ◽  
Chemical Methods ◽  
Quantum Chemical Methods ◽  
Ring Rotation ◽  
Protonated Forms ◽  
Conformational Properties ◽  
Ether Oxygen ◽  
Stable Structures

The highly successful semiempirical quantum chemical methods AM1 (Austin Model 1) and PM3 (a reparametrization of AM1) were applied to an investigation of the conformational properties of flavone, 3-hydroxyflavone, isoflavone and 2-hydroxyisoflavone. The most stable structures correspond to the non-planar forms with an angle of phenyl ring rotation out of the chromone moiety from a relatively narrow interval (28° - 38°). The mono- and diprotonation of these compounds was also investigated. The prominent site of protonation is the oxygen of the carbonyl group with a protonation enthalpy from the interval of about 900 -920 kJ.mol-1. The protonation enthalpy for protonation of the ether oxygen was computed to be about 200 kJ.mol-1 lower. Adding a second proton to monoprotonated species studied resulted in much lower protonation enthalpies compared to monoprotonation. The geometry of the studied compounds upon protonation changed considerably.

scholarly journals Isoprenoid biosynthesis in bacteria: a novel pathway for the early steps leading to isopentenyl diphosphate

1993 ◽  
Vol 295 (2) ◽  
pp. 517-524 ◽  
Author(s):  
M Rohmer ◽  
M Knani ◽  
P Simonin ◽  
B Sutter ◽  
H Sahm
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Carbonyl Group ◽  
Zymomonas Mobilis ◽  
Biosynthetic Pathway ◽  
Isoprenoid Biosynthesis ◽  
Dihydroxyacetone Phosphate ◽  
Isopentenyl Diphosphate ◽  
Valine Biosynthesis

Incorporation of 13C-labelled glucose, acetate, pyruvate or erythrose allowed the determination of the origin of the carbon atoms of triterpenoids of the hopane series and/or of the ubiquinones from several bacteria (Zymomonas mobilis, Methylobacterium fujisawaense, Escherichia coli and Alicyclobacillus acidoterrestris) confirmed our earlier results obtained by incorporation of 13C-labelled acetate into the hopanoids of other bacteria and led to the identification of a novel biosynthetic route for the early steps of isoprenoid biosynthesis. The C5 framework of isoprenic units results most probably (i) from the condensation of a C2 unit derived from pyruvate decarboxylation (e.g. thiamine-activated acetaldehyde) on the C-2 carbonyl group of a triose phosphate derivative issued probably from dihydroxyacetone phosphate and not from pyruvate and (ii) from a transposition step. Although this hypothetical biosynthetic pathway resembles that of L-valine biosynthesis, this amino acid or its C5 precursors could be excluded as intermediates in the formation of isoprenic units.

On the determination of the carbonyl group by the hydroxylamine method

1949 ◽  
Vol 14 ◽  
pp. 162-176 ◽  
Author(s):  
J. Wanka ◽  
M. Jureček ◽  
F. Holánek
Keyword(s):  
Carbonyl Group

Massen-, NMR-und IR-spektroskopische Untersuchungen an Berylliumchelaten substituierter Acetoacetanilide / Investigations of Beryllium Chelates with Substituted Acetoacetanilides by Mass, NMR and IR Spectroscopy

1978 ◽  
Vol 33 (2) ◽  
pp. 183-189 ◽  
Author(s):  
A. Kettrup ◽  
P. Ackermann ◽  
W. Riepe
Keyword(s):  
Chemical Shift ◽  
Phenyl Ring ◽  
Mass Spectra ◽  
Amide Group ◽  
Amide Proton ◽  
Group Influence ◽  
Ir Spectrometry ◽  
Stretching Vibrations ◽  
The Stability

Correlation of measurements by mass, NMR and IR spectrometry were carried out for the determination of the structure and stability of beryllium chelates of substituted aceto-acetanilides. The substituents at the phenyl ring of the amide group influence the position of the stretching vibrations of the beryllium-oxygen bonds, the chemical shift of the amide proton and also the abundance ratios of specific ions of fragments in the respective mass spectra. All these results are correlated and represent data for the stability of these metal chelates

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