Trends in Alkyl Substituent Effects on Nucleophilic Reactions of Carbonyl Compounds: Gas-Phase Reactions between Amines and the Methoxy Methyl Cation

2004 ◽  
Vol 10 (2) ◽  
pp. 233-238 ◽  
Author(s):  
Lihn Bache-Andreassen ◽  
Einar Uggerud
Keyword(s):  
Gas Phase ◽  
Carbonyl Compounds ◽  
Substituent Effects ◽  
Alkyl Substituent ◽  
Gas Phase Reactions ◽  
Nucleophilic Reactions ◽  
Methyl Cation

Correlation between Alkyl Cation Affinities and Proton Affinities—A Means to Rationalise Alkyl Group Substituent Effects

2000 ◽  
Vol 6 (2) ◽  
pp. 131-134 ◽  
Author(s):  
Einar Uggerud
Keyword(s):  
Linear Relationship ◽  
Alkyl Group ◽  
Substituent Effects ◽  
Alkyl Substituent ◽  
Thermochemical Data ◽  
Proton Affinities ◽  
Alkyl Groups ◽  
Substituent Constants ◽  
Straight Lines ◽  
Methyl Cation

Using literature thermochemical data it is demonstrated that the known linear relationship between proton affinities and methyl cation affinities can be extended to other alkyl groups (ethyl, i-propyl, t-butyl). It is suggested that the slopes of the straight lines can be used to define a new set of alkyl substituent constants.

Gas phase basicities of fluorocarbonyl compounds. An ion cyclotron resonance investigation of the effects of fluorine and trifluoromethyl substituents on hydroxy carbonium ion stabilities

1981 ◽  
Vol 59 (18) ◽  
pp. 2689-2694 ◽  
Author(s):  
C. E. Doiron ◽  
T. B. McMahon
Keyword(s):  
Gas Phase ◽  
Carbonyl Compounds ◽  
Cyclotron Resonance ◽  
Substituent Effects ◽  
Ion Cyclotron Resonance ◽  
Proton Affinities ◽  
Resonance Investigation ◽  
Carbonium Ion ◽  
Hydrogen Bonding Interactions ◽  
Gas Phase Basicities

Gas phase proton affinities for a number of fluoro- and trifluoromethyl-substituted carbonyl compounds have been obtained using a combination of proton transfer equilibria and bracketing experiments. Absolute and relative substituent effects for F and CF3 on carbonyl basicities are determined and discussed in terms of inductive, resonance, polarization, and hydrogen bonding interactions. The data are used to interpolate basicities for HCOF and CF3CHO and are compared to theoretical ab initio calculations.

scholarly journals FLUORESCENCE HISTOCHEMISTRY OF BIOGENIC MONOAMINES A STUDY OF THE CAPACITY OF VARIOUS CARBONYL COMPOUNDS TO FORM FLUOROPHORES WITH BIOGENIC MONOAMINES IN GAS PHASE REACTIONS

1972 ◽  
Vol 20 (6) ◽  
pp. 435-444 ◽  
Author(s):  
STURE AXELSSON ◽  
ANDERS BJÖRKLUND ◽  
OLLE LINDVALL
Keyword(s):  
Acetic Acid ◽  
Gas Phase ◽  
Carbonyl Compounds ◽  
Glyoxylic Acid ◽  
Histochemical Demonstration ◽  
High Reactivity ◽  
Gas Phase Reactions ◽  
Cyclization Reactions ◽  
Biogenic Monoamines ◽  
Keto Acids

The capacity of biogenic amines to form fluorophores in histochemical gas phase reactions has been tested with 20 compounds having a carbonyl group (> C = O) as a common characteristic. Significant visible fluorescence was induced from catecholamines and indolamines with aldehydes, ketones, α-keto acids and carboxylic acids, suggesting that all of these compounds can enter fluorophore-forming cyclization reactions under the histochemical gas phase conditions. The most "reactive" reagents are found among the low molecular aldehydes, and formaldehyde and glyoxylic acid seem to be the most suitable reagents, combining high reactivity with good selectivity. Fluorescence, interesting for the histochemical demonstration of N-acetylated indolamines, was obtained from melatonin and N-acetyl-5-hydroxytryptamine with some acid reagents (glyoxylic acid, formic acid, acetic acid and pyruvic acid). A direct cyclodehydration according to the classical Bischler-Napieralski reaction is the most likely mechanism underlying this fluorophore formation. The usefulness of the various carbonyl reagents for the fluorescence histochemical demonstration of other biologically interesting amines, such as histamine, p-tyramine and octopamine, has been specially investigated.

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