Other Condensation Reactions

This success does, however, have a drawback the urea concentrations required could not possibly have existed in the primeval ocean. Thus, as in the case of other condensation reactions, one has to assume that there were ponds or lagoons, in which the necessary reagent concentrations could build up via evaporation of water. 

Polymerizations, esterifications and other condensation reactions, diazo reactions, oxidation and reduction... 

The chelating ligands described in this section are often not commercially available, and are usually prepared by condensation reactions. Some examples are given in Schemes 4 and 5. It should be noted that many other condensation reactions, e.g. Schiff-base type reactions (Chapter 20), have been reported for the synthesis of novel chelating ligands. 

Although other condensation reactions with 4-aminopyridine are reported to fail, they have in most cases succeeded with 4-aminoquinoline.59 Dey and Joullie87 have prepared a series of trifluoro-methylbenzo[A]-l,6-naphthyridines by condensing ethyl trifluoro-methylacetoacetate with 4-aminoquinaldine. 

Table 8.9 Other Condensation Reactions of Carbonyl Compounds ...

Condensation reactions are widely used in solid-phase organic chemistry. Transformations proceed cleanly and in high yield. Traditional Claisen, Knoevenagel, imine, Man-nich, enamine and other condensation reactions are summarized in the next tables. 

It is, of course, possible to devise other condensation reactions to account for the anthraquinone formation. Sufficient data have not been published to make possible an evaluation of the significance of this reaction. 

There are other condensation reactions similar to the aldol and Claisen condensations ... 

This research continues the previous work to further determine the structural features that control chromatographic retention and to see if these features can be measured by spectrometric behavior. Approximately 30 other peropyrene-type PAHs have been synthesized, isolated, and characterized. These PAHs were the products of other condensation reactions of 1-phen-alenone-type ketones. 1-Phenalenone, 7H-benz[de]anthracen-7-one, and a pair of five-ring ketones were used as reactants. PAHs with 9-12 rings resulted. Their chromatography and spectrometry were studied. The new results agree with previous correlations between steric effects and chromatographic and spectral behaviors. 

Other Condensation Reactions. BF3-MeOH and BF3 OEt2 with ethanol are widely used in the esterification of various kinds of aliphatic, aromatic, and carhoxyhc acids the reaction is mild, and no rearrangement of double bonds occurs. This esterification is used routinely for stable acids prior to GLC analysis. Heterocyclic carboxylic acids, unsaturated organic acids, biphenyl-4,4 -dicarboxylic acid, 4-aminobenzoic acid, and the very sensitive 1,4-dihydrobenzoic acid are esterified directly. 

In addition to the formation of compounds containing a G=N— linkage by the condensation of primary amines with carbonyl compounds, several other condensation reactions leading to azomethine hnkages are known. 

This reaction has been adapted to quantitative volumetric work as is also the case with certain other condensation reactions, particularly the reaction with hydroxylamine. ... 

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