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Aldehyde Condensations

Aldehydes condense with alcohols in the presence of a catalyst (1-2-5 per... [Pg.319]

Claisen-Schmidt reaction. Aromatic aldehydes condense with aliphatic or mixed alkyl-aryl ketones in the presence of aqueous alkali to form ap-unsaturated ketones ... [Pg.709]

R = vinyl. With aromatic substituents the fulvenes ate deep ted. The aldehyde condensation products ate also strongly colored but tesinify so easily that it is difficult to isolate them in the pure form. [Pg.431]

Chloro-a,/3-unsaturated aldehydes condense with ammonium thiocyanate to give isothiazoles (76EGP122249). 2,3-Diphenylcyclopropenone reacts with iV-sulfinyl-cyclohexylamine in the presence of nickel tetracarbonyl to give the isothiazolin-3-one 1-oxide (197) (79SST(5)345). Cholesteryl acetate reacts with trithiazyl trichloride in pyridine to give the isothiazolo steroid (198) (77JCS(P1)916). [Pg.169]

Sour gas sweetening may also be carried out continuously in the flowline by continuous injection of H2S scavengers, such as amine-aldehyde condensates. Contact time between the scavenger and the sour gas is the most critical factor in the design of the scavenger treatment process. Contact times shorter than 30 sec can be accommodated with faster reacting and higher volatility formulations. The amine-aldehyde conden-... [Pg.177]

The advantages of amine-aldehyde condensates are water (or oil) soiu ble reaction products, lower operating temperatures, low eorrosivenL to, ind no reactivity with hydrocarbons... [Pg.178]

The second line of circumstantial evidence quoted in support of this hypothesis is the ready formation of l,2,3,4-tetrahydro-/3-carboline derivatives under pseudo-physiological conditions of temperature, pH, and concentration. Tryptamine and aldehydes, trypt-amine and a-keto acids, and tryptophan and aldehydes condense at room temperature in a Pictet-Spengler type intramolecular Mannich reaction in the pH range 5.2-8.0 (cf. Section III, A, 1, a). It was argued that experiments of this type serve as models for biochemical reactions and may be used in evidence. [Pg.197]

Aliphatic and aromatic aldehydes condensed with 2-amino-(62BRP898414), 5-amino- (80AJC1147), or 8-amino-l,2,4-triazolo[l,5-cjpyrimidines (68JOC530) to give the related Schiff bases. Treatment of the 2-amino-5-methyl-l,2,4-triazolo[l,5-c]quinazoline 11 with formaldehyde and piperidine in the presence of acetic acid gave the 2-hydroxymethyl-amino-5-(2-piperidinoethyl) derivative 172. Utilization of aromatic aldehydes and piperidine in this reaction gave the 2-arylideneamino-5-styryl derivatives 173 (68CB2106) (Scheme 67). [Pg.377]

Pyruvic Acid Compounds.—Lubrzynska and Smedley have recently shown that a number of aldehydes such as heliotropin, anisic aldehyde, benzaldehyde, and cinnamic aldehyde, condense with pyruvic acid in slightly alkaline solution, with the formation of )8-unsaturated-a-ketonic acids. For example, if heliotropin and pyruvic acid in alkaline solution be left standing for about eight days at ordinary temperature, dihydroxy-methylene-benzal-pyruvic acid is formed. This body forms yellow needles, melting at 163° Similarly, anisic aldehyde yields methoxy-benzal-pyruvic acid, melting at 130° and cinnamic aldehyde yields cinnamal-pyruvic acid, melting at 73°. [Pg.179]

Uses of Formaldehyde. Formaldehyde is the simplest and most reactive aldehyde. Condensation polymerization of formaldehyde with phenol, urea, or melamine produces phenol-formaldehyde, urea formaldehyde, and melamine formaldehyde resins, respectively. These are important glues used in producing particle hoard and plywood. [Pg.153]

Scheme 5. Ketophosphonate-aldehyde condensation in the total synthesis of a tylosin system. Scheme 5. Ketophosphonate-aldehyde condensation in the total synthesis of a tylosin system.
V-phenyltrifluoro-methanesulfoni-mide 458, 593 f., 715, 761, 773, phosphonate condensation 276 phosphonate-aldehyde condensation... [Pg.795]

Ethyl (Z)-2-bromomethyl-2-heptenoate and aldehydes condense on reaction with chromium(II) chloride to furnish cw-3,4-disubstituted dihydro-3-methylene-2(3 //)-( uranones exclusively16, indicating that a (Z)-allylchromium complex might serve as reactive intermediate in the. mv-selec-tive addition step due to the bulky 2-substitucnt. Alternatively, an acyclic transition state for the reaction of the ( )-diastereomer, mediated by the Lewis acid dichloroaluminum hydride, has been discussed16. [Pg.436]

The stereochemical outcome of the reaction is strongly dependent on the nature of the base and the aldehyde condensation time, reaction temperature, and the ETA ratio of the azaenolate. The enantioselectivity of the reaction increases with increasing bulk of the aldehyde residue. [Pg.604]

Hydroaminomethylation is hydroformylation coupled to amine-aldehyde condensation followed by hydrogenation. The hydroformylation reaction establishes... [Pg.224]

A Friedel-Crafts-type reaction of phenols under basic conditions is also possible. Aqueous alkaline phenol-aldehyde condensation is the reaction for generating phenol-formaldehyde resin.34 The condensation of phenol with glyoxylic acid in alkaline solution by using aqueous glyoxylic acid generates 4-hydroxyphenylacetic acid. The use of tetraalkylammonium hydroxide instead of sodium hydroxide increases the para-selectivity of the condensation.35 Base-catalyzed formation of benzo[b]furano[60]- and -[70]fullerenes occurred via the reaction of C60CI6 with phenol in the presence of aqueous KOH and under nitrogen.36... [Pg.208]

Numerous other aldehyde condensation reactions of five-membered heterocycles have been utilized in the synthesis of the central pyridine core. Paulmier and co-workers employed the condensation of 3-aminothiophenes 114 with aldehydes to give bis-thiophenylpyridines 115 (Equation 25) <1996JHC9>. [Pg.727]

Fig. 11. Sugar aldehydes condensed directly on pyrrole derivatives by Lindsey s chemistry. Fig. 11. Sugar aldehydes condensed directly on pyrrole derivatives by Lindsey s chemistry.
Phosphites can undergo hydrolysis to phosphorus acid. Aldehyde condensation can give trace levels of water. The phosphorus acid in turn can catalyze further hydrolysis. Acidity control should be considered for any homogeneous catalytic process. [Pg.26]

Selective Condensation of Vaporized Organophosphorus Ligand. Certain phosphorus ligands have sufficient volatility that portions may be volatilized when aldehyde and higher boiling aldehyde condensation byproducts are separated from the catalyst solution in, for example, a liquid recycle vaporizer. The phosphorus ligand may be condensed, recovered and returned to the catalyst solution [35] according to the procedure disclosed in US 5,110,990. [Pg.31]

This process is illustrated in Figure 2.10, where butanal liquid is sprayed into vaporized butanal, heavies and a phosphine such as triphenylphosphine. Example No. 10 of Table 2 of US 5,110,990 illustrates how by using this technique, 99% of the triphenylphosphine in the stream may be recovered while allowing 97% of the contained aldehyde condensation by-products to remain in the vapor. [Pg.32]

Capture of Active Catalyst Using Solid Acidic Support with H2 Elution. The limit on the practical life of a catalyst solution may be determined by several factors including the presence of poisons or inhibitors, the buildup of less soluble materials such as the oxidation products of organophosphorus ligands, or an increase in the concentration of heavy aldehyde condensation products in the catalyst solution. In the latter case, there may be substantial amounts of active catalyst, but it is in a solvent that is unsuitable. Alternately, active rhodium catalyst may have been carried over with product. Technology has been disclosed [39] that permits the isolation of an active metal hydride catalyst. Steps include ... [Pg.34]

The separation of rhodium hydride complex from a stream comprising catalyst and high molecular weight aldehyde condensation products using a carboxylic acid functionalized ion exchange resin in illustrated schematically in Figure 2.12. [Pg.35]

Krausz el al. have synthesised two series of amino acid porphyrinylsugar derivatives (Fig. 5). One of them involves the coupling of adequate glycoporphyrin derivatives, prepared by pyrrole/aldehyde condensation methodology, with 9-fluorenylmethoxycarbonyl-L-alanine (Fmoc-L-alanine) to give the tri-, di-, and mono-alanine glycoporphyrin derivatives 54—57 after the deprotection step the other series (58) involves a glucosylamino acid moiety instead of the alanine in their preparation.21,44... [Pg.204]

Aldehydes condense with compounds containing a reactive methyl-or methylene-group to form unsaturated ketones, e.g. [Pg.181]

Cannizzaro s reaction probably proceeds in such a way that two molecules of aldehyde condense to form an ester which is then hydrolysed to alcohol and acid ... [Pg.221]

A. The Basic Series.—In general, aromatic aldehydes condense with aromatic amines in the presence of zinc chloride to form triphenylmethane derivatives (0. Fischer) phenols and phenyl ethers behave similarly in the presence of concentrated sulphuric acid (Baeyer). The products formed are the leuco-compounds of well-known dyes. [Pg.327]


See other pages where Aldehyde Condensations is mentioned: [Pg.194]    [Pg.746]    [Pg.156]    [Pg.425]    [Pg.438]    [Pg.439]    [Pg.442]    [Pg.448]    [Pg.793]    [Pg.99]    [Pg.1243]    [Pg.94]    [Pg.209]    [Pg.21]    [Pg.31]    [Pg.32]    [Pg.35]    [Pg.232]   
See also in sourсe #XX -- [ Pg.969 ]

See also in sourсe #XX -- [ Pg.228 , Pg.230 ]

See also in sourсe #XX -- [ Pg.293 , Pg.482 ]

See also in sourсe #XX -- [ Pg.330 ]

See also in sourсe #XX -- [ Pg.228 , Pg.230 ]

See also in sourсe #XX -- [ Pg.750 , Pg.754 ]

See also in sourсe #XX -- [ Pg.57 ]




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1,4-Diacetylpiperazine-2,5-dione, condensation with aldehydes

Acid-Catalyzed Condensations of Heterocyclic Compounds and Aldehydes

Acid-catalyzed condensation aldehydes

Addition of an Enolate to Ketones and Aldehydes (a Condensation)

Aldehyde Condensation Polymers

Aldehyde carbonyl condensation reactions

Aldehyde condensation enamines

Aldehyde condensation nitriles

Aldehyde condensation nitrones

Aldehyde condensation reaction

Aldehyde condensation structures

Aldehyde-anthocyanin condensation

Aldehyde-condensing agent

Aldehyde-ketophosphonate condensation

Aldehyde-mediated condensation

Aldehyde-tannin condensation reactions

Aldehydes Perkin condensation

Aldehydes aldol condensation

Aldehydes aldol condensation with carbonyl

Aldehydes alkoxy. aldol condensation reactions

Aldehydes and ketones, condensation with

Aldehydes base-catalyzed condensations

Aldehydes condensation with diketones

Aldehydes condensation with heteroatom-substituted

Aldehydes condensation with ketones

Aldehydes condensation with phenols

Aldehydes condensation, double, with

Aldehydes condensations with anhydrides, acetic anhydride

Aldehydes condensations, 1,2-phenylenediamines, potassium

Aldehydes, Knoevenagel condensation

Aldehydes, addition derivatives condensation reactions

Aldehydes, catalytic condensation

Aldehydes, catalytic condensation with esters

Aldehydes, chiral condensation with achiral

Aldehydes, chiral condensation with achiral enolates

Aldehydes, condensation with

Aldehydes, condensation with sugars

Aldehydes, single-step condensation

Aldol Condensations with Aromatic Aldehydes

Aldol condensation aldehyde reaction with enolates

Aldol condensation piperidine aldehyde

Aldol condensation, aldehydes intramolecular

Aldol condensation, aldehydes mixed

Aldol condensations with aldehydes

Aldol type condensation of aldehydes

Aldol-type condensations of aldehydes with amides

Aldol-type condensations of aldehydes with esters

Alkaline phenol-aldehyde condensation

Allylsilane-aldehyde condensation

Amine-aldehyde condensation

Amine-aldehyde condensation products

Anthocyanins aldehydes-mediated condensation

Arene-Aldehyde Condensations

Aromatic aldehydes aldol condensation

Aromatic aldehydes condensation reactions

Aromatic aldehydes, condensation

Aryl aldehydes, aldol condensation

Benzoin aldehyde condensation

Carboxylic condensation with aldehydes

Carboxylic esters, base condensation, with aldehydes

Condensation between an aldehyde

Condensation between anthocyanins and flavanols mediated by aldehydes

Condensation ketones, aldehydes

Condensation of aliphatic aldehydes with 1,3-diketones and ammonia to lutidine derivatives

Condensation of an aldehyde and hippuric acid

Condensation reaction aldehydes/ketones

Condensation, of aldehydes

Condensation, of aldehydes and ketones

Condensations aldehydes with 1,2-phenylenediamines, potassium

Condensations of Aldehydes and Ketones The Aldol Reaction

Condensations of aldehydes and ketones the aldol condensation reaction

Decarboxylative Condensation, Aldehydes and Alcohols

Diaziridines condensation with aldehydes

Dipyrromethanes, condensation with aldehydes

Enamines from the Condensation of Aldehydes and Ketones with Secondary Amines

Enolates, aluminum condensation with aldehydes

Furan, 2-trimethylsiloxyaldol condensation reaction with aldehydes, stereoselectivity

Ketones, aldol condensation with aldehydes

Melamine aldehyde condensations

Melamine other aldehyde condensations

Methyl ethyl ketone, condensation with aldehydes

Methyl ketones, acylation condensation with aldehydes

Nitromethane, condensation with aldehydes

Other Aldehyde Condensations

Other Urea-Aldehyde Condensations

Oxazolidinones condensation with aldehydes

Phenol-aldehyde condensation

Phenol-aldehyde condensations aldehydes used

Phenol-aldehyde condensations catalysts

Phenol-aldehyde condensations compounding

Phenol-aldehyde condensations stability

Pyrazolones, condensation with aldehydes

Pyrroles condensation with aryl aldehydes

Reaction Condensation of an Aldehyde by Potassium Cyanide to a Benzoin

Reaction G Aldehyde-Amine Condensation

Rhodanines, condensation with aldehydes

Sugar aldehyde condensations

Sulfenimine, S-tritylsynthesis condensation of aldehydes with tritylsulfenamide

The Aldol Condensation of Ketones and Aldehydes

Urea-aldehyde condensations

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