Condensation reactions Perkin

Manufacture. The most widely employed method for the commercial synthesis of (H)-cinnamic acid uti1i2es ben2aldehyde, acetic anhydride, and anhydrous sodium or potassium acetate in a condensation reaction commonly referred to as the Perkin reaction (11). 

Introduction of the two-carbon fragment is a cornerstone of synthetic methodology and many of the condensation reactions frequently used have been known for decades, if not for a century. Examples include the malonic ester and acetoacetic ester reactions, the Perkin condensation, and the Doebner-... 

The forward synthetic reaction is a base-catalysed condensation reaction between two carbonyl compounds, the aldol condensation leading to -hydroxy-aldehydes or / -hydroxyketones followed by dehydration. This sequence is one of the most important carbon-carbon bond forming reactions, and aldol-type condensation reactions are considered in a number of other sections of the text, for example, the Doebner reaction (Section 5.18.3, p. 805), the Knoevenagel reaction (Section 5.11.6, p. 681), the Perkin reaction (Section 6.12.3, p. 1036) and the Robinson annelation reaction (Section 7.2). 

K. Oyama, K. Kihara, and Y. Nonaka, On the mechanism of the action of thermolysin kinetic study of the thermolysin-catalyzed condensation reaction of N-benzyloxy-carbonyl-t-aspartic add with L-phenyl-alanine methyl ester, J. Chem. Soc. Perkin Trans. 2 1981a, 356-360. 

Condensation reactions of the aldol type play an important part in heterocyclic chemistry. There are a large number of condensation reactions that are closely related to the aldol condensation. Each of these reactions has its own name Claisen, Dieckmann, Doebner, Knoevenagel, Perkin, to mention a few, but the chemistry is essentially the same as that of the aldol condensation. 

Furthermore, the carbanion also may be added to a carbonyl group of another molecule, with formation of a new CC bond. Synthetic applications are the aldol condensation and the diacetonealcohol condensation. The acid strength of CH bonds in alpha position to COO-, COOR, or CN groups is extremely low (p > 20) and condensation reactions of the corresponding anions must be carried out in the absence of water (Claisen, Perkin, and Knoevenagel condensations). 

Toda, F., Suzuki, T., Higa, S. Solvent-free Dieckmann condensation reactions of diethyl adipate and pimelate. J. Chem. Soc., Perkin Trans. 11998, 3521-3522. 

Liquid samples were regularly withdrawn with a filtering syringe and analyzed by a gas chromatograph (Perkin Ehner) equipped with an FID detector and using a capillary column (CPSilSCB, 25 m). All the isomers (Z, E) of crosscondensation and self condensation reactions have been separated and identified by H-NMR and GC-MS. Quantitative determinations were based on the measured response factors of the reactants and reaction products. We checked that reactions were carried without transfer limitations. The selectivity for a particular product was defined as the mmol of this product divided by the total mmol of heptanal converted. 

This reaction is related to the Bergmann-Stern Azlactone Synthesis, Claisen Condensation, and Perkin Reaction. 

The most important modification of the Perkin reaction was developed by Oglialoro using the sodium salt of acetic acid (e.g., phenylacetic acid, phenoxyacetic acid ) in condensation with acetic anhydride and an aldehyde (e.g., benzaldehyde, paraldehyde ). This type of reaction is referred to as the Perkin-Oglialoro reaction,Perkin-Oglialoro condensation, or Oglialoro modification. Other modifications include the use of different bases as the catalysts, (e.g., NaB(OMe)4-LiCl, CaH2, CsOAc, and CsF ), the use of microwave irradiation and cesium acetate or fluoride in combination with a small amount of pyridine as catalyst and the continuous distillation of acetic acid to enhance the conversion rate. ... 

Paal-Knorr Pyrrole Synthesis Parham Cyclization Passerini Reaction Patemo-Biichi Reaction Pauson-Khand Reaction Payne Rearrangement Pechmann Condensation Pechmann Pyrazole Synthesis Pellizzari Reaction Pelouze Synthesis Periodic Acid Oxidation Perkin Alicyclic Synthesis Perkin Reaction Perkin Rearrangement Perkow Reaction Peterson Reaction... 

The entire manifold of aldol-type condensation reactions. The aldol condensation itself (Equation 9.45, el seq) and all of those in Table 9.5 (viz. the Claisen, Stobbe, Perkin, and Knovenagel condensation reactions and the Robinson annulation). 

Condensation reactions between phthalic anhydride and aryl or alkyl anhydrides in a Gabriel modification of the Perkin reaction (Scheme 11) have provided an exceptionally flexible synthetic route to a number of alkylidene and arylidenephthalides (15, 120—127). These... 

Nyiondi-Bonguen E, Fondjo ES, Fomum ZT, Doepp D (1994) Condensation reactions of 3-amino-4-imino-4/f-thieno[3,4-c][l]benzopyran. J Chem Soc Perkin Trans 1 2191-2196... 

Aldehydes can also be converted to olefins by reaction with active methylene compounds [Eq. (4)] by the Knoevenagel, Perkin, Claisen, and aldol condensation reactions... 

Condensation reactions such as the Reformatskii reaction, Perkin reaction, malonic ester synthesis, and the Diels-Alder reaction afford acids or their esters in good yields. 

Perkin reaction A condensation between aromatic aldehydes and the sodium salts of fatty acids or their aromatic derivatives. The reaction between benzaldehyde and sodium ethanoate in the presence of ethanoic anhydride leads to sodium cinnamate... 

Perkin reaction. The condensation of an aromatic aldehyde with an acid anhydride in the presence of the sodium or potassium salt of the acid... 

Basic catalysts other than alkali acetates have been employed in the Perkin reaction thus salicylaldehyde condenses with acetic anhydride in the presence of triethylamine to yield coumarin (tlie lactone of the cis form of o-hydroxy-cinnamio acid) together with some of the acetyl derivative of the trans form (o-acetoxycoumaric acid) ... 

Here the phenylacetic anhydride, possessing more reactive a-hydrogen atoms, condenses with benzaldehyde to give a-phenylcinnamic acid. The preparation of the latter is an example of the Oglialoro modiflcation of the Perkin reaction. 

Furfural condenses with acetic anhydride and potassiuiu acetate to give furylacrylic acid (compare Perkin reaction, Cinnamic Acid, Section IV, 124) ... 

The reaction probably proceeds by an initial cyclisation of the acylamlnoacetic acid, followed by a Perkin type of condensation of the aldehyde with the active methylene unit ... 

Aldehydes and Ketones. Pyrrole aldehydes and ketones are somewhat less reactive than the corresponding benzenoid derivatives. The aldehydes do not undergo Cannizzaro or Perkin reactions but condense with a variety of compounds that contain active methylene groups. They also react with pyrroles under acidic conditions to form dipyrryhnethenes (26). The aldehydes can be reduced to the methyl or carbinol stmctures. The ketones undergo normal carbonyl reactions. 

Perkin condensation is the reaction between aromatic aldehydes and aliphatic acid anhydrides (in the presence of the sodium salt) to form p-arylacrylic acid... 

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