Doebner

Doebner-von Miller reaction Condensation of an aromatic amine with an aldehyde or ketone in the presence of hydrochloric acid to form a quinoline derivative. A general method, thus aniline and ethanal give 2-methyl-quinoline (quinaldine) and p-phenetidine. 

Quinaldine (or 2-methylquinoline) can be prepared by the Doebner.Miller Synthesis, which in some respects is closely similar to the Skraup Synthesis (p. 297) but has some significant differences. 

To meet the needs of the advanced students, preparations have now been included to illustrate, for example, reduction by lithium aluminium hydride and by the Meerwein-Ponndorf-Verley method, oxidation by selenium dioxide and by periodate, the Michael, Hoesch, Leuckart and Doebner-Miller Reactions, the Knorr pyrrole and the Hantzsch collidine syntheses, various Free Radical reactions, the Pinacol-Pinacolone, Beckmann and Arbusov Rearrangements, and the Bart and the Meyer Reactions, together with many others. 

Ootonic acid may be prepared by condensing acetaldehyde with malonic acid in pyridine solution in the presence of a trace of piperidine (Doebner reaction see discussion following Section IV,123). 

This preparation is another example of the condensation of an aldehyde with malonic acid and pyridine to 3neld ultimately an ap-unsaturated acid (Doebner reaction). It is included here because, unlike the acids prepared from many of the lower aUphatic aldehydes, the product consists largely (about 95 per cent.) of the ap-isomeride and only about 5 per cent, of the PY-isomeride is present ... 

Sorbic acid is prepared by the condensation of crotonaldehj de with malonic acid ill the presence of pyridine at 100° (Doebner reaction) ... 

The Doebner condensation (or reaction) is a slight modification of the Knoevenagel reaction and consists in warming a solution of the aldehyde and... 

Priority for the use of pj-ridine as a catalyst shouki be assigned to Verley Doebner subsequently extended its use. 

Quinoline derivatives may be synthesised by heating aii aromatic amine with an aldehyde or a mixture of aldehydes in the presence of concentrated hydrochloric or sulphuric acid this synthesis is known as the Doebner - Miller reaction. Thus aniline and paraldehyde afford 2-methylquinohne or quinaldine. 

This is an example of the Doebner synthesis of quinoline-4-carboxylic acids (cinchoninic acids) the reaction consists in the condensation of an aromatic amine with pyruvic acid and an aldehj de. The mechanism is probably similar to that given for the Doebner-Miller sj nthesis of quinaldiiie (Section V,2), involving the intermediate formation of a dihydroquinoline derivative, which is subsequently dehydrogenated by the Schiff s base derived from the aromatic amine and aldehyde. 

Benzilic acid rearrangement Benzoin reaction (condensation) Blanc chloromethylation reaction Bouveault-Blanc reduction Bucherer hydantoin synthesis Bucherer reaction Cannizzaro reaction Claisen aldoi condensation Claisen condensation Claisen-Schmidt reaction. Clemmensen reduction Darzens glycidic ester condensation Diazoamino-aminoazo rearrangement Dieckmann reaction Diels-Alder reaction Doebner reaction Erlenmeyer azlactone synthesis Fischer indole synthesis Fischer-Speior esterification Friedel-Crafts reaction... 

By substituting paraldehyde for glycerol, 2-methylquinoline [27601-00-9] may be synthesized. The Skraup synthesis is regarded as an example of the broader Doebner-von Miller synthesis. In the case of the Skraup synthesis, the glycerol undergoes an acid-catalyzed dehydration to provide a small concentration of acrolein that is the reactive species. If acrolein itself is used as a reactant, it would polymerize. Crotonaldehyde is the reactive intermediate in the Doebner-von Miller synthesis (28). 

Doebner-von Miller synthesis, 2, 466 hydrazination, 2, 238 NMR, 2, 120 Quinoline, 5-methyl-nitration, 2, 50, 318 Quinoline, 6-methyl-mercuration, 2, 321 N-oxide... 

Quinoline, 2-(N-methylcarboxamido)-conformation, 2, 111 Quinoline, 2-methyl-1,2-dihydro-Doebner-von Miller synthesis, 2, 466 Quinoline, 2-methyl-2,4-diphenyl-1,2-dihydro-synthesis, 2, 476... 

Doebner-von Miller synthesis, 2, 466 synthesis, 2, 318 Quinoline, 3-pentyl-... 

Quinoline, 2,2,4-trimethyl-1,2-dihydro-antioxidant in polymers, 1, 395 Doebner-von Miller synthesis, 2, 468 Quinoline, trimethylstannyl-reactions, 2, 364 Quinoline, 4-vinyl-polymers, 1, 286... 

KNOEVENAGEL OOEBNER STOBBE Condensation Base catalyzed aldol condensation of aldehydes or ketones with an activated methylene group of a malonic ester (Knoevenagel Doebner) or a succinic ester (Stobbe)... 

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-... 

Phenolic resins were the first totally synthetic plastics invented. They were commercialized by 1910 [I]. Their history begins before the development of the structural theory of chemistry and even before Kekule had his famous dreams of snakes biting their tails. It commences with Gerhardt s 1853 observations of insoluble resin formation while dehydrating sodium salicylate [2]. These were followed by similar reports on the behavior of salicylic acid derivatives under a variety of reaction conditions by Schroder et al. (1869), Baeyer (1872), Velden (1877), Doebner (1896 and 1898), Speyer (1897) and Baekeland (1909-1912) [3-17]. Many of these early reports appear to involve the formation of phenolic polyesters rather than the phenol-aldehyde resins that we think of today. For... 

The Doebner reaction is a three component coupling of an aniline (1), pyruvic acid (2), and an aldehyde (3) to provide a 4-carboxyl quinoline (4). That product can be decarboxylated to furnish quinoline 5. 

In 1883, Bottinger described the reaction of aniline and pyruvic acid to yield a methylquinolinecarboxylic acid. He found that the compound decarboxylated and resulted in a methylquinoline, but made no effort to determine the position of either the carboxylic acid or methyl group. Four years later, Doebner established the first product as 2-methylquinoline-4-carboxylic acid (8) and the second product as 2- methylquinoline (9). Under the reaction conditions (refluxing ethanol), pyruvic acid partially decarboxylates to provide the required acetaldehyde in situ. By adding other aldehydes at the beginning of the reaction, Doebner found he was able to synthesize a variety of 2-substituted quinolines. While the Doebner reaction is most commonly associated with the preparation of 2-aryl quinolines, in this primary communication Doebner reported the successful use of several alkyl aldehydes in the quinoline synthesis. 

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