Kostanecki

Kojic acid — see also Pyran-4-one, 5-hydroxy-2-hydroxymethyl-, 3, 611 acylation, 3, 697 application, 3, 880 occurrence, 3, 692 reactions, 3, 714, 715 with amines, 3, 700 with phenylhydrazine, 3, 700 synthesis, 3, 810 Kokusagine occurrence, 4, 989 Kokusaginine occurrence, 4, 989 synthesis, 4, 990 Koopmans theorem, 2, 135 Kostanecki-Robinson reaction chromone and coumarin formation in, 3, 819-821 mechanism, 3, 820 flavones, 3, 819... 

ROBINSON - ALLAN - KOSTANECKI Chromone Synthesis Synthesis of chromones or coumannes from o acyioxy aromatic ketones... 

The conversion of c>-hydroxyaryl ketones la to chromones 2a and/or coumarins 3a with aliphatic acid anhydrides in the presence of the sodium or potassium salt of the corresponding acid and the reaction between lb and aromatic acid anhydrides and the salt of the corresponding acid to form flavones 2b (Allan-Robinson) is called the Kostanecki-Robinson (K-R) reaction. ... 

Although the literature refers to the formation of chromones/coumarins as the Kostanecki reaction (and often the Kostanecki-Robinson reaction) and the synthesis of flavones as the Allan-Robinson reaction, others have chosen to merge the two reactions and refer to both transformations as the Kostanecki-Robinson reaction. This section will follow the latter school of thought, and use the Kostanecki-Robinson (K-R) nomenclature. 

Over the years the literature is filled with examples where the initial characterization was incorrect. One example is illustrated below. In 1940, Sethna and Shah presumed that they synthesized coumarins 42 and 43 from a reaction between P-orcacetophenone (44) and its 4-0-methyl ether 45 under standard Kostanecki-Robinson conditions, respectively. Three decades later Bose and Shah synthesized coumarin 43 via another route and concluded that the initial assignment made by Sethna and Shah was incorrect. After the Bose and Shah findings were published, Ahluwalia and Kumar concluded that the Sethna and Shah products were actually chromones 46 and 47 based on proton NMR data and chemical derivatization. Despite these shortcomings, the Kostanecki-Robinson reaction remains an effective method for formation of both coumarins and chromones. 

R] (a) Hauser, C. R. Swamer, F. W. Adams, J. T. Org. React. 1954, 8, 59. [R] (b) Ellis, G. P., Chromenes, Chromanones, and Chromones from The Chemistry of Hetereocylic Compounds, Weissberger, A. and Taylor, E. C., eds John Wiley Sons, 1977, vol. 31, New York, p.495. Note The author in the former reference refers to the formation of chromones, coumarins, and flavones as the Kostanecki acylation while the latter author calls the formation of chromones and coumarins the Kostanecki-Robinson reaction. 

The first chemists to prepare a monocyclic pyrylium salt were von Kostanecki and Rossbach who in 189 6 described the fluorescence in dilute aqueous solution of the reaction product obtained from l,3,5-triphenjdpontane-l,5-dione (benzylidene-diacetophenone) and sulfuric acid. However, they failed to isolate the compound which caused the fluorescence and did not suspect that it was a pyrylium salt. It was only in 1916-1917 that Dilthey recognized that this fluorescence resulted from 2,4,6-triphenylpyrylium (3). 

Condensation of 2,4-dihydroxypropiophenone (172) with benzoyl chloride and sodium benzoate goes to afford chromone 174, probably via ester 173. This procedure is known as the Kostanecki-Robinson reaction Methylation (175) of the remaining phenolic function by means of dimethyl sulfate, followed by reaction... 

This method1 of preparing j3-resorcylic acid is a modification of the method given by Bistrzycki and Kostanecki.2... 

The history of BONA pigment lakes parallels that of (J-naphthol pigment lakes. Literary evidence of the use of 2-hydroxy-3-naphthoic acid, which was first synthesized in 1887 by Schmitt and Burkard as a coupling component, dates from 1893 (Kostanecki). However, it was not until 1902 that the compound began to be employed in dye synthesis by AGFA (aniline - BONA). 

Also known as Kostanecki-Robinson reaction. Transformation 1 2 represents an Allan—Robinson reaction (see page 8), whereas 1 3 is a Kostanecki (acylation) reaction ... 

Limberakis, C. Kostanecki-Robinson Reaction In Name Reactions in Heterocyclic Chemistry, Li, J. J. Corey, E. J., Eds. Wiley Sons Hoboken, NJ, 2005, 521—535. (Review). 

V. Synthesis of 5,7,4 -Trihydroxyflavone by v. Kostanecki and the Establishment of Its Identity with Natural Apigenin. 62... 

Diosmetin. After v. Kostanecki and coworkers isolated true apigenin from crude apigenin and proved its identity with the syn-... 

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