Über die Kostanecki‐Robinson‐Reaktion von 2‐Hydroxy‐ω‐formylacetophenon

Abstract

Die bei der Darstellung von 3-Acetylchromon(4) durch Reaktion von 2-Hydroxy-w-formylacetophenon(1) mit Acetanhydrid/Natriumacetat (Kostanecki-Robinson-Reaktion) gefundenen Zwischenprodukte wurden als Acylal 2 bzw. Enolacetat 3 formuliert. 3 kann auch mit warig-alkoholischer Natronlauge in 4 umgewandelt werden. On the Kostanecki-Robinson-Reaction from 2-Hydroxy-w-formy lacetophenoneThe intermediary products found during the preparation of 3-acetylchromone (4) by the reaction of 2-hydroxy-a-formylacetophenone (1) with acetic anhydride/sodium acetate (Kostanecki-Robinson-Reaction) were described as acylal2 and enolacetate 3. With alcoholic-aqueous alkali 3 can be converted into 4.Wie wir vor einiger Zeit beschrieben haben, reagiert 2-Hydroxy-w-formylacetophenon (1) mit Acetanhydrid/Natriumacetat zum 3-Acetylchromon (4); ein Nebenprodukt wurde als Enolester 3 formuliert2).binson-Reaktion Trans-Enolester als Zwischenprodukte auftreten konnen3i4). Diese lassen sich in waBrigen und nichtwahigen Ldsungmitteln in Gegenwart von Basen zu Chromonen cyclisieren415).konstanten von 12 Hz fur eine Trans-Anordnung. Wir haben deshalb untersucht, o b die Bildung von 4 uber 3 verlauft, ob also 3 als Zwischenprodukt bei der Umsetzung von 1 nach Kostanecki-Robinson auftreten kann.

3-(Polyhaloacyl)chromones and their Hetero Analogues: Synthesis and Reactions with Amines

“…Compounds 2 were obtained in good yields without the formation of any side products arising from Michael-type additions onto the C=C bond of the pyrone moiety or dehydration of the starting chromanones 1 to 2-(polyfluoroalkyl)chromones. However, in marked contrast to the 3-formyl-and 3-acetylchromones, [2][3][4][5] the chromones obtained in this work were prone to facile and reversible covalent hydrate formation as observed from their 1 H and 19 F NMR spectra, which contained two sets of signals. The diagnostic signal for H-2 in chromones 2, which appeared at 8.5-8.7 ppm, was shifted upfield in hydrates 3 (8.3-8.4 ppm).…”

“…1 Chromones unsubstituted at C-2 and with 3-formyl or 3acetyl groups were first prepared in low yields from 3-(2hydroxyphenyl)-3-oxopropanal and 1-(2-hydroxyphenyl)butane-1,3-dione with ethyl orthoformate and acetic anhydride. 2 The synthesis of 3-acetylchromone has also been achieved by acetylation of 3-(2-hydroxyphenyl)-3oxopropanal with acetic anhydride/sodium acetate 2,3 and formylation of 1-(2-hydroxyphenyl)butane-1,3-dione with acetic formic anhydride/sodium formate 4a and dimethylformamide dimethyl acetal. 4b In 1973, a convenient synthesis of 3-formylchromone from 2-hydroxyacetophenone and the Vilsmeier reagent was reported.…”

A Novel and Convenient Synthesis of 3-(Polyhaloacyl)chromones Using Diethoxymethyl Acetate

“…1 Chromones unsubstituted at C-2 and with 3-formyl or 3acetyl groups were first prepared in low yields from 3-(2hydroxyphenyl)-3-oxopropanal and 1-(2-hydroxyphenyl)butane-1,3-dione with ethyl orthoformate and acetic anhydride. 2 The synthesis of 3-acetylchromone has also been achieved by acetylation of 3-(2-hydroxyphenyl)-3oxopropanal with acetic anhydride/sodium acetate 2,3 and formylation of 1-(2-hydroxyphenyl)butane-1,3-dione with acetic formic anhydride/sodium formate 4a and dimethylformamide dimethyl acetal. 4b In 1973, a convenient synthesis of 3-formylchromone from 2-hydroxyacetophenone and Vilsmeier reagent was reported.…”

“…Compounds 2 were obtained in good yields without the formation of any side products arising from Michael-type additions onto the C=C bond of the pyrone moiety or dehydration of the starting chromanones 1 to 2-(polyhaloalkyl)chromones. However, in marked contrast to the 3-formyl-and 3-acetylchromones, [2][3][4][5]…”