The residue from the first distillation was diluted with were by Galbraith Laboratories, Inc., Klloxville, water to give 6.88 g of solid which yielded 5.63 g (81 %) of T~~~~~~ triphenylphosphine oxide and 0.79 g (I1 % recovery) of crude triphenylphosphine, both of which were identified by comparison of their ~nfrared spectra nlth those of 1, A, W, F~~~~. J. erg, @hem. 30, 3663 (1965 A number of new n~troll~droxychalcones are reported. Electron-donat~ng groups in the aldehyde fakor condensation by HCI, and e l c c t r o n -~~~t h d l a \~~n g substituents fa\or condensation by haOH.C a n a d a n Journal of Chernistr\ 47, 1254Chernistr\ 47, (1969 A number of chalcones have been synthesized from acetophenones and benzaldehydes and the yields compared. Table I lists the results of condensations carried out in the presence of NaOH. The substituents in the aldehyde component increase the yield of chalcone formation in aqueous ethanol in the f o l l o~i n g way: Table I1 records the results of experiments carried out in ethanol in the presence of HCl. The order of effectiveness of reactants nith substituents other than orrho call be established as follows :and for ortho substituents:The yields show a rough parallelism with Hammett's substituents constants (I), and with basicities (pK,,+) (2). These results are in accordance with earlier observations (3-5). It can be concluded that electron-donating substitue~lts favor condensation by acid catalysts and that electron-withdrawing groups favor condensation by bases. The choice of condensing agent for the synthesis of chalcones can generally be decided on this basis. ExperimentalAldehydes and acetophenones were obtained from Aldrich Cheiuical Co. Inc.; Coluinbia Organic Chemical Co. ; and from Distillation Products. After having checked their purity most of them were used without further purification. Nitrohydroxyacetophenones were prepared as described earlier (4). Syntheses of chalcones in the presence of NaOH were the saine as previously reported (4). The acidic condensation was carried out as follo\vs.An ethanolic solution of the appropriate acetophenone 2,4-di0Me 2 2-oMe > > 2,3-di0Me = &5-dioMe and aldellyde %as kept ice-cold while being saturated withHC1 gas for 30 min.

SUMMARYA number of new nitrohydroxychalcones have been synthesized using sodium hydroxide and hydrogen chloride as catalysts. I t has been found that with substituents which increase the acidity of acetophenones or the electrophilic character of benzaldehydes (e.g. NOn, halogen, CN), sodium hydroxide is the better condensing agent, while with those substituents which increase the basic strength of the carbonyl, hydrogen chloride is satisfactory.

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.

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