Benzalacetophenone, preparation

Benzylacetophenone has been prepared by the reduction of benzalacetophenone with zinc and acetic acid1 and catalytic-ally with palladium and hydrogen 2 by the reduction of /3-duplo-benzylidene acetophenone monosulfide 3 by the oxidation of the corresponding car bind with chromic acid 4 by the hydrolysis of ethyl benzyl benzoylacetate 5 from acetophenone and benzyl chloride by the action of sodamide 6 and from benzoic and hydrocinnamic adds using as catalysts manganese oxide 7 and ferric oxide.8... 

Dibenzoylmcthane has been prepared by the hydrolysis of dibenzoyl acetic acid 1 by the slow spontaneous decomposition of acetyl dibenzoyl methane 2 by the action of metallic sodium,3 sodium ethylate,3 sodium methylate,4 alchoholic potash,4 or sodamide 5 on mixtures of acetophenone and ethyl benzoate and by the action of alcoholic potash,6 sodium methylate,7 or sodium ethylate 8 on benzalacetophenone dibromide. 

Thietanes can also be prepared by ring contraction of higher-membered heterocyclic rings. Thermolysis of the dithiolane dioxide 129 in benzene leads to trans-2-phenyl-3-benzoylthietane (130) and benzalacetophenone (Eq. 20). 

Reaction of l-aryl-3-carbethoxy-6-phenyl-l,4,5,6-tetrahydropyridazin-4-ones 718 with activated olefins such as benzalacetophenone, benzalacetone, 3-benzylideneacetylacetone, diethyl 2-benzylidenemalonate, and a-cyano-/3-phenylacrylic acid in the presence of an organic base like pyrrolidine, morpholine, piperidine, or triethylamine gave the corresponding 2,8-dihydro-l//-pyrano[2,3-t7 pyridazines 719-723, respectively. The 1-oxo- and 1-imino derivatives of the pyrano[2,3-r/ pyridazine ring system were also prepared from the respective 6-oxo or 6-imino derivative of the starting pyridazine 718 under the same conditions (Equation 60) <1989IJB733>. 

Sufficient alcohol is used to dissolve the benzaldehyde rapidly, as well as to retain the benzalacetone in solution until it has had time to react with the second molecule of aldehyde. Lower concentrations of base slow up the formation of the dibenzalacetone and thus favor side reactions which tend to yield a sticky product. Higher concentrations of base give added difficulty in washing. These concentrations were suggested by, and are approximately the same as, those used in the preparation of benzalacetophenone described in Org. Syn. 7, r. 

Only temperatures between 20 and 250 were tried, it being expected that a change of temperature would have the same effect as it does in the preparation of benzalacetophenone mentioned above. 

To the cold ethereal diazomethane solution prepared from 10 g of nitro-somethylurea (about 2.8 g CH2N2, 0.067 mol volume 100 ml) was added a solution of benzalacetophenone 1 (14.5 g, 0.07 mol) in 150 ml of ether (Scheme A.8). Within 5 min a precipitate formed. After 1 h at — 14°C filtration yielded 13.5 g of the colorless 3-benzoyl-4-phenyl-A1-pyrazoline 2. Partial evaporation of the ether gave an additional 3 g of the material. The total yield, based on 13.5 g of benzalacetophenone (0.065 mol), was 100%. The material may be crystallized from methyl or ethyl alcohol, a mixture of ethyl acetate and petroleum ether, a mixture of chloroform and petroleum ether, or carbon tetrachloride. The best results were obtained using methyl alcohol. Melting point 92-93°C. 

This difficulty may be overcome by partial neutralization with acetic acid. In this manner, a-phenyl-/3-benzoylpropionitrile has been prepared from benzalacetophenone and alcoholic potassium cyanide (96%). ... 

A) Preparation of Benzalacetophenone (Sm.). Place in an eight-inch tube a solution of 1 g of sodium hydroxide in 8 ml of water and 6 ml of alcohol. Cool in an ice-salt mixture. Add 2.6 g of acetophenone (2.6 ml) shake well, and immerse again in the cold bath. Add 2.3 g (2.2 ml) of freshly distilled pure benzaldehyde, close tube with a solid rubber stopper, and shake vigorously. Allow... 

There are relatively few reports involving the Michael addition of cyanomethylphosphonate anions to unsaturated compounds. The reaction provides a methodology for the elaboration of new reagents but more frequently is used for the preparation of phosphonylated heterocycles. Under basic conditions, diethyl cyanomethylphosphonate adds to benzalacetophenone and 2-bcnzylidcne-3-methyl-4-nitro-3-thiolene-l,l-dioxide to give the addition products in modest yields.- - - " ... 

Michael addition of l-(alkoxycarbonyl)methylphosphonate anions to unsaturated compounds provides a methodology for the elaboration of new reagents and also for the preparation of phosphonylated heterocycles. Thus, in the presence of basic catalysts, diethyl l-(ethoxycarbonyl)alkyl- and l-(ethoxycarbonyl)methylphosphonates add to a.p-nnsaturatcd esters and nitriles.Addition of diethyl l-(ethoxycarbonyl)methylphosphonates under basic conditions to methyl or ethyl acrylates, acrylonitrile, and benzalacetophenone occurs readily and gives rise to products of addition to one and two molecules of the unsaturated compound (Scheme 8.14). ° - ° Reaction of a-substituted phosphonoacetates with acrylates is less vigorous, and attempts at addition to crotonic and methacrylic esters fail. mi-zos-zos... 

Poly(4 -vinyl-fraws-benzalacetophenone) was prepared by Unruh 52> by condensation of poly(p-vinyhcetophenone) with benzaldehyde. In his studies Unruh s2> compared the photochemical behavior of poly(4 -vinyl-fraMS-benzalacetophenone) with that of the model compound, 4-ethylbenzalacetophenone. Both the polymer and its model showed typical photoisomerization behavior when irradiated in dilute solution. This behavior of the two species was consistent with the results reported for benzalacetophenone by Lutz, et al. 53<54>. Unruh found, however, that when the trans polymer was photoisomerized to the cis form, the expected complete return to trans form upon addition of acid failed to result. This fatigue or loss was attributed to small amounts of intrachain... 

Diphenylpropiophenone has been prepared from ben-zalacetophenone and phenylmagnesium bromide,1 by the condensation of benzalacetophenone and benzene with concentrated sulfuric acid 2 or with aluminum chloride,3 and by the action of aluminum chloride on a mixture of benzene and the hydrochloride of benzalacetophenone.3 The procedure described here is essentially that of Vorlander and Friedberg.3... 

The Aldol Condensation Reaction Preparation of Benzalacetophenones (Chalcones)... 

In this experiment, procedures are given for preparing benzalacetophenones (chalcones). You should choose one of the substituted benzaldehydes and react it with the ketone, acetophenone. All the products are solids that can be recrystallized easily. 

Benzalacetophenones (chalcones) are prepared by the reaction of a substituted benzaldehyde with acetophenone in aqueous base. Piperonaldehyde, p-anisaldehyde, and 3-nitrobenzaldehyde are used. 

Give a mechanism for the preparation of the appropriate benzalacetophenone using the aldehyde and ketone that you selected in this experiment. 

In Experiment 37, you were introduced to the aldol condensation reaction, which you used to prepare a variety of benzalacetophenones or chalcones. In this experiment, you will again prepare chalcones, but you will do so in a guided-inquiry experiment that simulates some of the methodology that you are likely to use in research. 

You will select from a variety of substituted benzaldehydes (1) and substituted acetophenones (2) to prepare benzalacetophenones (chalcones) (3) that bear a combination of substituents in each of the aromatic rings (see figure). 

In Experiment 37 ("The Aldol Condensation Reaction Preparation of Benzalacetophenones"), substituted benzaldehydes are reacted with acetophenone in a crossed aldol condensation to prepare benzalacetophenones (chalcones). This is illustrated in the following reaction, where Ar and Ph are used as abbreviations for a substituted benzene ring and the phenyl group, respectively. ... 

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