Acetophenone Friedel-Crafts reaction

TTie true ketones, in which the >CO group is in the side chain, the most common examples being acetophenone or methyl phenyl ketone, C HjCOCH, and benzophenone or diphenyl ketone, C HjCOC(Hj. These ketones are usually prepared by a modification of the Friedel-Crafts reaction, an aromatic hydrocarbon being treated with an acyl chloride (either aliphatic or aromatic) in the presence of aluminium chloride. Thus benzene reacts with acetyl chloride... 

Acetic anhydride can be used to synthesize methyl ketones in Friedel-Crafts reactions. For example, benzene [71-43-2] can be acetylated to furnish acetophenone [98-86-2]. Ketones can be converted to their enol acetates and aldehydes to their alkyUdene diacetates. Acetaldehyde reacts with acetic anhydride to yield ethyhdene diacetate [542-10-9] (18) ... 

Acetophenone. Acetophenone [98-86-2] (methyl phenyl ketone) is a colorless Hquid that forms laminar crystals at low temperature (mp 20°C). It has a characteristic sweet orange blossom odor, and is soluble in alcohols and ethers. It is found in nature in oil of casatoreum, obtained from beavers oil of labdanum, recovered from plants and in buds of balsam poplar. It can be prepared by the Friedel-Crafts reaction (qv) of acetyl chloride with benzene in the presence of aluminum chloride however, this route is of Htde commercial significance. 

The aluminum trihalides are particularly important Lewis acids in the chemical industry. They promote or catalyze a large variety of reactions. One of the most important applications is the Friedel-Crafts reaction, in which two molecules combine, forming a new C—C bond. For example, aluminum chloride or some other Lewis acid catalyzes the reaction between an acid chloride and benzene to form acetophenone ... 

Antimony pentachloride is a reactive Lewis acid that can be used for Friedel-Crafts reactions and some other Lewis-acid-catalyzed reactions. The HF-SbF5 system is known as magic acid, and carbocations are stabilized in this medium.353 By using the HF-SbF5 system, alkylation of acetophenone (a relatively unreactive aromatic compound) has been achieved (Scheme 87). 

This yield of acetophenone is 10% better than that obtained in the ordinary Friedel-Crafts reaction. A similar method can be applied to the preparation of p-tolyl-methyl-ketone, 20 gms. (1 mol.) of dry toluene, 2 gms. of aluminium powder, 35 gms. of mercuric chloride, and 17 gms. (1 msl.) of acetyl chloride being used. The yield is 45% theoretical (13 gms.). The ketone is obtained as a low-melting solid, B.P. 224°. 

We used this strategy in chapter 6 under two-group C-X disconnections where bromination of ketones was the usual functionalisation. More relevant here are conversions of carbonyl compounds into 1,2-dicarbonyl compounds by reaction with selenium dioxide SeC>2 or by nitrosation. So acetophenone 57 gives the ketoaldehyde10 58 with SeC>2. These 1,2-dicarbonyl compounds are unstable but the crystalline hydrate 59 is stable and 58 can be reformed on heating. Since aromatic ketones such as 57 would certainly be made by a Friedel-Crafts reaction the disconnection 58a is not between the two carbonyl groups and offers an alternative strategy. 

The method is especially valuable for the preparation of certain substituted acetophenones, namely, o- and p-nitroacetophenone and o-chloro-acetophenone. Methods involving Grignard, Friedel-Crafts, or nitration reactions are apparently not applicable for the preparation of these nitro compounds, and the Friedel-Crafts reaction is not applicable to the preparation of o-chloroacetophenone. Although the acetoacetic ester synthesis has been used for the preparation of these and other substituted acetophenones, it may be complicated by O-acylation and also by cleavage at either acyl group (cf. method 212). 

Friedel-Crafts reaction of arenes with a-chloro-a-(methylthio)acetophenones [19], When A -phenylbenzimidoyl chlorides are aroylated with an aryl halide in the presence of a catalytic amount of an azoliuni salt (such as 1,3-dimethylimidazolium iodide) and sodium hydride, followed by acid treatment in TUF, unsymmetrical benzils can be isolated in 80-92% yields [201. Added to this method is the sequence ketone enaminoketone a-diketone, which cleaves a carbon-carbon double bond in the final stage by photooxygenation [21]. 

Ref 5). Insol in w but miscible with all common org solvents. According to Kirk Othmer(Ref 2), it was first prepd in 1857 by Friedel by distn of a mizt of Ca benzoate and Ca acetate. Commercially,acetophenone is prepxl by the Friedel—Crafts reaction usr ing benz,Al chloride and acetic anhydride. 

Friedel-Crafts reaction. A type of reaction involving anhydrous aluminum chloride and similar metallic halides as catalysts, discovered in 1877 by Charles Friedel, a French chemist (1832-1899), and James Mason Crafts, an American chemist (1830-1917), during joint research in France it has been developed since then for many important industrial uses, exemplified by the condensation of ethyl chloride and benzene to form ethylbenzene and the manufacture of acetophenone from acetyl chloride and benzene. The name is now applied to a wide variety of acid-catalyzed organic reactions. 

Fifty years ago, Simons et al. synthesized trifluoroacetophenone for the first time (eqn. 1, refs. 1,2). Since then, the trifluoroacetylation of aromatic compounds has continuously attracted the interest of chemists (refs. 3-16). Indeed, the classic Friedel-Crafts reaction (refs. 1,2) requires sub-stoichiometric quantities of aluminium chloride and trifluoroacetylchloride whose boiling point, - 27 °C, makes it difficult to use. Moreover, some F/Cl exchange between trifluoro-acetophenone... 

The ketones are readily prepared, for example, acetophenone from benzene, acetyl chloride (or acetic anhydride) and aluminium chloride by the Friedel and Crafts reaction ethyl benzyl ketones by passing a mixture of phenylacetic acid and propionic acid over thoria at 450° and n-propyl- p-phenylethylketone by circulating a mixture of hydrocinnamic acid and n-butyric acid over thoria (for further details, see under Aromatic Ketones, Sections IV,136, IV,137 and IV,141). 

Friedel-Crafts Acylation. The Friedel-Crafts acylation procedure is the most important method for preparing aromatic ketones and thein derivatives. Acetyl chloride (acetic anhydride) reacts with benzene ia the presence of aluminum chloride or acid catalysts to produce acetophenone [98-86-2], CgHgO (1-phenylethanone). Benzene can also be condensed with dicarboxyHc acid anhydrides to yield benzoyl derivatives of carboxyHc acids. These benzoyl derivatives are often used for constmcting polycycHc molecules (Haworth reaction). For example, benzene reacts with succinic anhydride ia the presence of aluminum chloride to produce P-benzoylpropionic acid [2051-95-8] which is converted iato a-tetralone [529-34-0] (30). 

The course of the reaction may involve either the acylation of the ketone to a -diketonic intermediate following thereupon the pathway in Section II, C, 2, a, or alternatively the condensation of two moles of ketone to yield an intermediate dypnone which then undergoes acylation following the pathway in Section II,C, l,a. Dilthey and Fischer thought the first alternative more plausible, on the basis of reaction yields, and this lead them to explore the pathway in Section II,C,2,a. Schneider and Ross and Diels and Alder believed that the second alternative operates. Both views are plausible since acylations of methyl ketones to S-diketones are known to take place in the conditions of this reaction, and dypnone ha.s been isolated from acetophenone on treatment with Friedel-Crafts catalysts, in the absence of an acid anhydride or chloride (an excess of catalyst... 

Another recent patent (22) and related patent application (31) cover incorporation and use of many active metals into Si-TUD-1. Some active materials were incorporated simultaneously (e.g., NiW, NiMo, and Ga/Zn/Sn). The various catalysts have been used for many organic reactions [TUD-1 variants are shown in brackets] Alkylation of naphthalene with 1-hexadecene [Al-Si] Friedel-Crafts benzylation of benzene [Fe-Si, Ga-Si, Sn-Si and Ti-Si, see apphcation 2 above] oligomerization of 1-decene [Al-Si] selective oxidation of ethylbenzene to acetophenone [Cr-Si, Mo-Si] and selective oxidation of cyclohexanol to cyclohexanone [Mo-Si], A dehydrogenation process (32) has been described using an immobilized pincer catalyst on a TUD-1 substrate. Previously these catalysts were homogeneous, which often caused problems in separation and recycle. Several other reactions were described, including acylation, hydrogenation, and ammoxidation. 

---