Friedel-Crafts acylation of anisole

The set of catalysts selected for the dehydration of 2-butanol was also tested for the Friedel-Crafts acylation of anisole [69, 70]. The catalytic test was performed in the liquid phase due to the high boiling points of the reactants and products of this reaction. Anisole was reacted with acetic anhydride at 120 °C in the absence of solvent. In principle, acylation can occur on both the ortho and para positions of anisole. The main product (>99%) over all catalysts in this study was para-methoxyacetophenone, indicating that the reaction predominantly takes place inside the zeolite micropores. The same trend in catalytic activity as in the 2-buta-nol dehydration reaction is observed the conversion of anisole into para-nicihoxy-acetophenone increases upon increasing Ge content of the catalyst (Fig. 9.17) [67]. The main cause of deactivation for this reaction is accumulation of the reaction products inside the micropores of the zeolite. The different behavior of Ge-ZSM-5, compared with ZSM-5, may therefore be due to improved diffusional properties of the former, as the presence of additional meso- and macropores allows for... 

Several metal triflate salts have been tested in the Friedel-Crafts acylation of anisole with benzoyl chloride in [C4Ciim][BF4]. At a reaction temperature of 80°C and catalyst loadings of 10 mol%, all salts led to 100% conversion with reaction rates decreasing in the order Cu(OTf)2 > Zn(OTf)2 > Sn(OTf)2 Sc(OTf)3, see Scheme 9.22.[92]... 

Selvin, R., Sivasankar, B., Rengaraj, K. Kinetic studies on Friedel-Crafts acylation of anisole by clayzic. React. Kinet. Catal. Lett. 1999, 67, 319-324. 

Table 2.9 Comparison of the Friedel-Crafts acylation of anisole using AICI3 (liquid phase) and H-Beta (heterogeneous).

To start our investigations, we examined the conversion of 2,3-dimethyl-2-butene (1) into 3,3,4-trimethyl-4-penten-2-one (2) as a model reaction (eq. 1). The choice of acetic anhydride as the acetylating agent was made in the light of related studies on the acylation of aryl ethers. Our work in this field had shown that acetic anhydride was the most effective reagent for the Friedel-Crafts acylation of anisole in the presence of Hp zeolite. A lower degree of conversion was achieved with acetyl chloride, while hardly any reaction occurred with ethyl acetate or acetic acid [6]. 

Ytterbium nonafluorobutylsulfonylimide complex Yb[N(S02C4F9)2]3 (10% mol) is employed in the Friedel-Crafts acylation of anisole with AAN. The reaction is performed in benzotrifluoride at 40°C for 2 h, affording quantitative yield of the C-acylation product. °... 

H. M. C. 2004. Friedel-Crafts acylation of anisole with acetic anhydride over silica-supported heteropolyphosphotungstic acid (HPW/SiOj). /. Mol. Catal. A Chem. 209 189-197. 

Friedel-Crafts acylation of anisole with benzoyl chloride (2 moles) by their addition together to a solution of anhydrous (5 mol%) cobait ll) chloride in dry methyl cyanide afforded a 72% yield of 4-methoxybenzophenone (ref. 126). 

For example, the Friedel-Crafts-acylation of anisole with acetic anhydride with the acidic zeolite H-beta leads to p-methoxyacetophenone in fixed-bed operation (Eq. 8-26). Compared with the traditional process, using more than one equivalent of AICI3 (Eq. 8-27), the number of unit operations could be reduced from 12 to 2 by Rhone-Poulenc. 

Preparation by demethylation of 3,5-difluoro-4 -methoxy-benzophenone (SM) with 48% hydro-bromic acid in refluxing acetic acid for 4 h (91%) [905,906]. SM was obtained by Friedel-Crafts acylation of anisole with 3,5-di-fluorobenzoyl chloride in ethylene dichloride in the presence of aluminium chloride at r.t. under nitrogen for 3 h (88%) [905]. 

Obtained by saponification of 3-acetoxy-4 -methoxy-benzophenone with 2 N sodium hydroxide in refluxing dilute ethanol for 30 min (98%). The starting material was obtained by Friedel-Crafts acylation of anisole with m-acetoxybenzoyl chloride in the presence of aluminium chloride in carbon disulfide at 5° for 20 h (15%) [990]. 

Obtained by Friedel-Crafts acylation of anisole with 4-nitrobenzoyl chloride and subsequent nitration of the obtained ketone [1649]. 

D. Baudry-Barbier studied the catalytic properties of Sc, La and Nd modified KIO clays in Friedel-Crafts acylations of anisole with benzoyl chloride for yielding 4-methoxybenzophenone, and found La modified KIO clay exhibited the best catalytic activity for acylations of anisole. In comparison with the acid catalyzed reactions using liquid acids, the solid acid catalyzed process was non-polluting and also the final work-up didn t require any aqueous treatment, which exhibited wide prospect for the clean synthesis of building block and fine chemicals [195]. 

The synthesis of estrone from anisole and glutaric anhydride was first described by Johnson and coworkers [225, 563, 564] in 1951 and was perfected by Kipriyanov and Kutsenko [565] in 1961 (yields and reagents in Scheme 46 are given in accordance with [565]). The Friedel—Crafts acylation of anisole (82) with glutaric anhydride and subsequent esterification led to the keto ester (474) which was converted by the Stobbe reaction into a mixture of tricarboxylic acids isomeric with respect to the position of the... 

---