Reaction with aluminium chloride

Dichloromethane gives rise to very dangerous reactions with aluminium chloride ... 

When benzene is alkylated, it reacts with a haloalkane in the presence of aluminium chloride as a catalyst. In the example shown, chloromethane is used and the electrophile CH is generated from its reaction with aluminium chloride ... 

Regioselective reductive openings of mixed phenolic-benzylic cyclic acetals, using BH3-NMe3-AlCl3, under mild conditions to yield a benzylic ether and free the phenol group have been attributed to association of boron with the more basic oxygen (benzylic) followed by reaction with aluminium chloride.309... 

Condensation reactions with aluminium chloride as catalyst also involve the formation of intermediate complex compounds which have been isolated in some cases. These will be taken up in detail in Chapter VII. 

A colourless solid, CeHsCOCeHs, m.p. 49°C. It has a characteristic smell and is used in making perfumes. It is made from benzene and benzojd chloride using the Friedel-Crafts reaction with aluminium chloride as catalyst. 

Preparation by reaction of benzoyl chloride with m-cresol in the presence of aluminium chloride or titanium tetrachloride in nitrobenzene at 60° for 18 h (67% and 61% yields, respectively) [54]. The same reaction with aluminium chloride without solvent at 75° gave a 10% yield [144]. 

When lithium hydride is allowed to react with aluminium chloride in ether solution, two reactions occur ... 

The order of reaction with respect to aluminium chloride was ill-defined. Since nitrobenzene and aluminium chloride form a 1 1 complex which exhibits the simple monomeric molecular weight in nitrobenzene solution185, and since even in solutions of aluminium chloride and benzoyl chloride in nitrobenzene the aluminium chloride is preferentially associated with the solvent184, then in nitrobenzene solutions of aluminium chloride and benzenesulphonyl chloride the lesser basicity of the latter relative to benzoyl chloride means that the aluminium chloride must be mainly associated with nitrobenzene and in equilibrium with aluminium chloride associated with the sulphonyl chloride184. By analogy with... 

Using 1,2-dichloroethane as solvent, Brown et al. 16 have also studied the acetylation reaction, with acetyl chloride and aluminium chloride as reagents at 25 °C. The appropriate data for benzene are given in Table 111 and by comparison with Table 109 it appears that acetylation occurs some 300 times as fast as benzoylation. 

The acetylation reaction has been used by a number of workers for this purpose. Using acetyl chloride with aluminium chloride as catalyst in carbon disulphide or... 

For example /-butyl phenyl ether with aluminium chloride forms para-t-butyl phenol155. Often the de-alkylated phenol is also formed in considerable quantity. The reaction formally resembles the Fries and Claisen rearrangements. Like the Fries rearrangement the question of inter- or intramolecularity has not been settled, although may experiments based on cross-over studies156, the use of optically active ethers157 and comparison with product distribution from Friedel-Crafts alkylation of phenols158 have been carried out with this purpose in view. 

A new route to the tetrahydroTTF system is provided by reaction of oxalyl chloride with ethanedithiol followed by dehydration to give 35. When this is treated with aluminium chloride the salt 36 is formed and its X-ray structure is reported <00ZN(B)597>. The preparation of new simple benzoditelluroles 37 has been described <00MI1127>. Treatment of allyl dithiocarbamates 38 with bromine affords the 2-amino-l,3-dithiolanylium salts 39 <97MIP112282, 98MIP113243>. 

An alternative route to pyranthrone, involving baking 1,6-dibenzoylpyrene (6.96) with aluminium chloride, was also devised by Scholl (Scheme 6.18). The Scholl reaction is a key step in the synthesis of several polycyclic quinones the cyclisation of 1-benzoylnaphthalene to give benzanthrone (6.73) has already been mentioned. The mechanism of this cyclodehydrogenation reaction may involve an initial protonation step, if traces of water are present, or complexation with aluminium chloride. Electrophilic substitution is thereby... 

A ubiquitous co-catalyst is water. This can be effective in extremely small quantities, as was first shown by Evans and Meadows [18] for the polymerisation of isobutene by boron fluoride at low temperatures, although they could give no quantitative estimate of the amount of water required to co-catalyse this reaction. Later [11, 13] it was shown that in methylene dichloride solution at temperatures below about -60° a few micromoles of water are sufficient to polymerise completely some decimoles of isobutene in the presence of millimolar quantities of titanium tetrachloride. With stannic chloride at -78° the maximum reaction rate is obtained with quantities of water equivalent to that of stannic chloride [31]. As far as aluminium chloride is concerned, there is no rigorous proof that it does require a co-catalyst in order to polymerise isobutene. However, the need for a co-catalyst in isomerisations and alkylations catalysed by aluminium bromide (which is more active than the chloride) has been proved [34-37], so that there is little doubt that even the polymerisations carried out by Kennedy and Thomas with aluminium chloride (see Section 5, iii, (a)) under fairly rigorous conditions depended critically on the presence of a co-catalyst - though whether this was water, or hydrogen chloride, or some other substance, cannot be decided at present. 

As well as chlorination, benzene can undergo bromination when bromine is used as the reagent along with aluminium chloride or iron(lll) chloride as catalyst. The electrophiles, Ch and BrC are generated by the reaction between the halogen and the catalyst ... 

Aniline does not undergo Frledel-Crafts reaction (alkylation and acetylation) due to salt formation with aluminium chloride, the Lewis acid, which Is used as a catalyst. Due to this, nitrogen of aniline acquires positive charge and hence acts as a strong deactivating group for further reaction. 

General procedure for the cyclization of f-(aryltelluro)propenoyl chlorides with aluminium chloride The propenoyl chloride derivatives were dissolved in methylene chloride (1 g, 10 mL) under a nitrogen atmosphere. The solution was cooled to -78°C, and 1.1 equiv of aluminium chloride was added. The cooling bath was removed and the reaction was allowed to warm to room temperature. After stirring for 1 h at room temperature, the reaction mixture was poured into ice-water, and the products were extracted with several portions of methylene chloride. The combined methylene chloride extracts were dried over sodium sulphate and concentrated. The residues were recrystallized from methanol if NMR spectroscopy showed a single product. 

J.A. Norris and B.M. Sturgis, The preparation of nitriles and amides, Reactions of esters with acids and with aluminium chloride. J.Am.Chem.Soc., 61 (1939) 1413-14. 

Phenolic ketones may be prepared by the Hoesch acylation reaction, which may be regarded as an extension of the Gattermann aldehyde synthesis (Section 6.10.1, p. 990). The procedure involves reaction of a nitrile with a phenol (or phenolic ether) in the presence of zinc chloride and hydrogen chloride best results are usually obtained with polyhydric phenols or their ethers, as for example in the preparation of phloroacetophenone (Expt 6.125). The formation of phenolic ketones by means of the Fries rearrangement of phenolic esters with aluminium chloride is discussed on p. 976. 

One synthesis of this class is by reaction of a benzotrichloride with an aromatic substrate (usually employed in small excess as the solvent) with aluminium chloride as the nominal catalyst. Part way into the reaction, a second liquid phase separates, this is substantially ionic and permits accelerated reaction. At the same time, hydrogen chloride evolution will increase, often leading to pressurisation. Some examples also show crystallisation of the trityl tetrachloroaluminate, which may further encourage gas evolution. 

Compound 85 was dehydrogenated at 300° over palladium black under reduced pressure to a pyridine derivative 96 which was independently synthesized by the following route. Anisaldehyde (86) was treated with iodine monochloride in acetic acid to give the 3-iodo derivative 87. The Ullmann reaction of 87 in the presence of copper bronze afforded biphenyldialdehyde (88). The Knoevenagel condensation with malonic acid yielded the unsaturated diacid 91. The methyl ester (92) was also prepared alternatively by a condensation of 3-iodoanisaldehyde with malonic acid to give the iodo-cinnamic acid (89), followed by the Ullmann reaction of its methyl ester (90). The cinnamic diester was catalytically hydrogenated and reduced with lithium aluminium hydride to the diol 94. Reaction with phosphoryl chloride afforded an amorphous dichloro derivative (95) which was condensed with 2,6-lutidine in liquid ammonia in the presence of potassium amide to yield pyridine the derivative 96 in 27% yield (53). 

Initial reports leading to speculation about non-linear or branched polymeric connectivity were provided by researchers such as Zincke,121 who isolated an insoluble hydrocarbon-based material upon the treatment of benzyl chloride with copper. Later, in 1885, reaction of benzyl chloride with aluminium chloride led Friedel and Crafts131 to report similar observations. When benzyl chloride was subjected to the action of a zinc-copper couple analogous materials were obtained.141... 

For instance, the reaction of cis- and tra/w-2-butene oxide with aluminium chloride yields mainly erythro- and threo-chlorohydrin (after hydrolysis) respectively [66]. 

Fig (3) Trans annular oxidation of (17) yields epoxytriene (19) which is cleaved with acetyl p-toluensulphonate to give olefinic acetate (20) which is converted to (22) by hydrogenation, reduction, oxidation respectively. Its conversion to (23) is carried out by standard organic reactions described in Fig.(2). Demethylation of (23) with aluminium chloride, leads the formation of methyl pisiferate (3). 

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