By the Gatterman reaction

Scheme 6.89. A potential pathway for the formation of benzenecarbaldehyde (benzaldehyde CeHsCHO) by the Gatterman Reaction among benzene (C6H6), carbon monoxide (CO), hydrogen chloride (HCI), and aluminum chloride (AICI3) at high pressure. The process is formally similar to the Friedel-Crafts reaction.

In the early Gatterman s preparative chemistry book, " the one-pot synthesis of dUiydropyridine derivatives like those formed by the Hantzsch reaction was one of practical laboratory exercises. 

The Cu(I)/Cu(II) couple is utilised in the Sandmeyer reaction, in which an aromatic diazonium salt is converted into the corresponding aryl chloride by the catalytic action of Cu(I)Cl. There is a variation that uses copper and HC1, which is called the Gatterman reaction. 

C6H5N2 + Cl- C HjCl + N2 This reaction was discovered by the German chemist Traugott Sandmeyer (1854-1922) in 1884. A variation of the reaction, in which the catalyst is freshly precipitated copper powder, was reported in 1890 by the German chemist Ludwig Gatterman (1860-1920). This is known as the Gatterman reaction (or Gat-terman-Sandmeyer reaction). 

In this new strategy, methyl 3,5-dihydroxybenzoate was subjected to the Gatterman reaction and the resulting product was transformed by chloro-methylation into 90 (Scheme 17), which was found to be different from the phthalide prepared earlier and therefore suggested that the correct structure for the previously prepared phthalide was 89. 

Solution to 10a Benzaldehyde can be prepared by the Gatterman-Koch reaction (page 919) or by the following sequence of reactions ... 

Several name reactions are promoted by AICI3. For example, the Darzens-Nenitzescu reaction is simply the acylation of alkenes. The Ferrario reaction generates phenoxathiins from diphenyl ethers (eq 19) The rearrangement of acyloxy aromatic systems is known as the Fries rearrangement (eq 20). Aryl aldehydes are produced by the Gatterman aldehyde synthesis (eq 21). The initial step of the Haworth phenanthrene synthesis makes use of a Friedel-Crafts acylation. The acylation of phenolic cort tounds is called the Houben-Hoesch reaction (eq 22). The Leuckart amide s)oithesis generates aryl amides from isocyanates (eq 23). ... 

When unsubstituted, C-5 reacts with electrophilic reagents. Thus phosphorus pentachloride chlorinates the ring (36, 235). A hydroxy group in the 2-position activates the ring towards this reaction. 4-Methylthiazole does not react with bromine in chloroform (201, 236), whereas under the same conditions the 2-hydroxy analog reacts (55. 237-239. 557). Activation of C-5 works also for sulfonation (201. 236), nitration (201. 236. 237), Friede 1-Crafts reactions (201, 236, 237, 240-242), and acylation (243). However, iodination fails (201. 236). and the Gatterman or Reimer-Tieman reactions yield only small amounts of 4-methyl-5-carboxy-A-4-thiazoline-2-one. Recent kinetic investigations show that 2-thiazolones are nitrated via a free base mechanism. A 2-oxo substituent increases the rate of nitration at the 5-position by a factor of 9 log... 

Mesitaldehyde may be prepared from mesitylmagnesium bromide by the reaction with orthoformate esters3 or ethoxy-methyleneaniline 3 from acetylmesitylene by oxidation with potassium permanganate,4 from mesitoyl chloride by reduction,5 from mesityllithium by the reaction with iron pentacarbonyl and from mesitylene by treatment with formyl fluoride and boron trifluoride,7 by treatment with carbon monoxide, hydrogen chloride, and aluminum chloride,8 or by various applications of the Gatterman synthesis.9-11... 

The decarbonylation of aromatic aldehydes with sulfuric acid" is the reverse of the Gatterman-Koch reaction (11-16). It has been carried out with trialkyl- and trialkoxybenzaldehydes. The reaction takes place by the ordinary arenium ion mechanism the attacking species is H and the leaving group is HCO, which can lose a proton to give CO or combine with OH from the water solvent to give formic acid." Aromatic aldehydes have also been decarbonylated with basic catalysts." When basic catalysts are used, the mechanism is probably similar to the SeI process of 11-38. See also 14-39. 

Alternatively, chlorine or bromine can also be introduced in the benzene ring by treating the diazonlum salt solution with corresponding halogen acid in the presence of copper powder. This Is referred as Gatterman reaction. 

A useful method for the synthesis of 5-chloro-l,2,4-thiadiazoles (206) is the reaction of amidines with trichloromethylsulfenyl chloride (see Equation (30)). 3-Halo derivatives (349) (X = Cl, Br, I) (Equation (57)) have been obtained in moderate yields from the corresponding amines (348) via the Sandmeyer-Gatterman reaction <84CHEC-I(6)463>. 3-Chloro-l,2,4-thiadiazolin-5-ones (350) and (351) can be prepared by reacting chlorocarbonylsulfenyl chloride with carbodiimides or cyanamides respectively (Scheme 79) <84CHEC-I(6)463>. 

Arenes can be formylated by generating the active intermediate, CfeC—H, from reagents other than HCOCl. The Gatterman-Koch reaction uses a high-pressure gaseous mixture of CO and HCl. 

Introduction. The diazo group, N2X, is easily replaced by a number of other functional groups, such as OH, Cl, Br, I and CN. This affords a convenient method for the preparation of such derivatives as cannot be obtained by other methods except with great difficulty. The replacement of N2X by a halogen group is accomplished by heating the solution of diazonium salt with cuprous halide (Sandmeyer reaction) or with finely divided copper (Gatterman reaction). In the preparation of iodides the catalytic effect of copper is not required it is necessary only to pour the diazonium salt into a solution of potassium iodide and then to acidify the solution ... 

Gatterman amide synthesis The synthesis of an amide by the reaction between an aromatic molecule and carbamoyl chloride, H2NCOCl, in the presence of A1C13. 

The synthesis of benzaldehyde from benzene poses a problem because formyl chloride, the acyl halide required for the reaction, is unstable and cannot be purchased. Formyl chloride can be prepared, however, by means of the Gatterman-Koch formyla-tion reaction. This reaction uses a high-pressure mixture of carbon monoxide and HCl to generate formyl chloride, along with an aluminum chloride-cuprous chloride catalyst to carry out the acylation reaction. 

Closely related arylation to Pschorr reaction is the Gatterman synthesis of biaryls (II) which involves the coupling reaction of two aryldiazonium salts (III) by the influence of copper or copper(I) salts [97,98], Scheme 24. 

A particularly misleading situation can occur when a reaction product forms a complex with the catalytic material. Thus the Gatterman-Koch reaction of benzene and carbon monoxide to produce benzaldehyde is thermodynamically unfavourable, but reaction proceeds under pressure in the presence of at least 1 mole AlCls/mole benzene. However, the benzaldehyde-AICI3 complex formed must be cleaved chemically, with water for example, to liberate the product. Surprisingly, the similar conversion of toluene to p-tolualdehyde (p-methylbenzaldehyde) is favourable, and separation from the catalyst system can be achieved by simple distillation workers with Mitsubishi in Japan have used BFa/HF. ... 

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