Acetamidation electrochemical

We like to conclude the section with the spectacular molecular structure of the octanuclear platinum acetamidate blue [Pt8(NH3)16 (CH3CONH)8]10+, Figure 2, even if no pertinent electrochemical investigation has been carried out.25... 

For example, acetyladamantane and isopropyl methyl ketone gave 1-adamantyl-acetamide in 85% yield and N-acetyl-isopropylamine in 46% yield, respectively [79]. A similar a-cleavage was observed in the electrochemical oxidation of the a-branched cyclic ketone (43) using Et3N-5HF as an electrolyte (Scheme 16) [81]. 

In acetonitrile, carbonium ions combine with the solvent to form a nitrillium ion. The latter reacts with added water to form the N-substituted acetamide, often in good yield [5, 6, 7]. Thus electrochemical oxidation of alkanes in acetonitrile is a route for the introduction of an amino-substituent. Some carbonium ions are inefficiently quenched by acetonitrile and eliminate a proton to form an alkene. This alkene is readily oxidised at the anode potentials used and oxidation products contribute to electrode fouling. Pulsing of the anode potential to +0.3 V vs, see helps to... 

Various side reactions are possible. The solvent acetonitrile can also react as a nucleophilic agent to form, after hydrolysis, acetamides [R CH(NHAc)R2].23 Methanol as solvent results in a methoxylation product [R CH(OMe)R2].22 The selectivity of partial electrochemical fluo-rination depends on many different parameters, e.g. the type of solvent, the supporting electrolytes, the electrode materials, the electrochemical potential etc. The electrochemical potential can be measured by cyclic voltametry. Partially fluorinated compounds are particularly used in medical fields or as pesticides. 

The solvents used for electroanalytical determinations vary widely in their physical properties liquid ranges (e.g., acetamide, N-methyl-acetamide and sulfolane are liquid only above ambient temperatures), vapour pressures (Table 3.1), relative permittivities (Table 3.5), viscosities (Table 3.9), and chemical properties, such as electron pair and hydrogen bond donicities (Table 4.3), dissolving ability of the required supporting electrolyte to provide adequate conductivity, and electrochemical potential windows (Table 4.8). A suitable solvent can therefore generally be found among them that fits the electroanalytical problem to be solved. 

Electrochemical fluorination 168,169> is a commercial process for perfluorina-tion of aliphatic compounds. The reaction is performed in liquid hydrogen fluoride -potassium fluoride at a nickel anode. The mechanism is not known free fluorine cannot be detected during electrolysis, so it seems probable that fluorination is a direct electrochemical reaction. Theoretically, hydrogen fluoride-potassium fluoride should be a very oxidation-resistant SSE, and it might well be that the mechanism is analogous to that proposed for anodic acetamidation of aliphatic compounds in acetonitrile-tetrabutylammonium hexafluorophosphate 44 K... 

Controlled potential electrolysis at a mercury pool cathode, carried out at the plateau of the first reduction wave of At-(2-nitrobenzoyl)acetamide, leads in practically quantitative yield to 2-methylquinazolin-4(3/f)-one 1-oxide (mp >260°C), resulting from a ring closure of the A-phenylhydroxylamine intermediate. 2-Methylquinazolin-4(3//)-one 1-oxide is further reduced in Sulfuric acid media to give 2-methylquinazolin-4(3//)-one. A -(2-Nitrobenzoyl)-succinimide and A-(2-nitrobenzoyl)phthalimide undergo similar electrochemical reduction and cyclization to quinazoline derivatives. ... 

The physical technique with the greatest potential for synthetic applications of Ritter-type reactions is electrochemistry. A selection only of examples is discussed here. Synthetic chemists unfamiliar with this technique will find the review by Eberson and Nyberg an informative and entertaining introduction to this area. Electrochemical Ritter reactions may be performed through anodic substitution of a hydrogen by the nitrile, followed by hydrolysis of the nitrilium ion intermediate, as shown in Scheme 42. The majority of reactions investigated have been anodic acetamidations using hydrocarbons, alkyl halides, esters or ketones as the substrate. In some cases, such as reaction of the adamantane derivatives (83), the yields of amide product are excellent (Scheme 43). 

Miscellaneous reactions which involve the cyclization of one component to an aziridine by a polar reaction include the electrochemical oxidative cyclization of / -(p-toluenesulfonyl) aminomalonates to 2,2-bis(carbomethoxy)-JV-(p-toluenesulfonyl)aziridines <88CL1065> and the bromonium ion-mediated cyclization of JV-propargyl acetamides to 2-(2-bromoalkylidene)aziridines... 

Liu P, Du YP, Yang QQ et al (2006) Electrochemical behavior of Fe (II) in acetamide-urea-NaBr-KBr melt and magnetic properties of inductively codeposited Nd-Fe film. Electrochim Acta 52 710-718... 

Although anodic benzylic substitution reactions take place readily, anodic benzylic fluorination does not always occur. The major competitive reaction is acetamidation when MeCN is used as a solvent. For example, electrochemical benzylic fluorination in MeCN proceeded selectively when the benzylic position was substituted by an electron-donating group, as shown in Scheme 4 [8]. In contrast,... 

Electrochemical study of the acid-base properties of a solution in molten 267 acetamide... 

Gil ED, Kubota LT (2000) Electrochemical behavior of rhodium acetamidate immobilized on a carbon paste electrode a hydrazine sensor. J Braz Chem Soc 11 304—310... 

Hu Y, Li H, Huang X, Chen L (2004) Novel room temperature molten salt electrolyte based on liTFSI and acetamide for lithium batteries. Electrochem Commun 6(l) 28-32. doi 10.1016/j.elecom.2003.10.009... 

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