Meyer reaction

Benzylphenylarsinic Acid. CeH5 CH2(C6H5) As 0(0H). (The Meyer Reaction.)... 

The Meyer Reaction in arsenic chemistry bears some analogy to the Arbusov Reaction in phosphorus chemistry. 

To meet the needs of the advanced students, preparations have now been included to illustrate, for example, reduction by lithium aluminium hydride and by the Meerwein-Ponndorf-Verley method, oxidation by selenium dioxide and by periodate, the Michael, Hoesch, Leuckart and Doebner-Miller Reactions, the Knorr pyrrole and the Hantzsch collidine syntheses, various Free Radical reactions, the Pinacol-Pinacolone, Beckmann and Arbusov Rearrangements, and the Bart and the Meyer Reactions, together with many others. 

In the examples, a nitro group is substituted for a hydrogen atom, and water is a by-product. Nitro groups may, however, be substituted for other atoms or groups of atoms. In Victor Meyer reactions which use silver nitrite, the nitro group replaces a hahde atom, eg, I or Br. In a modification of this method, sodium nitrite dissolved in dimethyl formamide or other suitable solvent is used instead of silver nitrite (1). Nitro compounds can also be produced by addition reactions, eg, the reaction of nitric acid or nitrogen dioxide with unsaturated compounds such as olefins or acetylenes. 

Arsonic and Arsinic Acids. The arsonic acids, compounds of the type RAsO(OH)2, are among the most important organic arsenicals. The ahphatic arsonic acids are generally prepared by the Meyer reaction ie, heating an alkyl haUde with As O in alkaline solution ... 

Where X is Br or Q, the free acids may be obtained by acidification of the alkaline solution, but where X is I, the acids must be isolated as salts to avoid reduction of the arsonic acids by HI. Rather than using alkyl haUdes, alkyl or dialkyl sulfates or alkyl arenesulfonates can be used. Primary alkyl haUdes react rapidly and smoothly, secondary haUdes react only slowly, whereas tertiary haUdes do not give arsonic acids. AHyl haUdes undergo the Meyer reaction, but vinyl hahdes do not. Substituted alkyl haUdes can be used eg, ethylene chlorohydrin gives 2-hydroxyethylarsonic acid [65423-87-2], C2H2ASO4. Arsinic acids, R2AsO(OH), are also readily prepared by substituting an alkaU metal arsonite, RAs(OM)2, for sodium arsenite ... 

Arsonic acids RAsO(OH)2 are amongst the most important organoarsonium compounds. Alkyl arsonic acids are generally prepared by the Meyer reaction in which an alkaline solution of AS2O3 is heated with an alkyl halide ... 

Historical. NMe was First prepd by Victor Meyer who treated Me iodide with Ag nitrite and obtained a 90% yield (Ref 2). This proc came to be known as the Victor Meyer reaction (Ref 50). It has also been prepd by the action of Me sulfate on K nitrite (Ref 3). In the Victor Meyer reaction the ratio of NMe to Me nitrite obtained was found to be dependent upon solv, temp, and the reagents used (Ref 5)... 

In exptl work, indirect methods of introducing nitro groups find wide application as, for example, the replacement of a halogen (iodine or bromine in an alkyl iodide or bromide) by the nitro group, by means of silver nitrite (the Victor Meyer reaction)... 

Naphthalenedicarboxylic acid has been prepared by the present method2 and by hydrolysis of 3-cyano-2-naphthoic acid, which is obtainable from 3-amino-2-naphthoic acid by the Sand-meyer reaction.3... 

The reaction of alkyl halides with metal nitrites is one of the most important methods for the preparation of nitroalkanes. As a metal nitrite, silver nitrite (Victor-Meyer reaction), potassium nitrite, or sodium nitrite (Kornblum reaction) have been frequently used. The products are usually a mixture of nitroalkanes and alkyl nitrites, which are readily separated by distillation (Eq. 2.47). The synthesis of nitro compounds by this process is well documented in the reviews, and some typical cases are listed in Table 2.3.92a Primary and secondary alkyl iodides and bromides as well as sulfonate esters give the corresponding nitro compounds in 50-70% yields on treatment with NaN02 in DMF or DMSO. Some of them are described precisely in vol 4 of Organic Synthesis. For example, 1,4-dinitrobutane is prepared in 41 -46% yield by the reaction of 1,4-diiodobutane with silver nitrite in diethyl ether.92b 1-Nitrooctane is prepared by the reaction with silver nitrite in 75-80% yield. The reaction of silver nitrite with secondary halides gives yields of nitroalkanes of about 15%, whereas with tertiary halides the yields are 0-5%.92c Ethyl a-nitrobutyrate is prepared by the reaction of ethyl a-bromobutyrate in 68-75% yield with sodium nitrite in DMF.92d Sodium nitrite is considerably more soluble in DMSO than in DMF as a consequence, with DMSO, much more concentrated solutions can be employed and this makes shorter reaction times possible.926... 

Primary alkyl iodides and bromides are excellent substrates for the Victor Meyer reaction, providing a route to both substituted and unsubstituted nitroalkanes (Table i. i).63,65,70,7i formation of the corresponding nitrite ester is a side-reaction and so the nitroalkane is usually isolated by distillation when possible. The reaction of primary alkyl chlorides with silver nitrite is too slow to be synthetically useful. Secondary alkyl halides and substrates with branching on... 

The synthesis of aliphatic nitro compounds from the reaction of alkyl halides with alkali metal nitrites was discovered by Kornblum and co-workers and is known as the modified Victor Meyer reaction or the Kornblum modification. The choice of solvent in these reactions is crucial when sodium nitrite is used as the nitrite soiuce. Both alkyl halide and nitrite anion must be in solution to react, and the higher the concentration of nitrite anion, the faster the reaction. For this reason, both DMF and DMSO are widely used as solvents, with both able to dissolve appreciable amounts of sodium nitrite. Although sodium nitrite is more soluble in DMSO than DMF the former can react with some halide substrates.Urea is occasionally added to DMF solutions of sodium nitrite to increase the solubility of this salt and hence increase reaction rates. Other alkali metal nitrites can be used in these reactions, like lithium nitrite,which is more soluble in DMF than sodium nitrite but is also less widely available. 

Methyl-l,4,7-triazacyclononane, cobalt(III) hexaamines, 35 144 Meyer reaction... 

The Meyer reaction is intrinsically reversible. As the pH rises and arsenite becomes progressively dehydronated, it becomes an increasingly good nucleophile, whereas it becomes an increasingly good leaving group as the pH falls and the C—As bond can break (see 75, p. 987). 

In our synthesis (57) of the arsonomethyl analogue of AMP, we developed a method (Fig. 12) for converting an alcohol, R—CH2—OH, into the arsonomethyl analogue, R—CH2—CH2—As03H2, of its phosphate, R—CH2— —P03H2. In this pathway the Meyer reaction is used on a 2-halocarboxylic acid, so that the reactant will be soluble in aqueous... 

When we required 3-arsonopyruvate, it was similarly necessary to make the labile -CO—CH2—As03H2 structure only at the last stage, and again we used periodate for this (68), as shown in Fig. 15. The pathway makes use of the recently emphasized (76) fact that when the Meyer reaction (Section VII,A,1) is performed with a 2-haloalcohol, the halide is not directly displaced by arsenite, but the alkali first causes formation of an epoxide, which is then opened by arsenite at its less hindered carbon. As with the arsonoacetaldehyde, the compound was not isolated from solution. 

MEYER REACTION. Preparation of alkylstaimonic acids by reacting alkali stanniic with an alkyl iodide. When applied to alkali ursenites or plumbites. the reaclion yields alkylarsonic and alkylpiumbonic acids, respectively. 

Chloromethylpyridine is converted to 2-picolylarsonic acid in quantitative yield by Meyer reaction with arsenic(m) oxide in an aqueous sodium hydroxide solution <2002PS2773>. 

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