Hydrolysis of a Cyano Group

Bis[2-cyanoethyl] tellurium was hydrolyzed by refluxing in 6 molar hydrochloric acid to bis 2-carboxyethyl] tellurium  

Hydrolysis in a basic medium produced colored polytellurides.  

Bis[2-carboxyethyl] Tellurium In a 50-w/flask equipped with a magnetic stirrer and a reflux condenser are placed 4g (17 mmol) of bis[2-cyanoethyl] tellurium and 10 m/ of 6M hydrochloric acid. The mixture is heated under reflux, the flask is then cooled in ice, and the crystalline precipitate is collected by filtration. Recrystallization from aqueous acetone removes tellurium from the product yield 4g (87%) m.p. 160°. 

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Hydrolysis of a Cyano Group to an Amide in Aqueous Base (Section 18.4E)... 

In hydrolysis of a cyano group in aqueous acid, protonation of the nitrogen atom gives a cation that reacts with water to give an imidic acid (the enol of an amide). Keto-enol tautomerism of the imidic acid gives an amide. The amide is then hydrolyzed, as already described, to a carboxylic acid and an ammonium ion. 

The reaction conditions required for acid-catalyzed hydrolysis of a cyano group are typically more vigorous than those required for hydrolysis of an amide, and in the presence of excess water, a cyano group is hydrolyzed first to an amide and then to a carboxylic acid. It is possible to stop at the amide by using sulfuric acid as a catalyst and one mole of water per mole of nitrile. Selective hydrolysis of a nitrile to an amide, however, is not a good method for the preparation of amides. They are better prepared from acid chlorides, acid anhydrides, or esters. 

Hydrolysis of a cyano group in aqueous base gives a carboxylate anion and ammonia. The reaction is driven to completion by the acid-base reaction between the carboxylic acid and base to form a carboxylate anion. Acidification of the reaction mixture during workup converts the carboxylate anion to the carboxylic acid. 

Hydrolysis of a cyano group in aqueous base involves initial formation of the anion of an imidic acid, which, after proton transfer from water, undergoes keto-enol tautomerism to give an amide. The amide is then hydrolyzed by aqueous base, as we saw earlier, to the carboxylate anion and ammonia. 

Show how to bring about the following conversions using as one step the hydrolysis of a cyano group. 

A solution of sodium cyanide [143-33-9] (ca 25%) in water is heated to 65—70°C in a stainless steel reaction vessel. An aqueous solution of sodium chloroacetate [3926-62-3] is then added slowly with stirring. The temperature must not exceed 90°C. Stirring is maintained at this temperature for one hour. Particular care must be taken to ensure that the hydrogen cyanide, which is formed continuously in small amounts, is trapped and neutrali2ed. The solution of sodium cyanoacetate [1071 -36-9] is concentrated by evaporation under vacuum and then transferred to a glass-lined reaction vessel for hydrolysis of the cyano group and esterification. The alcohol and mineral acid (weight ratio 1 2 to 1 3) are introduced in such a manner that the temperature does not rise above 60—80°C. For each mole of ester, ca 1.2 moles of alcohol are added. 

The triazinedione, triazuril (163) is active as a poultry coccidiostat. Diazonium salt 160, prepared from the appropriate aniline, is coupled with the active methylene group of N-carbethoxycyanoacetamide to give 161. Hydrolysis of the cyano group is accompanied by cyclization, and the resulting acid (162) is decarboxylated to triazuril (163) on heating.50... 

Metabolism of the 2,S -isomers proceeds sequentially hydroxylation at the phenoxy group, hydrolysis of the cyano group, and cleavage of the ester linkage (Coats et al. 1989). Fenvalerate and the IS-isomers yield two ester metabolites in feces from hydroxylation at the 4 - and 2 -phenoxy positions. Other significant metabolites were 3-phenoxybenzoic acid and its hydroxy derivatives from the alcohol moiety, 3-(4-chlorophenyl) isovaleric acid and its hydroxy derivatives from the acid moiety, and thiocyanate and carbon dioxide from the cyano moiety (Ohkawa et al. 1979). A slow elimination rate characterizes fenvalerate and other a-cyano pyrethroids when compared with... 

Treatment of MFA (1) with cyanogen bromide [6] opened ring G to yield the bromo derivative 3 [7]. Attempts to dehydrobrominate 3 in one step via a base-catalyzed elimination with DBU/CH3CN, KOH/MeOH, or terr-BuOK/DMSO were unsuccessful. However, the required methylene entity could be introduced by converting 3 first to a selenide, then oxidation with periodate, followed by thermolysis in benzene to provide compound 4. Hydrolysis of the cyano group with NaOH in ethylene glycol [8] produced 5 (50% yield). Osmium catalyzed oxidation of 5 in the presence of 4-methylmorpholine A-oxide (NMO) gave a diol, which was cleaved to an aldehyde upon treatment with periodate. Treatment of the aldehyde with sodium cyanoborohydride resulted in an intramolecular reductive animation to yield the desired product PHB (6). 

The use of a metal-acid reducing medium is unsatisfactory since extensive hydrolysis of the cyano group occurs. Catalytic hydrogenation over a Raney nickel catalyst (Section 2.17.1, p. 87), in the presence of excess ammonia to suppress secondary amine formation, is illustrated by the preparation of 2-phenyl-ethylamine (cognate preparation in Expt 5.194). The secondary amine may be formed by the following sequence. 

Allyl cyanides can be added across alkynes in the presence of a nickel catalyst prepared from (COD)2Ni and (4-CF3CeH4)3P in situ to give functionalized di- or tri-substituted acrylonitriles in a highly stereoselective manner, presumably via n-allylnickel intermediates. a-Siloxyallyl cyanides also react at the y -position of a cyano group with both internal and terminal alkynes to give silyl enol ethers, which can be converted into the corresponding aldehydes or ketones upon hydrolysis.70... 

C-Mannich bases deriving from hydrogen cyanide make it possible to obtain, upon hydrolysis of the cyano group, a-amino acids 516, which are employed largely as complexants the well-known ethylenediaminetetraacetic acid (EDTA) is the main representative of this group of compounds. 

Aminobenzonitrile is prepared by reduction of 3-nitrobenzonitrile by sodium disulfide in aqueous suspension (63%). This reagent causes some hydrolysis of the cyano group. A selective hydrogenation of the more reactive nitro group in the presence of the cyano group can also be done, e.g., in the preparation of p-aminobenzyl cyanide (7S>%). ... 

Construction of the suitably substituted geranic acid for making the furan ring has been effected too. For example, Poulter et al. have prepared the substituted geranate 865 by reaction of 4-methyl-3-pentenylcopper with the acetylenic ester 866. The ester 865 then underwent cyclization in the presence of acid to the lactone 867, related to scobinolide (161), and the action of acid on the lactol produced from 867 with diisobutylaluminum hydride gave perillene (849). The lactone 867 has also been prepared by a slightly different method the C9 alcohol 868 was made (in poor yield) from isobutenol and prenyl chloride with butyllithium. The extra carbon atom was introduced by the action of sodium cyanide on the epoxide of 868, and hydrolysis of the cyano group followed by dehydration yielded the lactone 867. The dimethylthioacetal of 867 has been used to synthesize perillene (849). This thioacetal was made from the suitably substituted ketene thioacetal 869 and dimethylsulfonium methylide. Thus the ketene thioacetal 870 (readily prepared from acetone, carbon disulfide, and sodium amylate, followed by methylation °) can be prenylated with lithium... 

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