Oxidation of nitriles

It is now well known that the conversion of nitriles into amides can be carried out under a variety of conditions in presence of metal catalyst, 

Using the above method following nitriles have been converted into corresponding amides in 85-95% yield benzonitrile, methyl cyanide and chloromethyl cyanide. 

The quinazolin-4-(3H)-ones are interesting systems to build pharmaceutical compounds. 

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Oxidative hydrolysis of nitriles.2 Potassium r-butoxidc catalyzes the oxidation of nitriles to carboxylic acids with loss of the cyano carbon (equation I). The presence of l8-crown-6 improves yields, which vary from 21 to 93%, being highest with long-chain aliphatic nitriles. 

Epoxidation. This reagent is more reactive than the similar reagents of Payne derived from aceto- and benzonitrile (1, 469-470). Its reactivity is comparable to that of m-chloroperbenzoic acid. It epoxidizes a,(3-cnoncs it does not effect Baeyer-Villiger oxidation or oxidation of nitrile groups. 

RuCl2(PPh3)3 is also a catalyst for the oxidation of nitriles, amides and lactams under moderate conditions. In this respect, its activity resembles that of cytochrome P-450. 

Oxidation of nitrile oxides. A simple access to 0=N-C0R from nitrile oxides is the addition of NMO in a dichloromethane solution at room temperature. The reactive acyl nitroso compounds are trapped (usually with dienes). 

Finally, a few articles have appeared on chemiluminescence of polymers. This technique has been used to detect hydroxy radicals in wood oxidation,y-irradiation effects on polyethylene, oxidation of nitrile-butadiene rubber, rubber under stress,antioxidant efficiencies in polyethylene, reactions of peroxy radicals, stereoregularity in poly(propylene), colour development in epoxy resins and structural changes in thermally aged poly(phenylene sulfide). ... 

Nitrile Oxides. Yet another common reactant type is the family of nitrile oxides. Like nitrones, they are not made by direct oxidation of nitriles but by an indirect method shown in Scheme 5.25, starting with the oxime of an aldehyde. The aldehydic hydrogen is replaced by chlorine, and then HCl is eliminated by reaction... 

Not surprisingly, the hydrolysis of nitriles is the most atom economical reaction. The isohypsic transformations are the acid chloride-Schotten-Baumann sequence, carbodiimide and carbonyl-diimidazole methods, and the hydrolysis of nitriles. The oxidation of nitriles with hydrogen peroxide is hyperhypsic for the reasons mentioned in Section 9.1.1 for the nitrile to carboxylic acid transformation. The umpolung method, which electronically reverses the roles of the reacting partners, is hypohypsic since a net oxidation has occurred at the reactive carbon atom. This is a novel... 

The ruthenium-catalyzed oxidation of nitriles takes place at the a-position to nitriles. For example, the RuCl3-nH20-catalyzed oxidation of benzylcyanide with f-BuOOH gives benzoylcyanide in 94% yield [137]. 

The most general methods for the syntheses of 1,2-difunctional molecules are based on the oxidation of carbon-carbon multiple bonds (p. 117) and the opening of oxiranes by hetero atoms (p. 123fl.). There exist, however, also a few useful reactions in which an a - and a d -synthon or two r -synthons are combined. The classical polar reaction is the addition of cyanide anion to carbonyl groups, which leads to a-hydroxynitriles (cyanohydrins). It is used, for example, in Strecker s synthesis of amino acids and in the homologization of monosaccharides. The ff-hydroxy group of a nitrile can be easily substituted by various nucleophiles, the nitrile can be solvolyzed or reduced. Therefore a large variety of terminal difunctional molecules with one additional carbon atom can be made. Equally versatile are a-methylsulfinyl ketones (H.G. Hauthal, 1971 T. Durst, 1979 O. DeLucchi, 1991), which are available from acid chlorides or esters and the dimsyl anion. Carbanions of these compounds can also be used for the synthesis of 1,4-dicarbonyl compounds (p. 65f.). 

Alkylthiazoles can be oxidized to nitriles in the presence of ammonia and a catalyst. For example, 4-cyanothiazole was prepared from 4-methylthiazole by a one-step vapor-phase process (94) involving reaction with a mixture of air, oxygen, and ammonia at 380 to 460°C. The catalyst was M0O3 and V Oj or M0O3, VjOj, and CoO on an alumina support. 

Adiponitrile undergoes the typical nitrile reactions, eg, hydrolysis to adipamide and adipic acid and alcoholysis to substituted amides and esters. The most important industrial reaction is the catalytic hydrogenation to hexamethylenediarnine. A variety of catalysts are used for this reduction including cobalt—nickel (46), cobalt manganese (47), cobalt boride (48), copper cobalt (49), and iron oxide (50), and Raney nickel (51). An extensive review on the hydrogenation of nitriles has been recendy pubUshed (10). 

Preparation. The industrial production of malonic acid is much less important than that of the malonates. Malonic acid is usually produced by acid saponification of malonates (9). Further methods which have been recendy investigated are the ozonolysis of cyclopentadiene [542-92-7] (10), the air oxidation of 1,3-propanediol [504-63-2] (11), or the use of microorganisms for converting nitriles into acids (12). 

Physical properties for naphthalene mono-, di-, tri-, and tetracarboxyhc acids are summari2ed in Table 9. Most of the naphthalene di- or polycarboxyLic acids have been made by simple routes such as the oxidation of the appropriate dior polymethylnaphthalenes, or by complex routes, eg, the Sandmeyer reaction of the selected antinonaphthalenesulfonic acid, to give a cyanonaphthalenesulfonic acid followed by fusion of the latter with an alkah cyanide, with simultaneous or subsequent hydrolysis of the nitrile groups. 

Other carbon electrophiles which are frequently employed include aldehydes, ketones, esters, nitriles and amides of the type RCONMei. An indirect method of acylation involves the initial reaction of a lithio compound with an aldehyde followed by oxidation of the resulting secondary alcohol to the corresponding acyl derivative. 

In theory, three isoxazolines are capable of existence 2-isoxazoline (2), 3-isoxazoline and 4-isoxazoline. The position of the double bond may also be designated by the use of the prefix A with an appropriate numerical superscript. Of these only the 2-isoxazolines have been investigated in any detail. The preparation of the first isoxazoline, 3,5-diphenyl-2-isoxazoline, from the reaction of )3-chloro-)3-phenylpropiophenone with hydroxylamine was reported in 1895 (1895CB957). Two major syntheses of 2-isoxazolines are the cycloaddition of nitrile A-oxides to alkenes and the reaction of a,/3-unsaturated ketones with hydroxylamine. Since 2-isoxazolines are readily oxidized to isoxazoles and possess some of the unique properties of isoxazoles, they also serve as key intermediates for the synthesis of other heterocycles and natural products. 

The electronic structure of nitrile A-oxides may be represented as a resonance hybrid of the canonical structures (335a-e). The structure (335a) is commonly used to represent this reactive species. 

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