Nitrile complete hydrolysis

Hydrolysis of />-Tolunitrile. As in the case of benzonitrile, alkaline h> drolysis is preferable to hydrolysis by 70% sulphuric acid. Boil a mixture of 5 g. of p-tolunitrile, 75 ml. of 10% aqueous sodium hydroxide solution and 15 ml. of ethanol under a reflux water-condenser. The ethanol is added partly to increase the speed of the hydrolysis, but in particular to prevent the nitrile (which volatilises in the steam) from actually crystallising in the condenser. The solution becomes clear after about i hour s heating, but the boiling should be continued for a total period of 1-5 hours to ensure complete hydrolysis. Then precipitate and isolate the p-toluic acid, CH3CgH4COOH, in precisely the same way as the benzoic acid in the above hydrolysis of benzonitrile. Yield 5 5 g. (almost theoretical). The p-toluic acid has m.p. 178°, and may be recrystallised from a mixture of equal volumes of water and rectified spirit. 

Cyanopyridines are usually manufactured from the corresponding picoline by catalytic, vapor-phase ammoxidation (eq. 7) in a fixed- or fluid-bed reactor (28). 3-Cyanopyridine (25) is the most important nitrile, as it undergoes partial or complete hydrolysis under basic conditions to give niacinamide... 

Generally, enzymatic hydrolysis of nitriles to the corresponding acids can either proceed stepwise, which is the case for catalysis by the nitrile hydratase/amidase enzyme system, or in one step in the case of nitrilases. Both systems have been investigated for surface hydrolysis of PAN [10], Complete hydrolysis with either system was monitored by quantification of ammonia and/or polyacrylic acid formed as a consequence of hydrolysis of nitrile groups [70-72], As a result, considerable increases in colour levels (e.g. 156% for commercial nitrilase) were found upon dyeing [72],... 

DSM developed a slightly different approach towards enantiopure amino acids. Instead of performing the Strecker synthesis with a complete hydrolysis of the nitrile to the acid it is stopped at the amide stage. Then a stereoselective amino acid amidase from Pseudomonas putida is employed for the enantioselective second hydrolysis step [83], yielding enantiopure amino acids [34, 77, 78]. Although the reaction is a kinetic resolution and thus the yields are never higher than 50% this approach is overall more efficient. No acylation step is necessary and the atom efficiency is thus much higher. A drawback is that the racemisation has to be performed via the Schiff s base of the D-amide (Scheme 6.23). 

Hydrolysis of a-phenyl-j8-methylbutyronitrile (p. 252) by the above procedure gives the amide, m.p. 111-112°. In order to complete hydrolysis of the acid, a mixture of 10 g. (0.063 mole) of the nitrile, 20 g. (0.35 mole) of potassium hydroxide, and 50 g. of amyl alcohol is refluxed for 6 hours. Work-up of the reaction mixture as described above gives a-phenyl- -methylbutyric acid, m.p. 61-62°. 

The first total synthesis of amiclenomycin, an inhibitor of biotin biosynthesis, was completed by A. Marquet and co-workers. In order to prove its structure unambiguously, both the cis and trans isomers were prepared. The L-amino acid functionality was installed by a Strecker reaction using TMSCN in the presence of catalytic amounts of Znla. The resulting O-TMS protected cyanohydrin was exposed to saturated methanolic ammonia solution, which gave rise to the corresponding a-amino nitrile. Enzymatic hydrolysis with immobilized pronase afforded the desired L-amino acid. 

The carbon necessary to complete the annotinine skeleton was introduced by treatment of 118 with HON in dimethyl formamide, yielding a mixture of the epimeric nitriles 119. Hydrolysis of the nitriles in methanolic sulfuric acid gave the racemic ester 120 identical... 

Nitriles are related to carboxylic acids because complete hydrolysis of a nitrile produces a carboxylic acid or a carboxylate anion (Sections 16.9 and 17.3) ... 

Hydration and Hydrolysis. In concentrated 85% sulfiiric acid, partial hydrolysis of the nitrile group produces acrylamide sulfate, which upon neutralization yields acrylamide this is the basis for acrylamide s commercial production. In dilute acid or alkali, complete hydrolysis occurs to yield acrylic acid. 

B). Many nitriles when treated with hydrogen peroxide in warm alkaline solution undergo hydrolysis to amides which can thus be readily obtained in high yield. Insoluble liquid nitriles can be treated directly in the aqueous suspension, but for insoluble solid nitriles the addition of a suitable organic solvent to give a complete solution may be desirable, although the completion of the hydrolysis may not then be so readily detected. 

Place together in a 50 ml. conical flask about 1 g. of the substance and 10 ml. of 10% NaOH solution (or use apparatus in Fig. 38, p. 63)-Add a few pieces of unglazed porcelain, fit a reflux water- condenser, and boil gently for about 20 minutes. Nitriles require longer heating than amides, usually about 30 minutes. The completion of the hydrolysis of an insoluble nitrile ( .g., benzonitrile) is indicated by the disappearance of oily drops in the liquid. Cool the flask, add an excess of dil. H2SO4 and cool thoroughly. 

In the Strecker synthesis an aldehyde is converted to an a ammo acid with one more carbon atom by a two stage procedure m which an a ammo nitrile is an mterme diate The a ammo nitrile is formed by reaction of the aldehyde with ammonia or an ammonium salt and a source of cyanide ion Hydrolysis of the nitrile group to a car boxylic acid function completes the synthesis... 

Cyanides are dangerously toxic materials that can cause instantaneous death. They occur in a number of industrial situations but are commonly associated with plating operations, and sludges and baths from such sources. Cyanide is extremely soluble and many cyanide compounds, when mixed with acid, release deadly hydrogen cyanide gas. Cyanide is sometimes formed during the combustion of various nitrile, cyanohydrin, and methacrylate compounds. Cyanides (CN ) are commonly treated by chlorine oxidation to the less toxic cyanate (CNO ) form, then acid hydrolyzed to COj and N. Obviously, care should be taken that the cyanide oxidation is complete prior to acid hydrolysis of the cyanate. 

We aheady discussed both the acidic and basic hydrolysis of fflnides (see Section 20.17). All that remains to complete the mechanistic picture of nitrile hydrolysis is to examine the conversion of the nitrile to the conesponding amide. 

Although the biosynthetic cascade hypothesis predicts the co-occurrence of endiandric acids D (4) and A (1) in nature, the former compound was not isolated until after its total synthesis was completed in the laboratory (see Scheme 6). Our journey to endiandric acid D (4) commences with the desilylation of key intermediate 22 to give alcohol 31 in 95% yield. The endo side chain is then converted to a methyl ester by hydrolysis of the nitrile to the corresponding acid with basic hydrogen peroxide, followed by esterification with diazomethane to afford intermediate 32 in 92% overall yield. The exo side chain is then constructed by sequential bromination, cyanide displacement, ester hydrolysis (33), reduction, and olefination (4) in a straight-... 

The hydrolysis of an organic nitrile, a compound containing a —C=N group, in basic solution, is proposed to proceed by the following mechanism. Write a complete balanced equation for the overall reaction, list any intermediates, and identify the catalyst in this reaction. 

Hydrolysis of benzonitrile to benzoic acid. Boil 5 1 g. (5 ml.) of benzo-nitrile and 80 ml. of 10 per cent, sodium hydroxide solution in a 250 ml. round-bottomed flask fitted with a reflux water condenser until the condensed liquid contains no oily drops (about 45 minutes). Remove the condenser, and boil the solution in an open flask for a few minutes to remove free ammonia. Cool the liquid, and add concentrated hydrochloric acid, cautiously with shaking, ontil precipitation of benzoic acid is complete. Cool, filter the benzoic acid with suction, and wash with cold water dry upon filter paper in the air. The benzoic acid (5-8 g.) thus obtained should be pure (m.p. 121°). Recrystal-lise a small quantity from hot water and redetermine the m.p. 

Empirically, we found that to ensure complete reaction one needs a 0.5 molar equiv of the zinc salt (ZnXj) however, in many cases, lower loadings of zinc may be used. The chief competing reaction is hydrolysis of the nitrile to the primary amide therefore, in cases where the tetrazole-forming reaction is sufficiently fast, namely, with... 

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