Cyanides propionitrile

Ethylbenzene Phenylethane 72 CsHio n-Propionitrile Ethyl cyanide 178 C4H5N... 

The formation of ethyl cyano(pentafluorophenyl)acetate illustrates the intermolecular nucleophilic displacement of fluoride ion from an aromatic ring by a stabilized carbanion. The reaction proceeds readily as a result of the activation imparted by the electron-withdrawing fluorine atoms. The selective hydrolysis of a cyano ester to a nitrile has been described. (Pentafluorophenyl)acetonitrile has also been prepared by cyanide displacement on (pentafluorophenyl)methyl halides. However, this direct displacement is always aecompanied by an undesirable side reaetion to yield 15-20% of 2,3-bis(pentafluoro-phenyl)propionitrile. 

Nitriles are organic derivatives of hydrocyanic acid in which the substituting group is attached to carbon. Their formula is R.C N. Because most nitriles can be derived from corresponding acid amides, R.CO.NH2, by removal of w, they are called nitriles. For instance, the compd CH3.CN is called acetonitrile because it is derived from acetamide. It can also be called methyl cyanide. The compd C2HS.CN is called either propionitrile or ethyl cyanide, etc The first nitrile to be prepared was propionitrile which J. Pelouze obtained in 1834 by distg Ba ethyl sulfate with K cyanide... 

Vesey et al. 1976) and a series of commercially important, simple, aliphatic nitriles (e.g., acetonitrile, propionitrile, acrylonitrile, n-butyronitrile, maleonitrile, succinonitrile) (Willhite and Smith 1981) release cyanide upon metabolism. These drugs and industrial chemicals have been associated with human exposure to cyanide and have caused serious poisoning and, in some cases, death. 

Cycloadditions to a cyano group are comparatively rare. The high-temperature reactions of 1,3-dienes, e.g. butadiene, isoprene and 2-chloro-l,3-butadiene, with dicyanogen, propionitrile or benzonitrile result in formation of pyridines (equation 80)70. Sulfonyl cyanides 147, obtained by the action of cyanogen chloride on sodium salts of sulfinic acids, add to dienes to give dihydropyridines 148, which are transformed into pyridines 149 by oxidation (equation 81)71. 

Another way to synthesize ibuprofen consists of the chloromethylation of Ao-butylben-zene, giving 4-Ao-butylbenzylchloride (3.2.24). This product is reacted with sodium cyanide, making 4-Ao-butylbenzyl cyanide (3.2.25), which is alkylated in the presence of sodium amide by methyl iodide into 2-(4-iAo-butylbenzyl)propionitrile (3.2.26). Hydrolysis of the resulting product in the presence of a base produces ibuprofen (3.2.23). 

With DIOP-Pd(0) or -Ni(0) complexes as catalysts, moderate optical yields of up to 35% have been observed (126). Norbomene is convertible to the exo nitrile with up to 40% ee when a BINAP-Pd(0) complex is used (Scheme 57) (127). Ni(0) complexes of sugar-derived 1,2-diol phosphinites catalyze highly selective asymmetric addition of hydrogen cyanide to vinylarenes (128). This method gives the 2-naphthalene-2-propionitrile precursors of nonsteroid anti-inflammatory agents in up to 85% ee and in high yield. 

The title olefins form complexes with Ni(0) with equilibrium constants for formation decreasing in the order ethylene > styrene > propylene 1-hexene > disubstituted alkenes (28). With ethylene and styrene the (olefin)NiL2 complexes have been isolated with L = P(0-o-tolyl)3. Addition of HCN to solutions of the pure olefin complexes results in rapid and complete conversion to alkylnickel cyanide intermediates which are spectroscopically detectable subsequent C—C coupling gives the observed nitrile products propionitrile from ethylene and (predominantly) 2-phenylpropion-itrile from styrene (47). The same alkyl intermediates are formed when ethylene and styrene are added to HNiL3CN [L = p(0-o-tolyl)3]. 

Reaction XLVIII. (c) Action of Dimethyl Sulphate on Potassium Cyanide. (B., 40, 3215.)—This method gives excellent yields of acetonitrile diethyl sulphate yields propionitrile by a similar method. Prepaeation 80.—Acetonitrile (Methyl Cyanide). 

Nitriles may be prepared by several methods (1). The first nitrile to be prepared was propionitrile, which was obtained in 1834 by distilling barium ethyl sulfate with potassium cyanide. This is a general preparation of nitriles from sulfonate salts and is referred to as the Pelouze reaction (2). Although not commonly practiced today, dehydration of amides has been widely used to produce nitriles and was the first commercial synthesis of a nitrile. The reaction of alkyl halides with sodium cyanide to produce nitriles (eq. 1) also is a general reaction with wide applicability ... 

The propensity of nitriles to release cyanide subsequent to metabolism is the basis of their acute toxicity. Nitriles that form tertiary radicals at their alpha carbon atoms (eg, isobutyronitrile, 2-methylbutyronitrile) are substantially more acutely lethal than nitriles that form secondary radicals at their alpha carbons (eg, butyronitrile, propionitrile). Cyanohydrins are acutely toxic because they are unstable and release cyanide quickly. Alpha-aminonitriles are also acutely toxic, presumably by analogy with cyanohydrins. 

Nitrile-stabilized anions, generated for example by lithiation of benzyl cyanide and propionitrile, have been added diastereoselectively to aromatic aldimines.50 Acid workup gives /5-cyano amines. Alternatively, addition of RX gives /3-R-substituted-/3-cyanoamines. The factors determining des in both reaction versions have been investigated. 

Nitriles are cyanogenic substances — substances that produce cyanide when metabolized. It is likely that nitriles are teratogens because of maternal production of cyanide in pregnant females. A study of the teratogenic effects on rats of saturated nitriles, including acetonitrile, propionitrile, and n-butyronitrile, and of unsaturated nitriles, including acrylonitrile, methacrylonitrile, allylnitrile, m-2-pcntenenitrile, and 2-chloroacrylonitrile, has shown a pattern of abnormal embryos similar to those observed from administration of inorganic cyanide.6... 

Phenoxyphenyl)Propionitrile A well-stirred suspension of 316 grams of 98% sodium cyanide in 5,000 ml of anhydrous dimethyl sulfoxide (previously dried over molecular sieve) was warmed to 55° to 60°C and maintained at this temperature while 1,702 grams of a-methyl-3-phenoxybenzyl bromide was slowly added. After the bromide addition was completed, the temperature was raised to 75°C and the mixture stirred at this temperature for 1.5 hours. The mixture was then allowed to cool to room temperature and was stirred overnight at room temperature and then poured into ice water. The resulting aqueous suspension was extracted twice with ethyl acetate, and then with ether. The organic extract was washed twice with a sodium chloride solution, once with water, and dried over anhydrous sodium sulfate. Evaporation of the... 

Tretyakov and Filimonov (219) describe a coordinative interaction between benzonitrile and aprotic sites on magnesium oxide, and Zecchina et al. (256) came to the same conclusion for the adsorption of propionitrile, benzonitrile, and acrylonitrile on a chromia-silica catalyst. Chapman and Hair (257) observed an additional chemical transformation of benzonitrile on alumina-containing surfaces, which they describe as an oxidation. Knozinger and Krietenbrink (255) have shown that acetonitrile is hydrolyzed on alumina by basic OH- ions, even at temperatures below 100°C. This reaction may be described as shown in Scheme 2. The surface acetamide (V) is subsequently transformed into a surface acetate at higher temperatures. Additional reactions on alumina are a dissociative adsorption and polymerizations (255) analogous to those observed for hydrogen cyanide by Low and Ramamurthy (258), and a dissociative adsorption. Thus, acetonitrile must certainly be refused as a probe molecule and specific poison. 

SAFETY PROFILE Nitriles are organic cyanides acrydonitrile, propionitrile, and some others resemble cyanides in toxicity. Other nitriles, such as cyanamides and cyanates, have no cyanide effect. Can react violendy with (LiAlH4 -I- H2O). The nitriles may be used as insecticides. Many are flammable. When heated to decomposition they emit highly toxic fumes of CN . See also specific compounds and CYANIDE. 

At temperatures below 240 °C, there is essentially no gas evolution, with the exception of some HjO after long heating time. In the range 250-300 °C, small amounts of low hydrocarbons (AN, MAN, propionitrile) evolve. These compounds are supposed to proceed from depolymerization of uncyclized parts of the polymer. Hydrogen cyanide starts to evolve after 70 min at 250 °C and after 30 min at 300 °C. The early evolution of HCN has frequently been ascribed to dehydrocyanation (analog to dehydrochlorination from polyvinylchloride), either within a molecule, leading to unsaturation ... 

Toxicokinetic data are available only for propionit-rile. When administered as a " C radioisotope, 92.5% of the compound was recovered. The majority was eliminated in air or urine within 24 h. About 27% was recovered as volatile organic material within 0.5 h of gavage exposure. By 3 h, either carbon dioxide or cyanide exhalation was estimated at 38 9% of the total. At 24 h, the total " C recovery in the urine was 0.76-5.83%. A small amount (<2%) was found in liver and kidneys at 72 h after dosing. It was concluded that propionitrile is rapidly absorbed from the gastrointestinal tract and eliminated through expired air as the parent compound, CO2, or cyanide. 

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