Cyanides s. Nitriles

Auxiliary-controlled Streeker syntheses have so far only been carried out with amines serving as the chiral components. In the first asymmetric Streeker synthesis a solution of sodium cyanide, ( — )-(S)-a-methylbeuzylamine and its hydrochloride in water was mixed with a methanolie solution of acetaldehyde and stirred for five days. Hydrolysis of the resulting amino nitrile and subsequent hydrogenolysis furnished L-alanine with 90% optical purity 38-39-85. 

Hartung, R. 1994. Cyanides and nitriles. In Patty s Industrial Hygiene and Toxicology, 4th ed., vol. II, Part D. John Wiley Sons, pp. 3119-3172. 

Hartung R. 1982. Cyanides and nitriles. In Clayton GD, Clayton FE, eds. Patty s industrial hygiene and toxicology. Vol IIC, 3rd ed. New York, NY John Wiley and Sons, 4845-4900. 

Cyanide and nitriles are reduced to alkanes and ammonia with nitrogenase and reductant. (Cyanide is in equilibrium with HCN in aqueous solution.) Cyanide binds to the S = 3/2 state of the extracted FeMoco in solution, but not to the M state of holo-MoFe protein. Cyanide binds to mutants with changes in the belt region, as is evident from C ENDOR signatures. Kinetics data suggest that cyanide binds to a more oxidized state of the FeMoco than N2 does, and a lag time may indicate a rearrangement. ... 

Aromatic nitriles (or aryl cyanides) can be obtained by methods (1) and (3). but not by method (2). In addition, aromatic nitriles can be prepared by two other methods, (a) from the corresponding diazo compound by Sandmeyer s Reaction (p. 189), (b) by fusing the corresponding sulphonic acid (or its salts)... 

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.). 

Nucleophilic substitution by cyanide ion (Sections 8.1, 8.13) Cyanide ion is a good nucleophile and reacts with alkyl halides to give nitriles. The reaction is of the S m2 type and is limited to primary and secondary alkyl halides. Tertiary alkyl halides undergo elimination aryl and vinyl halides do not react. 

Reaction of the following S tosylate with cyanide ion yields a nitrile product that also has S stereochemistry. Explain. 

Woodward s strychnine synthesis commences with a Fischer indole synthesis using phenylhydrazine (24) and acetoveratrone (25) as starting materials (see Scheme 2). In the presence of polyphosphor-ic acid, intermediates 24 and 25 combine to afford 2-veratrylindole (23) through the reaction processes illustrated in Scheme 2. With its a position suitably masked, 2-veratrylindole (23) reacts smoothly at the ft position with the Schiff base derived from the action of dimethylamine on formaldehyde to give intermediate 22 in 92% yield. TV-Methylation of the dimethylamino substituent in 22 with methyl iodide, followed by exposure of the resultant quaternary ammonium iodide to sodium cyanide in DMF, provides nitrile 26 in an overall yield of 97%. Condensation of 2-veratryl-tryptamine (20), the product of a lithium aluminum hydride reduction of nitrile 26, with ethyl glyoxylate (21) furnishes Schiff base 19 in a yield of 92%. 

To a solution of 2.5 g (8.56 mmol) of methyl 4,6-0-(S/5)-benzylidene-2-deoxy-2,2-diniethyl-a-D-3-hexulopy-ranoside, in 100 mL of CH3OH in a stainless steel pressure bottle are added 7 g (130 mmol) of NI14C1 and 8 g (123 mmol) of potassium cyanide. The mixture is cooled to — 78 "C and, under an ammonia gas stream, it is stirred for 30 min. The bottle is then carefully closed and the mixture is stirred for 1 week. The CH3OH is evaporated, and the residue dissolved in CH2C l2, then filtered. Flash chromatography (CII,CI2/hexanc/EiOAc 80 19 1) affords the pure crystalline amino nitrile yield 2 g (73%) mp 152 154°C [a] ,° +1.21 (CHC13). 

Interestingly, the diastereofacial selectivity can be reversed in the Strecker reaction of aldimines derived from galactosylamine 1 by simply changing the solvent. When the reaction of trimethylsilyl cyanide with the Schiff bases 2 catalyzed by zinc chloride, is carried out in chloroform instead of 2-propanol, there is a preferred formation of the (.S)-amino nitrile diastereomers63. 

Sandmeyer s synthesis of aromatic nitriles is far more elegant than the removal of water from the ammonium salts of carboxylic acids, which latter reaction is also applicable to benzene derivatives. In particular, the former synthesis permits of the preparation of carboxylic acids via the nitriles, and so provides a complete substitute for Kolbe s synthesis (alkyl halide and potassium cyanide), which is inapplicable to aromatic compounds. The simplest example is the conversion of aniline into benzoic add. The converse transformation is Hofmann s degradation (benzamide aniline, see p. 152). 

Sandmeyer s valuable isatin synthesis involves the removal of sulphur from diphenylthiourea (I) (p. 169) with basic lead carbonate. Hydrogen cyanide is combined with the reactive diphenylcarbodiimide (II) so obtained, and the nitrile (III) produced is converted by means of hydrogen sulphide into tbe thioamide (IV). Concentrated sulphuric acid brings about ring closure and the product is the a-anil of isatin (V). Then, by hydrolysis with dilute sulphuric acid, aniline is removed ... 

Synonyms Acritet Acrylon Acrylonitrile monomer AI3-00054 AN BRN 0605310 Carbacryl Caswell No. 010 CCRIS 8 Cyanoethene Cyanoethylene EINECS 203-466-5 ENT 54 EPA pesticide chemical code 000601 Fumigrain Miller s fumigrain NCI-C50215 Nitrile NSC 6362 Propenenitrile 2-Propenenitrile RCRA waste number U009 TL 314 UN 1093 VCN Ventox Vinyl cyanide. 

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