Cyanides described

A more recent, extended study of purine synthesis via polymerisation of ammonium cyanide, described at the beginning of this section, showed that the yield of adenine from the non-hydrolyzed solution was only slightly temperature dependent. Shorter hydrolysis times for the insoluble polymerisation products led to higher adenine yields. When the solution is hydrolyzed at pH 8, the adenine yield is comparable to the value of 0.1% found for acidic hydrolysis (a model for the primeval ocean ). Increasing the hydrolysis time has no effect on the adenine yield because of its greater stability at pH 8. Hydrolysis of the black NH4CN polymer under acidic or neutral conditions results in an adenine yield of about 0.05% (Borquez et al., 2005). 

The field of transition metal cyanide chemistry has a remarkable history that spans almost three centuries, dating back to the early eighteenth century. The wide availability of transition metal cyanide complexes together with their diverse bonding and structural chemistry has led to their widespread applications in the field of materials chemistry. Several detailed reviews on metal cyanides describing their structures, reactivity, and physical properties have been published over the years.A fully comprehensive review highlighting the most important advances in this area was written by Dunbar and Heintz in 1997. ... 

These water-insoluble acid-resistant complex iron cyanides are widely used as pigments and hence their detection, if need be in the presence of other materials, is of technical significance. The rapid test given here is based on the finding that Prussian Blue (I) and TurnbulFs Blue (II) yield dicyanogen when subjected to thermal decomposition. This volatile product responds to the reaction with oxine and alkali cyanide described on page 356. The partial reactions underlying the thermal production of (CN)2 are ... 

Furthermore, at all concentrations below 10 M the reactions are first order with respect to DHF that is, the values of approximately 4 X 10 M sec represent true second order constants. The tendency to smaller values in manometric systems is probably indicative of other limiting reactions, for example, reactions between peroxide and enzyme, rather than of deviations from second order behavior in the reaction with DHF itself. The action of cyanide described below lends support to this view. 

Halogens. Test the second portion of the filtrate for halogens in the usual way, as described under the Lassaigne halogen test (p. 324). Note that cyanides if present must first be eliminated as usual. 

Cuprous cyanide solution. The most satisfactory method is to dissolve the cuprous cyanide (1 mol) in a solution of technical sodium cyanide (2 5-2-6 mols in 600 ml. of water). If it is desired to avoid the preparation of solid cuprous cyanide, the following procedure may be adopted. Cuprous chloride, prepared from 125 g. of copper sulphate crystals as described under 1 above, is suspended in 200 ml. of water contained in a 1-litre round-bottomed flask, which is fitted with a mechanical stirrer. A solution of 65 g. of technical sodium cyanide (96-98 per cent.) in 100 ml. of water is added and the mixture is stirred. The cuprous chloride passes into solution with considerable evolution of heat. As the cuprous cyanide is usually emplo3 ed in some modification of the diazo reaction, it is usual to cool the resulting solution in ice. 

Strictly speaking the alkyl halides are esters of the halogen acids, but since they enter into many reactions (t.g., formation of Grignard reagents, reaction with potassium cyanide to yield nitriles, etc.) which cannot be brought about by the other eaters, the alkyl halides are usually distinguished from the esters of the other inorganic acids. The preparation of a number of these is described below. 

Suberic acid. Prepare hexamethylene dibromide from hexamethy-lene glycol (Section 111,15) according to the procedure described in Section 111,35). Convert the 1 6-dibromohexane, b.p. H4r-115°/12 mm., into hexamethylene dicyanide, b.p. 178-180°/15 mm., by refluxing it with a 20-25 per eent. excess of aqueous - alcoholic sodium cyanide solution (compare Section 111,114), distilling off the hquid under diminished... 

Commercial zinc cyanide is quite satisfactory. It may be prepared as described in Section 11,50,iS. If the zinc cyanide is too highly purified, it does not react well. 

Halogens. Proceed as described under the Lassaigne test. If nitro gen is present, the cyanide must first be eliminated. 

Chrysean (10), prepared by bubbling hydrogen sulfide through a sodium cyanide solution, was among the first described thiazoles (53-57). Other 5-aminothiazoles are also most easily prepared bv hetero-cyclization (see Chapter 11. Section II.5.A). 

In a related process, 1,4-dichlorobutene was produced by direct vapor-phase chlorination of butadiene at 160—250°C. The 1,4-dichlorobutenes reacted with aqueous sodium cyanide in the presence of copper catalysts to produce the isomeric 1,4-dicyanobutenes yields were as high as 95% (58). The by-product NaCl could be recovered for reconversion to Na and CI2 via electrolysis. Adiponitrile was produced by the hydrogenation of the dicyanobutenes over a palladium catalyst in either the vapor phase or the Hquid phase (59,60). The yield in either case was 95% or better. This process is no longer practiced by DuPont in favor of the more economically attractive process described below. 

Formation of cyanide by degradation of hydantoia derivatives used as antiseptics for water treatment has been described (84), and this fact might have toxicological relevance. 

Cmde HCl recovered from production of chlorofluorocarbons by hydrofluorination of chlorocarbons contains unique impurities which can be removed by processes described in References 53—62. CICN—CI2 mixtures generated by reaction of hydrogen cyanide and CI2 during the synthesis of (CICN) can be removed from the by-product HCl, by fractional distillation and recycling (see Cyanides) (59). 

Synthetic chemical approaches to the preparation of carbon-14 labeled materials iavolve a number of basic building blocks prepared from barium [ CJ-carbonate (2). These are carbon [ C]-dioxide [ CJ-acetjlene [U— C]-ben2ene, where U = uniformly labeled [1- and 2- C]-sodium acetate, [ C]-methyl iodide, [ C]-methanol, sodium [ C]-cyanide, and [ CJ-urea. Many compHcated radiotracers are synthesized from these materials. Some examples are [l- C]-8,ll,14-eicosatrienoic acid [3435-80-1] inoxn. [ CJ-carbon dioxide, [ting-U— C]-phenyhsothiocyanate [77590-93-3] ftom [ " CJ-acetjlene, [7- " C]-norepinephrine [18155-53-8] from [l- " C]-acetic acid, [4- " C]-cholesterol [1976-77-8] from [ " CJ-methyl iodide, [l- " C]-glucose [4005-41-8] from sodium [ " C]-cyanide, and [2- " C]-uracil [626-07-3] [27017-27-2] from [ " C]-urea. All syntheses of the basic radioactive building blocks have been described (4). 

New teipolymers of vinyl acetate with ethylene and carbon monoxide have been prepared and their uses as additives to improve the curing and flexibihty of coating resins, eg, nitrocellulose, asphalt, phenoHcs, and polystyrene, have been described (130—132). Vinyl acetate and vinyUdene cyanide form highly alternating copolymers. 

Ingestion. Ingestion, unless prompt first aid or medical treatment is given, is rapidly fatal 1 mg of cyanide per kilogram of body weight can be fatal. Immediate and repeated adininistration of emetics and regurgitation (if the victim is conscious), followed or accompanied by the first aid and medical treatments described below should be carried out. If the victim is unconscious, stomach lavage should be performed by a physician or trained personnel. 

Several procedures for making glutaric acid have been described in Organic Syntheses starting with trimethylene cyanide (28), methylene bis (malonic acid) (29), y-butyrolactone (30), and dihydropyran (31). Oxidation of cyclopentane with air at 140° and 2.7 MPa (400 psi) gives cyclopentanone and cyclopentanol, which when oxidized further with nitric acid at 65—75° gives mixtures of glutaric acid and succinic acid (32). 

ElectrolyticaHy generated hypochlorite may be used for the oxidative destmction of cyanides (qv) or the sterilization of domestic wastes. Several on-site systems for swimming pool sterilization and municipal waste treatment works have been developed. One of these systems is described in Reference 124. On-site production and immediate use of chlorine is considered safer than the transportation of chlorine. 

The method in the procedure differs from any previously described in that the sodium bisulfite addition product of benzal-dehyde is prepared in the presence of sodium cyanide and the nitrile is formed immediately. 

Methylsuccinic acid has been prepared by the pyrolysis of tartaric acid from 1,2-dibromopropane or allyl halides by the action of potassium cyanide followed by hydrolysis by reduction of itaconic, citraconic, and mesaconic acids by hydrolysis of ketovalerolactonecarboxylic acid by decarboxylation of 1,1,2-propane tricarboxylic acid by oxidation of /3-methylcyclo-hexanone by fusion of gamboge with alkali by hydrog. nation and condensation of sodium lactate over nickel oxide from acetoacetic ester by successive alkylation with a methyl halide and a monohaloacetic ester by hydrolysis of oi-methyl-o -oxalosuccinic ester or a-methyl-a -acetosuccinic ester by action of hot, concentrated potassium hydroxide upon methyl-succinaldehyde dioxime from the ammonium salt of a-methyl-butyric acid by oxidation with. hydrogen peroxide from /9-methyllevulinic acid by oxidation with dilute nitric acid or hypobromite from /J-methyladipic acid and from the decomposition products of glyceric acid and pyruvic acid. The method described above is a modification of that of Higginbotham and Lapworth. ... 

The procedure described is an example of a more general synthetic method for the direct conversion of ketones into cyanides. " The reaction has been carried out successfully with acyclic and cyclic aliphatic ketones, including numerous steroidal ketones and aryl-alkyl ketones. The conversion of diaryl or highly hindered ketones such as camphor and )3,j8-dimethyl-a-tetralone requires the use of a more polar solvent. The dimethoxyethane used in the present procedure should be replaced by dimethyl sulfoxide. ... 

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. 

Attempts to prepare aulfonyl cyanides from the corresponding sulfonyl chlorides according to the procedure described were unsuccessful when applied to mono-, di-, and trichloromethaneaulfonyl chloride, to dimethylsulfamoyl chloride, and to ethylene- and 2,4-diiiitrophenylsulfonyl chloride. 

The described method of preparation of w-nitrophenyl disulfide is essentially that of Foss and co-workers and is a modification of that reported by Ekbom. The disulfide has been prepared by reaction of potassium ethyl xanthate with w-nitrobenzenedi-azonium chloride solution, followed by hydrolysis to yield the mercaptan, which is subsequently oxidized with potassium ferro-cyanide or dilute nitric acid to the disulfide. ... 

Mandelic Acid.—The reaction furnishes a simple and general method for obtaining hydroxy-acids from aldehydes or ketones by the aid of the cyanhydrin. The formation of the cyanhydrin may be effected in the manner described or by the action of hydrochloric acid on a mixture of the aldehyde or ketone with potassium cyanide, or, as in the case of the sugais, by the use of liquid hydrocyanic acid and a little amme-nia. 

In a German patent issued in 1929, Bergs described a synthesis of some 5-substituted hydantoins by treatment of aldehydes or ketones (1) with potassium cyanide, ammonium carbonate, and carbon dioxide under several atmospheres of pressure at 80°C. In 1934, Bucherer et al. isolated a hydantoin derivative as a by-product in their preparation of cyanohydrin from cyclohexanone. They subsequently discovered that hydantoins could also be formed from the reaction of cyanohydrins (e.g. 3) and ammonium carbonate at room temperature or 60-70°C either in water or in benzene. The use of carbon dioxide under pressure was not necessary for the reaction to take place. Bucherer and Lieb later found that the reaction proceeded in 50% aqueous ethanol in excellent yields for ketones and good yields for aldehydes. ... 

Complexes 79 show several types of chemical reactions (87CCR229). Nucleophilic addition may proceed at the C2 and S atoms. In excess potassium cyanide, 79 (R = R = R" = R = H) forms mainly the allyl sulfide complex 82 (R = H, Nu = CN) (84JA2901). The reaction of sodium methylate, phenyl-, and 2-thienyllithium with 79 (R = R = r" = R = H) follows the same route. The fragment consisting of three coplanar carbon atoms is described as the allyl system over which the Tr-electron density is delocalized. The sulfur atom may participate in delocalization to some extent. Complex 82 (R = H, Nu = CN) may be proto-nated by hydrochloric acid to yield the product where the 2-cyanothiophene has been converted into 2,3-dihydro-2-cyanothiophene. The initial thiophene complex 79 (R = R = r" = R = H) reacts reversibly with tri-n-butylphosphine followed by the formation of 82 [R = H, Nu = P(n-Bu)3]. Less basic phosphines, such as methyldiphenylphosphine, add with much greater difficulty. The reaction of 79 (r2 = r3 = r4 = r5 = h) with the hydride anion [BH4, HFe(CO)4, HW(CO)J] followed by the formation of 82 (R = Nu, H) has also been studied in detail. When the hydride anion originates from HFe(CO)4, the process is complicated by the formation of side products 83 and 84. The 2-methylthiophene complex 79... 

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