Sodium cyanide conversion

In order to detect these elements in organic compounds, it is necessary to convert them into ionlsable inorganie substanees so that the ionic tests of inoiganio qualitative analysis may be applied. This conversion may be accomplished by several methods, but the best procedure is to fuse the organic compound with metallio sodium (Lassalgne s test). In this way sodium cyanide, sodium sulphide and sodium halides are formed, which are readily identified. Thus ... 

Dry potassium cyanide in sealed containers is stable for many years. An aqueous solution of potassium cyanide is slowly converted to ammonia and potassium formate the decomposition rate accelerates with increasing temperature. However, at comparable temperatures the rate of conversion is far lower than that for sodium cyanide only about 25% as great. 

It is good that we should be concerned about the environmental impact of what we, as chemists, do to our planet. But many environmental campaigners too easily confuse radioactive toxicity and chemical toxicity. For example, the radon gas emanating from naturally occurring granite rocks is chemically inert, because it is a rare gas, but it is toxic to humans because of its radioactivity. Conversely, sodium cyanide contains no radioactive constituents yet is chemically toxic. 

Erythrocyte suspension Sample purged absorption of hydrogen cyanide in sodium hydroxide conversion of thiocyanate to cyanide by potassium permanganate oxidation Spectrophotometry (thiocyanate- cyanide determination) No data 93-97 McMillan and Svoboda 1982... 

Baskin S, Kirby S. 1990. Effect of sodium tetrathionate on cyanide conversion to thiocyanate by enzymatic and non-enzymatic mechanisms [Abstract], The Toxicologist 10 326. 

Probably the most important group of phase transfer reactions, and certainly the commonest, are those in which an anion is transferred from the aqueous phase into the organic solvent, where nucleophilic substitution occurs. These would once have been performed in a dipolar aprotic solvent such as DMF. A good example is the reaction between an alkyl halide (such as 1-chlorooctane), and aqueous sodium cyanide, shown in Scheme 5.5. Without PTC, the biphasic mixture can be stirred and heated together for 2 weeks and the only observable reaction will be hydrolysis of the cyanide group. Addition of a catalytic amount of a quaternary onium salt, or a crown ether, however, will lead to the quantitative conversion to the nitrile within 2 h. 

The simplest C-C bond formation reaction is the nucleophilic displacement of a halide ion from a haloalkane by the cyanide ion. This was one of the first reactions for which the kinetics under phase-transfer catalysed conditions was investigated and patented [l-3] and is widely used [e.g. 4-12], The reaction has been the subject of a large number of patents and it is frequently used as a standard reaction for the assessment of the effectiveness of the catalyst. Although the majority of reactions are conducted under liquiddiquid two-phase conditions, it has also been conducted under solidrliquid two-phase conditions [13] but, as with many other reactions carried out under such conditions, a trace of water is necessary for optimum success. Triphase catalysis [14] and use of the preformed quaternary ammonium cyanide [e.g. 15] have also been applied to the conversion of haloalkanes into the corresponding nitriles. Polymer-bound chloroalkanes react with sodium cyanide and cyanoalkanes under phase-transfer catalytic conditions [16],... 

A more efficient and convergent industrial-scale synthesis that avoids toxic methyl iodide and sodium cyanide was developed (Scheme 15.2). Condensation of N,N-dimethyl-2,2-dimethoxyacetamide with imidazopyridine 7 under acidic conditions afforded hydroxy derivative 12. Conversion of the hydroxyl group to a chloride with thionyl chloride followed by reductive removal of the chloride with sodium borohydride provided zolpidem. 

The common route to phenylacetic acid is conversion of benzyl chloride into benzyl cyanide by reaction with sodium cyanide, followed by hydrolysis. 

Treatment of the dichloromethyl derivative 472 with sodium cyanide gave290 an almost quantitative yield of the epimeric nitriles (480, 481). The mixture could not he separated by chromatographic methods, but differences in reactivity of the stereoisomers towards methanolic hydrogen chloride allowed isolation of only one ester, namely, 482 the trails cyanide underwent ready conversion into the methyl ester, whereas the cis compound gave a rather complicated mixture of products, with amide 483 being identified as the major component. Reduction of the ester group in 482, followed hydrolysis of the dichloromethyl group, afforded DL-t/ireo-DL- Y/o-octose, characterized as the heptaacetate, and identified as threo-ido-octito by comparison with an authentic sample. 

A third route developed by this group started with the commercially available alcohol 32," a compound which has also been the subject of considerable process development due to its use as a common intermediate in the synthesis of several HMGR inhibitors.Conversion of 32 to the 4-halo or 4-nitrobenzenesulfonate 33 followed by displacement with sodium cyanide provided 34 in 90% yield, which is the z-butyl-ester analog of 29. It was noted that this procedure was most scaleable employing the 4-chlorobenzenesulfonate 33a due to the instability of the 4-bromo and 4-nitro-analogs to aqueous hydrolysis. Ra-Ni reduction as before provided the fully elaborated side-chain 35 as the f-butyl ester (Scheme 8). 

Conversion into 3-indolylacetic acid. In a 1-litre flask, fitted with a reflux condenser, place a solution of 35.2 g (0.72 mol) of sodium cyanide (CAUTION) in 70 ml of water, then add 25 g (0.144 mol) of gramine and 280 ml of 95 per cent ethanol. Boil the mixture under reflux for 80 hours. Dilute the cooled reaction mixture with 350 ml of water, shake with a little activated charcoal (e.g., Norit), filter and concentrate to about 350 ml under reduced pressure (water pump) in order to remove most of the alcohol. Cool to about 5 °C, filter off- the solid and wash it with a little cold water keep the filtrate (A). Recrystallise the solid from ethanol-ether to obtain 5.0 g (20%) of 3-indolylacetamide, m.p. 150-151 °C. 

EDTA. The manufacturing processes are all variations of the conversion of ethylenediamine to a cyanomethyl (-CH2CN) derivative and hydrolysis of this intermediate. Two processes go directly from ethylenediamine to the final product in a single step. They differ in that one used sodium cyanide (see Eq. 16.3) while the other used hydrogen cyanide and caustic soda (see Eq. 16.4)250. 

The Strecker synthesis is used to prepare amino acids in the laboratory. As shown in the following equation, an aldehyde is reacted with sodium cyanide and ammonium chloride in water to produce a cyanoamine. Conversion of the cyano group to a carboxylic acid completes the synthesis. Show the structure of the intermediate, A, in the following synthesis, and show the steps in the mechanism for the formation of A and for the conversion of A to the cyanoamine. (Hint Remember that NH4+ and H,0 are in equilibrium with NH3 and H-0+.)... 

The sodium cyanide solution added for the reaction is as follows (enough is always charged for 100 percent DCB conversion no matter what the actual conversion is) ... 

Brombenzyl cyanide was first prepared by Riener in 1881 by hrom-inating phenyl cyanide, and its manufacture in industry was commenced n 1914. Industrially, brombenzyl cyanide is prepared in three steals, as follows (1) chlorination of toluene to form benzyl chloride (2) the conversion of benzyl chloride to benzyl cyanide by the action of sodium cyanide in alcoholic solution (3) the bromination of the benzyl cyanide with bromine vapor in the presence of sunlight. 

Three tetracyclic systems, triphenylene, benz(c)phenanthrene and chrysene can be derived by angular benzannelation of phenanthrene and hence these hydrocarbons may be synthesized from corresponding phenanthreneacetonitriles. The phenanthrene-1-acetonitrile (81) used for the preparation of the chrysenes (82) was obtained from phenanthrene-l-carbonitrile (72a) in a sequence of conventional steps hydrolysis to the acid (84%) by KOH in triglycol, reduction to the carbinol (82%) by sodium dihydrido-bis(methoxyethoxy)aluminate, conversion by thionyl chloride in benzene to the chloromethyl derivative (98%), and finally reaction of the latter with sodium cyanide in DMSO to (81) (94%). 

For conversion of secondary alkyl chlorides to the corresponding cyanide the preferred solvent is dimethyl sulfoxide. The chloride is added slowly to a heated mixture of sodium cyanide and dimethyl sulfoxide, and heating is continued for 1-3 hrs. The reaction mixture is poured into water and the product extracted with chloroform or ether. After drying and removal of solvent, distillation gives the alkyl cyanide in yield of about 70%. 

In contrast to allyl halides substituted with one ASG, the cyclopropanation reaction proceeds relatively smoothly when a second ASG is present. Generally, the best results are obtained with sodium borohydride, sodium cyanide, potassium cyanide, and the sodium salts of alcohols or thiols as the nucleophilic species (Table 22, entries 3-26). Even spiroalkanes can be synthesized with the nucleophiles described above (Table 23). Examples illustrating this route are the conversion of a tetracyclic enamino ester with potassium cyanide to the corresponding electrophilic cyclopropane 2, and the facile one-pot synthesis of 1,1 -bis(hydroxymethyl)cyclo-propanes 3 by reduction of halogenated alkylidene malonates with lithium aluminium hydride. ... 

A related sequence is involved in the lithium aluminium hydride reduction of indol-3-yl-carbinols (which can be obtained from the corresponding ketones using milder reducing agents), with formation of the alkyl-indole. This constitutes a useful synthesis of 3-alkyl-indoles. The one-pot conversion of 3-formylindole into 3-cyanomethylindole with a mixture of sodium cyanide and sodium borohydride probably involves a comparable elimination from the cyanohydrin, then reduction. ... 

The 4,10,16-triaza-18-crown-6 macrocycle shown above was first prepared by Lehn and coworkers (Graf and Lehn, 1975 Lehn, 1985) and was an important intermediate for the synthesis of the first macrotetracyclic polyethers (Canceill et al., 1982 Kotzyba-Hibert et al., 1981 Pratt et al., 1988). The key step in this synthesis was conversion of A-tosyldiethanolamine [TsN(CH2CH20H)2] into the diacid dichloride, TsN(CH2CH20CH2C0Cl)2. As shown above, this conversion was accomplished by reaction with chlo-roacetic acid followed by oxalyl chloride (method A) (Miller et al., 1989) or by chloromethylation, sodium cyanide, hydrolysis and conversion of the diacid to the diacid dichloride (method B) (Graf and Lehn, 1981). The third hypothetical method to the diacid dichloride shown above starts with tosylamide and 5-chloro-3-oxa-l-pentanol followed by Jones oxidation and thionyl chloride (method C) (Qian et al., 1990). 

The most common agglomeration technology for the conversion of sodium cyanide into a safe product is briquetting with roller presses. Almond- or pillow-shaped compacts are made. The systems are completely enclosed, equipped with highly effective dust collection systems to safeguard the operators, and executed in stainless steel to keep corrosion in check. The discharge from the roller press is screened within the enclosed system, fines are recirculated internally to the briquetter feed bin, and dean product is immediately packed into sealed containers. 

---