With cyanides

Alkylation and acylation of readily dissociable metal cyanides, e.g., alkali cyanides, lead almost exclusively to linkage of carbon to carbon, as in formation of nitriles671 or acyl cyanides,672 respectively, but undissociated cyanides can also be alkylated on nitrogen. 

To obtain isocyanides Gautier heated silver cyanide with 0.5-1.0 equivalent of alkyl iodide for several hours on a steam-bath for low-boiling alkyl iodides a pressure vessel is used. The mixture should not become brown in this reaction. The isocyanide is precipitated as a complex with silver cyanide, which, after removal of the excess of alkyl iodide by distillation, is decomposed by addition of a concentrated solution of potassium cyanide. The isocyanide can then be isolated by distillation. 

Detailed directions for preparation of ethyl isocyanide are to be found in Organic Syntheses.673 

Nitriles can be AT-alkylated and AT-acylated, to give nitrilium salts, in inert solvents containing complex-forming metal chlorides such as antimony(v) chloride and iron(m) chloride.674 These nitrilium salts afford JV-alkylated and A-acylated amides in high yields on alkaline hydrolysis.674 

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Figure 3-22 shows a nucleophilic aliphatic substitution with cyanide ion as a nucleophile, i his reaction is assumed to proceed according to the S f2 mechanism with an inversion in the stereochemistry at the carbon atom of the reaction center. We have to assign a stereochemical mechanistic factor to this reaction, and, clearly, it is desirable to assign a mechanistic factor of (-i-1) to a reaction with retention of configuration and (-1) to a reaction with inversion of configuration. Thus, we want to calculate the parity of the product, of 3 reaction from the parity of the... 

The cyanothiazoles are not obtained by replacement of a nuclear halogen with cyanide. 

Section 19 12 Nitnles which can be prepared from primary and secondary alkyl halides by nucleophilic substitution with cyanide ion can be converted to car boxyhc acids by hydrolysis... 

Section 20 18 Nitnles are prepared by nucleophilic substitution (8 2) of alkyl halides with cyanide ion by converting aldehydes or ketones to cyanohydrins (Table 20 6) or by dehydration of amides... 

The reaction of tert butyl chloride with cyanide ion proceeds by elimination rather than substitu tion... 

Reaction of chloroacetic acid with cyanide ion yields cyanoacetic acid [372-09-8] C2H2NO2, (8) which is used in the formation of coumarin, malonic acid and esters, and barbiturates. Reaction of chloroacetic acid with hydroxide results in the formation of glycoUc acid [79-14-1]. 

Sulfur dioxide is usefiil as a solvent for sulfur trioxide in sulfonation reactions for example, in the large-scale production of alkylbenzenesulfonate surfactant (329). A newer use for sulfur dioxide is in cyanide detoxification in connection with cyanide leaching of precious metals from mine dumps. 

The thiosulfate reaction with cyanide to give thiocyanate is the basis for the use of thiosulfate as an antidote in cyanide poisoning ... 

Zinc ores are generally floated at the mine (18). In the case of simple zinc sulfide ores, flotation is carried out by treatment with copper sulfate to activate the sphalerite causing it to be wet by the organic collector (eg, xanthate). The now-hydrophobic zinc ore particles attach themselves to the rising bubbles. Oxidized ore particles present must be sulftdized with sodium sulfide to be floated (19). Flotation produces concentrates which are ca 50—60% zinc. In mixed ore, the lead and copper are usually floated after depressing the sphalerite with cyanide or zinc sulfate. The sphalerite is then activated and floated. 

Cadmium is rapidly oxidized by hot dilute nitric acid with the simultaneous generation of various oxides of nitrogen. Unlike the ziac ion, the cadmium ion is not markedly amphoteric, and therefore cadmium hydroxide [21041-95-2] Cd(OH)2, is virtually iasoluble ia alkaline media. However, the cadmium ion forms stable complexes with ammonia as well as with cyanide and haUde ions. The metal is not attacked by aqueous solutions of alkaU hydroxide. 

These dyes aie prepared by the reaction of l-amino-4-nittoanthtaquinone-2-catboxylic acid amide (108) with cyanide in water (119). 

A very useful procedure for introducing a cyano group into a pyridazine ring is the Reissert-type reaction of the A/-oxide with cyanide ion in the presence of an acyl halide or dimethyl sulfate. The cyano group is introduced into the a-position with respect to the A-oxide function of the starting compound. The yields are, however, generally poor. In this way, 6-cyanopyridazines (111) can be obtained from the corresponding pyridazine 1-oxides (Scheme 33). 

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