Sandmeyer’s reaction

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)... 

Potassium cupro-cyanide is the most convenient form in which cuprous cyanide can be used in Sandmeyer s Reaction. It is prepared by adding an excess of potassium cyanide to copper sulphate solution, whereby the cupric cyanide which is formed immediately breaks down to give cuprous cyanide and cyanogen, and the cuprous cyanide then dissolves in the excess of potassium... 

Some of the cuprous chloride compounds of the diazonium salts have been isolated and analysed, and coirespond to the formula CoH.-.NjCl.CuoCIo (Hantzsch). The formation of a crystalline copper compound is rendeied very evident in the present preparation.. A modification of Sandmeyer s reaction IS the introduction of precipitated metallic copper in place of the cuprous salt (Gattermann). 

Sandmeyer s Reaction.—The ready formation of iodobenzene in the above method is due to the spontaneous decomposition of the diazonium iodide into iodobenzene and nitrogen... 

Cuprous Cyanide, Cu-(CN), while monnclinic crystals, insoluble in H 0, soluble in HCI. NHjOH. and potassium cyanide. Used in Sandmeyer s reaction to synthesize aryl cyanides. 

Cuprous Iodide, Cu.O. cubic while crystals, practically insoluble in H 0 or alcohol, soluble in NHjOH. potassium iodide, or potassium cyanide. Used in Sandmeyer s reaction lo synthesize aryl chlorides. Cupric Oxide. CuO, black cubic crystals, insoluble in IFO. soluble in HCI. NHjOH. or ammonium chloride. Used as a green and blue colorant in ceramics. 

Nitra-4 -chlorobenzonitrile, ndls, mp 100-1° was obtd by application of Sandmeyer s reaction, as above(Ref 2) ... 

Reaction LII. (b) Action of Cuprous Chloride on Nitro-diazonium Compounds. (B., 34, 3802 38, 725.)—Ordinarily when cuprous chloride acts on a diazonium salt in acid solution, a chloro-compound is the chief product (Sandmeyer s reaction, p. 345), and only a small quantity of the corresponding diphenyl compound is formed. But if a nitro-diazonium... 

Nitro-6-chlorohenzonitrile, ndls(from ale), mp 105-9° was prepd by treating 2-chlorobenzo-nitrile with mixed acid at RT(Ref 3) and 4 -Nitro-3-cblorobenzonitrile, ndls, mp 87° was obtd by Sandmeyer s reaction, as above(Refs 4 5 ) The expl props of the mononitro derivs were not detd... 

The Sandmeyer s reaction has been used many times for the synthesis of 2-nitroimidazole and many of its derivatives [335, 395, 406-413], Nucleophilic substitution of the diazo group has been used for the synthesis of derivatives of 5-nitroisothiazole [414] (Scheme 55). 

Sandmeyer s Reaction, 222. Saponification of ethyl malonlc ester, 162. 

Catalyzed one-electron transfers, possibly largely intramolecular in type e.g., Sandmeyer s reaction. 

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