Aromatic cyanides

New PHB materials are composed of Zn-tetraben2oporphyrin—aromatic cyanide—poly (methyl methacrylate) (180) or of tetraphenylporphyrin derivatives dispersed in polymer matrices such as PMMA and polyethylene (181). A survey of such materials has been given (181). 

The formation of a DPP molecule was first reported in 1974 as a minor product in low yield from the reaction of benzonitrile with ethyl bro-moacetate and zinc. A fascinating study by research chemists at Ciba Geigy into the mechanistic pathways involved in the formation of the molecules led to the development of an efficient one-pot synthetic procedure to yield DPP pigments from readily available starting materials, as illustrated in Scheme 4.10. The reaction involves the treatment of diethyl succinate (1 mol) with an aromatic cyanide (2 mol) in the presence of a strong base. The reaction proceeds through the intermediate 88, which may be isolated and used to synthesise unsymmetrical derivatives. 

TEES is capable of treating several classes of organic compounds, including aliphatics, aromatics, chlorinated aliphatics and aromatics, polycyclic aromatics, cyanides, amines, phenolics, organic acids, and ketones. 

A general synthesis of pyrimidines 364 is the aluminium chloride-catalysed reaction of the azadienes 107 with aliphatic or aromatic cyanides (equation 148)180. 

From Aryl Cyanides Acid Nitriles),— The aromatic cyanides which were simply referred to as substitution products (p. 521) are, of course, like the aliphatic cyanides, nitriles of acids which they yield on hydrolysis. 

As a classical technique for the synthesis of aromatic cyanides treatment of the corresponding halides with CuCN has to be cited (Rosenmund-von Braun reaction). It is carried out at 15C1-250 C, either without any solvent at all, or using pyridine or quinoline, which also operate as complexing agents for the CuCN. Other heavy metal cyanides or hexacyanoferrates have been used in principle, but their... 

Under remarkably mild conditions aromatic cyanides can be prepared from halogen compounds with alkali metal cyanides in the presence of transition metal complexes. Complexes of palladium and nickel are particularly useful, for instance tetrakis(triphenylphosphine)palladium(0) (6), tris(triphe-nylphosphine)nickel(O) (7) or trun -dichlorobis(triphenylphosphine)nickel(II) (8 Scheme 7). 

Triaryl-l,3,5-oxadiazinium salts 1 are obtained as yellow or reddish pentachlorostannates by the reaction of aroyl chlorides with two equivalents of aromatic cyanides in the presence of tin(IV) chloride.57... 

Some nucleophiles (CN , CP, Br for example) are best added as Cu(I) derivatives a list of these arid others appears in Table 2.4. The aromatic cyanide (15) is most easily disconnected this way. 

For the preparation of aromatic cyanides from aromatic halides Rosenmund and von Braun introduced copper cyanide in place of the alkali cyanide the halide is warmed with copper cyanide, if necessary with addition of a little pyridine, at 150-250°. The reaction can be accelerated by small amounts of a nitrile or of copper sulfate.444... 

This reaction was initially reported by Gattermann in 1890. It is the preparation of aromatic halides or aromatic cyanides by decomposition of corresponding diazo salts in the presence of copper powder, in which copper powder is freshly obtained from a copper (II) sulfate aqueous solution. Therefore, it is generally known as the Gattermann reaction. Occasionally, it is also referred to as the Gattermann method. It should be pointed out that this reaction is almost equivalent to the Sandmeyer Reaction It is believed that a radical mechanism might be involved in this reaction, by which electron transfer occurs at the surface of metallic copper. However, this reaction is not applicable for the preparation of aromatic fluorides because HF exists as H2F2 and ionized as H+ and 10 2 . ... 

Sugano Y, Fujiwara K, Shiraishi Y, Ichikawa S, Hirai T (2013) Photocatalytic hydrodenitro-genation of aromatic cyanides on TiO loaded with Pd nanoparticles. Catal Sci Technol 3 1718-1724... 

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