Cyano compounds reviews

For a review of the acidity of cyano compounds, see Hibbert, F. in Patai Rappoport The Chemistry of Triple-bonded Functional Groups, pt. 1 Wiley NY, 1983, p. 699. 

The classic pyridine syntheses have been extensively reviewed by Abramovitch [24]. Many of them rely on the condensation of aldehydes or ketones with ammonia in the vapor phase. However, these processes suffer from unsatisfactory selectivity. Soluble organocobalt catalysts allow a selective one-step access to pyridine and a wide range of a-substituted derivatives from acetylene and the corresponding cyano compounds (eq. (2)). 

Ferris, J. and Hagan, W. J., Jr. (1984). HCN and chemical evolution the possible role of cyano compounds in prebiotic synthesis. Tetrahedron, 40, 1093 (review). 

Various aspects of the transition metal cyano complexes have been discussed in three authoritative reviews /, 76, 23). The present authors will therefore not attempt to give a comprehensive review of the subject. Instead, we restrict ourselves to the discussion of structural properties of crystalline cyano compounds containing octahedral M (CN)6 groups, where the characteristic construction element is given by the four-atomic sequence N—C—M . M represents a transition metal,... 

The ambident nature of the cyanide ion plays an important role in several crystalline cyano compounds which lie, however, outside the definition of compounds covered by this article. For a review of these structures the reader is referred to Ref. 23. 

The aim of this chapter is to present some recent and significant advances in the chemistry of polycyano compounds, especially from the last ten years. Only some patents will be mentioned. Dyes and other special compounds will not be discussed in detail. Literature on the subject that is already covered in reviews which have appeared since 1982 will only be referred to in connection with new results. A list of general reviews, which have been published on cyano compounds between 1981 and 1987, and short abstracts of their contents are given below as well as at the beginning of the sections dealing with malononitrile and with tetracyanoethylene ... 

The chemistiy of the cyano group has been reviewed up to about 1968 in an extensive monograph [1]. A short review of nitriles [2] and a comprehensive account of enaminonitriles and o-aminonitriles [3] have appeared more recently. Since 1968 a large number of reports have been published on new and improved methods of preparing cyano compounds this review surveys recent methods of preparing these important intermediates. 

As a class of compounds, nitriles have broad commercial utility that includes their use as solvents, feedstocks, pharmaceuticals, catalysts, and pesticides. The versatile reactivity of organonitnles arises both from the reactivity of the C=N bond, and from the abiHty of the cyano substituent to activate adjacent bonds, especially C—H bonds. Nitriles can be used to prepare amines, amides, amidines, carboxyHc acids and esters, aldehydes, ketones, large-ring cycHc ketones, imines, heterocycles, orthoesters, and other compounds. Some of the more common transformations involve hydrolysis or alcoholysis to produce amides, acids and esters, and hydrogenation to produce amines, which are intermediates for the production of polyurethanes and polyamides. An extensive review on hydrogenation of nitriles has been recendy pubHshed (10). 

As a class of compounds, the two main toxicity concerns for nitriles are acute lethality and osteolathyrsm. A comprehensive review of the toxicity of nitriles, including detailed discussion of biochemical mechanisms of toxicity and stmcture-activity relationships, is available (12). Nitriles vary broadly in their abiUty to cause acute lethaUty and subde differences in stmcture can greatly affect toxic potency. The biochemical basis of their acute toxicity is related to their metaboHsm in the body. Following exposure and absorption, nitriles are metabolized by cytochrome p450 enzymes in the Hver. The metaboHsm involves initial hydrogen abstraction resulting in the formation of a carbon radical, followed by hydroxylation of the carbon radical. MetaboHsm at the carbon atom adjacent (alpha) to the cyano group would yield a cyanohydrin metaboHte, which decomposes readily in the body to produce cyanide. Hydroxylation at other carbon positions in the nitrile does not result in cyanide release. 

For a review of complexes formed by tetracyanoethylene and other polycyano compounds, see Melby, L.R. in Rappoport The Chemistry of the Cyano Group, Wiley NY, 1970, p. 639. See also, Fatiadi, A.J. Synthesis, 1987, 959. 

Investigations of cyanides and cyano complexes of Cd and Hg have augmented tremendously since about 1990, after detection of inclusion compounds of Cd(CN)2. A thorough review on transition-metal cyanides especially emphasizes the chemistry of inclusion compounds of both the Hofmann type (frameworks dominated by planar Ni(CN)4 building blocks) and the cyanocad-mate type (frameworks with tetrahedral Cd(CN)4 units).87 The structures of these inclusion compounds, but also of cyanides themselves, often topologically resemble the structures of minerals this aspect ( mineralomimetic chemistry ) is dealt with in a simultaneous survey.88 A more generic review of framework structures, with a section on cyanide inclusion compounds, is also to be mentioned.90... 

It has been shown that when nucleophilic aromatic photo-substitution reactions are carried out in non-deoxygenated solutions of aprotic solvents, such as DMSO and acetonitrile, destructive superoxide anions may be formed from aromatic radical anions. Such solvents are best avoided. There has been a review of mechanistic aspects of photo-substitutions of the cyano group in aromatic compounds. ... 

Our review emphasizes three molecular systems 9,9 -bianthryl (BA) [30, 82, 88, 113-121], 4-(9-anthryl)-N,N-dimethylaminoaniline (ADMA) [122-130], and to a lesser extent the well known p-JV,IV-dimethylaminobenzonitrile (DMABN), a compound in the para-cyano-N,JV-dimethylaminoaniline class [1-5, 75-81, 131]. We only briefly mention the arylaminonaph-thalenesulfonates, which have recently been reviewed by Kosower and Huppert [4]. Brief mention is also made of picosecond experiments on diaminophenylsulphones and a number of other systems (see Section III.F). 

The first important MCR was developed by Strecker in 1850 (Scheme 1) [20]. In this reaction ammonia, an aldehyde and hydrogen cyanide combine to form a-cyano amines 1, which upon hydrolysis form a-amino acids 2. Also, heterocyclic compounds were obtained using MCRs. An example of this is the Hantzsch reaction, discovered in 1882 [21]. This reaction is a condensation of an aldehyde with two equivalents of a (3-ketoester in the presence of ammonia resulting in the formation of dihydropyridines 3. A comparable reaction is the Biginelli reaction, founded in 1893 ([22] and see for review [23]). This reaction is a 3-component reaction (3CR) between an aldehyde, a (3-ketoester and urea to afford dihydropyrimidines 4. 

The syntheses and biological activity of ring-A heterocyclic steroids have been reviewed. The JV-cyano-2-aza-A-norandrostane (333) was synthesized from the dibromo-seco-compound (331) via the JV-phenyl-2-aza-A-norandrostane (332) (Scheme 17). The mixture of iodoisothiocyanates (334) and (335) (see ref. 

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