Nitriles, synthesis involving

The nitrile functional group is, formally, a dehydrated primary amide. (In fact, u little-used nitrile synthesis involves amide dehydration ... 

The Gewald aminothiophene synthesis involves the condensation of aldehydes, ketones, or 1,3-dicarbonyl compounds 1 with activated nitriles such as malononitrile or cyanoacetic esters 2 and elemental sulfur in the presence of an amine to afford the corresponding 2-aminothiophene 3. ... 

Adams and Slack s second isothiazole synthesis involved the preparation of j3-iminothiobutyramide (9) from the nitrile 8 and cycliza-... 

Sandmeyer s valuable isatin synthesis involves the removal of sulphur from diphenylthiourea (I) (p. 169) with basic lead carbonate. Hydrogen cyanide is combined with the reactive diphenylcarbodiimide (II) so obtained, and the nitrile (III) produced is converted by means of hydrogen sulphide into tbe thioamide (IV). Concentrated sulphuric acid brings about ring closure and the product is the a-anil of isatin (V). Then, by hydrolysis with dilute sulphuric acid, aniline is removed ... 

Eully hydroxylated 1,4-iminopolyols have been obtained using cis-4-oxyisoxa-zolines. This synthesis involves nitrile oxide cycloaddition to furan followed by various oxidative transformations of the C2 enol ether portion of the resulting furoisoxazoline cycloadducts (21,82,293,294) (see Section 6.4.3). 

In this context it is interesting to note that benzonitrile, Ph—C=N, trimerizes to a triazine on a Raney nickel surface. It was assumed that Jt-bonded nitriles were involved in the reaction mechanism.10 This reaction resembles the well-known template synthesis of phthalocyanine complexes from phthalodinitrile. Formation of linear polymers [—C(R)—N—] occurs on heating aryl or alkyl cyanides with metal halides.11... 

Kozikowski s group has been particularly active in the application of the INOC reaction toward the construction of a variety of natural products. One of the many examples from his laboratory involves the synthesis of tetracyclic compounds possessing suitably functionalized C rings for elaboration to a diverse number of ergot alkaloids via the INOC reaction. A total synthesis of chanoclavine I (65) was accomplished by this chemistry (Scheme 15). The key step in the synthesis involved the conversion of the nitro group of indole (62) into the corresponding nitrile oxide using the phenyl isocyanate procedure developed by Mukaiyama.57 The major product corresponded to isoxazoline (64). The isoxazoline nucleus was converted into chanoclavine I (65) in a series of subsequent steps. The application of nitrile oxide cycloaddition chemistry to the construction of other natural products can be expected to be an active area in future years. 

Nitriles and nitrilium salts, heterocyclic synthesis involving. 6, 95... 

The amino nitrile synthesis is particularly useful for the preparation of 2-amino-2-deoxy derivatives of rare sugars which would be difficult to obtain as intermediates in a synthesis involving animation alone. Thus, 2-amino-2-deoxy-L-glucose and 2-amino-2-deoxy-L-mannose can be prepared in good yield from the readily available L-arabinose.11,18... 

The other important isoxazole synthesis involves the concerted [3+2] cycloaddition reaction of nitrile oxides 4.18 with either alkynes 4.19 or alkyne equivalents 4.20. 

Synthesis of Amides Amides are the least reactive acid derivatives, and they can be made from any of the others. In the laboratory, amides are commonly synthesized by the reaction of an acid chloride (or anhydride) with an amine. The most common industrial synthesis involves heating an acid with an amine (at high temperatures, in the absence of oxygen) to drive off water and promote condensation. This simple industrial technique rarely works well in the laboratory, but it may succeed with the use of a coupling reagent (Section 24-11). Esters react with amines and ammonia to give amides, and the partial hydrolysis of nitriles also gives amides. 

Nitriles and nitrilium salts, heterocyclic synthesis involving, 6, 95 Nitro-compounds, heteroaromatic, ring synthesis of, 25, 113 Nitrogen-bridged six-membered ring systems, 16, 87... 

Pyrazolines. The synthesis involves oxidation of hydrazones to nitrile imines by Hg(OAc)j and in situ capture by alkenes. 

Nitrile synthesis. A method for the conversion of aldehydes into nitriles involves formation of the N,N-dimethylhydrazone (1), reaction with methyl iodide (or methyl... 

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