Organometallic compounds reactions with amides

Fig. 12. Reaction of organometallic compounds with nucleophilic sites (H-Nu) of the microbial cell. In this way organometallic compounds interfere with a large number of cell processes. For example, the reaction with essential thiol groups leads to the inhibition of enzymes. However, amines, amides, amino acids and sulphur-free proteins are nucleophilic reaction partners for organometallic compounds, too the corresponding reactions cause disturbances of many kinds in the metabolism of the microbe cell.

Nitriles are similar in some respects to carboxylic acids and are prepared either by SN2 reaction of an alkyl halide with cyanide ion or by dehydration of an amide. Nitriles undergo nucleophilic addition to the polar C=N bond in the same way that carbonyl compounds do. The most important reactions of nitriles are their hydrolysis to carboxylic acids, reduction to primary amines, and reaction with organometallic reagents to yield ketones. 

For a list of preparations of ketones by the reaction of organometallic compounds with carboxylic esters, salts, anhydyrides, or amides, with references, see Ref. 568, pp. 685, 693. 

Interest in the uses of HMPT has also been maintained, but a warning has been issued (by the E. I. du Pont de Nemours Company and the U.S. National Institute for Occupational Safety and Health) about its potential acute toxicity. HMPT has been used in the synthesis of 2,4-bis(dimethylamino)qui nolines,9 8 as a solvent for reactions between carbonyl compounds and sulphur," for the conversion of iV-benzylcarbox-amides into 3-phenylpropionitriles,100 in reactions between metals or organometallic compounds with a variety of organic substrates,101 and as a solvent for alkylation reactions of /J-keto-esters and related compounds in which the alkylation reaction is accompanied by de(alkoxycarbonylation) (Scheme 7).102... 

Lithium bis(trimethylsilyl)amide is a colorless solid which is soluble in a variety of organic solvents suitable for reactive compounds such as organometallic substances or substituted metal amides. The compound melts at 71 to 72°. It is unstable in air and catches fire when compressed, but it is stable in an atmosphere of nitrogen. Reactions with a variety of nonmetallic halides give lithium halides and hexamethyldisilazyl derivatives. 

This reaction can be initiated by strong bases (metal hydrides, alkali metals, metal amides, metal alkoxides, and organometallic compounds), protonic acids, or by water. Water is often used as the initiator (cf. Problem 10.7) for industrial polymerization of lactams and the process is referred to as hydrolytic polymerization. Anionic initiation with bases is preferred when polymerization is to be carried out in the mold itself for converting monomer directly into a molded object. Cationic initiation with acids, however, is not so useful because both the extents of conversion and polymer molecular weights are significantly lower (Odian, 1991). 

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