Cyano-esters preparation

Substituted malonic acids are obtained by alkaline hydrolysis of alkyl-cyano esters prepared either by direct alkylation or by reduction of unsaturated cyano esters from the Knoevenagel reaction. ... 

The formation of ethyl cyano(pentafluorophenyl)acetate illustrates the intermolecular nucleophilic displacement of fluoride ion from an aromatic ring by a stabilized carbanion. The reaction proceeds readily as a result of the activation imparted by the electron-withdrawing fluorine atoms. The selective hydrolysis of a cyano ester to a nitrile has been described. (Pentafluorophenyl)acetonitrile has also been prepared by cyanide displacement on (pentafluorophenyl)methyl halides. However, this direct displacement is always aecompanied by an undesirable side reaetion to yield 15-20% of 2,3-bis(pentafluoro-phenyl)propionitrile. 

One alternative approach is to use photoisomerisable chiral compounds where the E and Z isomers have different helical twisting powers, e.g. menthone derivatives. By incorporating co-polymers, prepared from menthone containing monomers and cyano esters (5.5), as dopants into nematic LC mixtures materials, e.g. a mixture of cyanobiphenyls and cyanoterphenyls (E7 available from Merck), colour change can be effected by irradiating with UV light (365 nm). The colour obtained is dependent... 

The appropriate succinic acid can be prepared by condensation of the nnsntunitcd cyano ester with alcoholio potassium cyanide. 

This process was shown to be general, and a large family of substituted poly-p-xylylenes prepared in which X equals hydrogen, halogen, alkyl, cyano, ester, acyl, and other groupings. Advantages of this process (6, 7, 8, 9,10,11, 13) over previous routes (4) to poly-p-xylylene include... 

Cyclic derivatives having the A -acylenamines or N-acylimines structure can be prepared starting from the cyano esters as well as from the enol forms of / -ketonitriles. 

COOH — —CHO. This conversion can be effected in one flask by treatment of the carboxylic acid with N,N dimethylchloromethyleniminium chloride (prepared from DMF and oxalyl chloride) and pyridine to form a betaine, which is then reduced to the aldehyde by the hydride in the presence of a catalytic amount of Cul at — 78° The reaction is applicable to aliphatic and aromatic acids, and can tolerate halo, cyano, ester, and even carbonyl groups. Yields are usually —65-80%. 

A convenient procedure has been developed for the synthesis of cyano ester is prepared and treated with hydrogen cyanide in a single operation. For this purpose, a hot mixture of the carbonyl compound, cyanoacetic ester, and pyridyl acetate s treated with ethanol and potassium cyanide. 

Cyano acetals, preparation, 598 Cyanoacetic ester condensation, 608 Cyanoacetic ester synthesis, 429, 601 Cyano acids, esterification, 481 preparation, 593, 607, 608 preparations listed in table 74, 622 a-Cyano acids, decarboxylation, 429, 601... 

Nitriles are directly converted to esters by heating with an alcohol and sulfuric or hydrochloric acid. When water is absent, the imino ester salt is readily isolated (method 402). Aliphatic,aromatic, and heterocycliccyano compounds react in this manner. Most of the aromatic compounds contain a cyanomethyl group although the cyanide radical may be attached directly to the aromatic nucleus. Monosub-stituted malonic esters free from unsubstituted and disubstituted malonic esters are made from the corresponding a-cyano esters by this method. Malonic ester and disubstituted malonic esters have been similarly prepared. ... 

In efforts towards a synthesis of eremolactone, the dienolate (158) has been found to react with the cyano-ester (159) to give (160) (probable stereochemistry shown) most likely via a double Michael addition rather than a Diels-Alder reaction. Highly substituted cyclohexanes have been prepared by cycloadditions between cyclohexa-1,3-dienes and nitroso-compounds followed by N—O and olefinic bond cleavage (Scheme 12). ... 

Aminomethylation Reaction. The Hf(OTf)4-dopedMe3SiCl system was used as Lewis acid to catalyze the aminomethylation of electron-rich aromatic compounds. Suitable arenes include indoles, furans, pyrroles, thiophenes, and anilines, with new t)q)es of iV,0-acetals having a variety of functional groups, such as cyano, ester, bis(trimethylsilyl)amino, diallylamino, and cyclic amino moieties. This method allowed for the facile synthesis of nonnatural aromatic amino acid derivatives (eq 1). 4 Aminomethylation using a A, 0-acetal with a bis(trimethylsilyl)amino group was particularly successful in the direct preparation of a N-unsubstituted a-indolylglycine derivative, which required only a standard aqueous workup as the deprotective step. ... 

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). 

In addition to thiodiglycolic acid esters, the use of bis(cyanomethyl)sulfide in the Hinsberg reaction has facilitated the preparation of 5-cyano-thiophene-2-carboxamides. Thus, the condensation of biacetyl with bis(cyanomethyl)sulfide resulted in the efficient preparation of 10 (94% yield). 

---