In a process for producing a nitrile compound from a corresponding aldehyde exhibited by the general formula (I) and a hydroxylamine inorganic acid salt or from an aldoxime exhibited by the general formula (II), (in the general formulas shown hereinabove, R.sup.1 represents an aryl group having 6 to 9 carbon atoms and R.sup.2 represents an alkyl or alkenyl group having 1 to 9 carbon atoms or an aryl group having 6 to 9 carbon atoms), a process, wherein water produced in the reaction is azeotropically distilled out of the reaction system with the aid of a solvent which makes an azeotropic mixture with water. The nitrile compound is useful as an important intermediate for the synthesis of pharmaceuticals or pesticides.
In preparing trifluoromethylbenzonitrile by reaction of trifluoromethylbenzaldehyde with hydroxylamine, the rate of reaction is enhanced and formation of trifluoromethylbenzamide is suppressed by carrying out the reaction in an organic solvent which is immiscible with water and has a sufficiently high boiling point, e.g. nitrotoluene, and continuously distilling by-produced water from the reaction system. The solvent can easily and almost entirely be recovered and reused.
A nitrile having formula (2): wherein R represents a substituted or unsubstituted alkyl, alkenyl, aralkyl or aryl group having 3 to 20 carbon atoms, is produced by a process, which comprises heating an aldoxime having formula (1): wherein R is as defined above, at 80 to 250.degree. C. in the presence of a catalyst (A) of an alkali metal or alkaline earth metal salt of a saturated or unsaturated mono- or dicarboxylic acid having 2 to 20 carbon atoms while removing product water from the reaction system by distillation.
A process for the preparation of a nitrile of formula ##STR1## wherein R is hydrogen, C.sub.1 -C.sub.4 alkyl or phenyl, by reaction of an aldehyde of formula ##STR2## wherein R is as defined above, with hydroxylamine sulfate and subsequent dehydration, which process comprises carrying out the reaction in propionic acid in the presence of a salt of propionic acid by heating to an external temperature in the range from 140.degree. to 165.degree. C., preferably from 150.degree. to 160.degree. C., for 2 to 6 hours, preferably for 3 to 5 hours, under atmospheric pressure, and simultaneously distilling the mixture of propionic acid and water from the system until a solution forms, and thereafter removing the mixture of propionic acid and water at 100.degree.-130.degree. C., preferably 110.degree.-120.degree. C., by vacuum distillation, and then isolating the resultant nitrile by standard procedures.
The present invention provides a process for producing a nitrile represented by the general formula (1): wherein R is alkyl, alkenyl, aralkyl or aryl, each may have a substituent, characterized by heating an aldoxime represented by the general formula (2): wherein R is as defined above, in the presence of one or more catalysts selected from hydroxides of alkali metals, alcoholates of alkali metals, hydroxides of alkaline earth metals and alcoholates of alkaline earth metals, and distilling off water formed in the course of the reaction from the reaction system. The process according to the present invention can produce a nitrile which is useful as a perfume or as a starting material for the organic synthesis of perfumes, medicines and so on in high yields and advantageously from the viewpoint of production economy.
New process for the synthesis of the .alpha.-(1-m.ethylethyl)-3,4-dimethoxyacetonitrile of formula (I): ##STR1## which is known as an intermediate in the synthesis of the drug internationally known as verapamil. The process starts from the isobutyryl-3,4-dimethoxybenzene of formula (II): ##STR2## which, by means of the Darzens condensation, gives an epoxyester which, by alkaline hydrolysis and subsequent decarboxylation, gives the .alpha.-(1-methylethyl)-3,4-dimethoxybenzeneacetaldehyde. This product is reacted with hydroxylamine to obtain the corresponding oxime that, by dehydration, gives the nitrile of formula I.
