Organic compounds -- part of the class 532-570 series – Organic compounds – Nitriles
Patent
1997-05-06
1998-07-14
Richter, Johann
Organic compounds -- part of the class 532-570 series
Organic compounds
Nitriles
558351, 562869, C07C25314, C07C25330
Patent
active
057806659
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/EP95/04463 filed on Nov. 14, 1995.
The present invention relates to an improved process for preparing halomethylbenzoyl cyanides of the general formula I which can, if required, also carry from 1 to 4 further radicals which are inert in the reaction, from halomethylbenzoyl chlorides of the general formula II converted by reaction with alkali metal or transition metal cyanides into the corresponding 2-halomethylbenzoyl cyanides I, and that the progress of the process can be beneficially influenced by adding a catalyst. Catalysts said to be suitable are the halides, cyanides, hydroxides, bisulfates, C.sub.1 -C.sub.4 -alkyl sulfates and tetrafluoroborates of quaternary nitrogen compounds, and aryl- and alkylphosphonium halides. However, the reactions indicated in the examples reveal that the yields are not entirely satisfactory for a reaction on the industrial scale.
It is an object of the present invention to remedy this deficiency.
We have found that this object is achieved by the present improved process for preparing the halomethylbenzoyl cyanides I, which comprises reacting II with a cyanide-donating compound in the presence of a Lewis acid, if required in an inert organic solvent or diluent, and then isolating the product.
The halomethylbenzoyl chlorides II can be prepared by known halogenation methods from the corresponding methyl-substituted benzene derivatives (for example, DE-A 28 35 440) or from the corresponding benzoic acids (for example, DE-A 40 42 282).
The process according to the invention is normally carried out under atmospheric pressure or slightly reduced pressure, generally at from -20.degree. to 100.degree. C., preferably 0.degree. to 80.degree. C., in particular 20.degree. to 80.degree. C.
Cyanide-donating compounds are, preferably, hydrogen cyanide, cyanohydrin, alkali metal cyanides such as sodium and potassium cyanides or transition metal cyanides such as mercury(I) cyanide, silver cyanide and copper(I) cyanide. Sodium cyanide is particularly expedient.
In general, the halomethylbenzoyl chloride II and the cyanide-donating compound are used in approximately stoichiometric amounts. However, an excess of cyanide, up to a 2-fold quantity, in particular a 1.05-1.5-fold quantity, based on the amount of II, is preferred.
Concerning the use of Lewis acids, reference may be made to Jerry March, Advanced Organic Chemistry, Fourth Edition 1992, pages 539-552, and the literature cited therein.
According to findings to date, particularly particularly suitable catalysts are tin tetrachloride, aluminum chloride, iron(II) chloride, iron(III) chloride, zinc chloride, titanium tetrachloride, boron trifluoride and antimony pentachloride, and tin tetrachloride and titanium tetrachloride are very particularly suitable.
The catalyst is preferably used in amounts of from 0.01 to 5 mol %, in particular from 0.1 to 3 mol %, based on the amount of II.
Where the halomethylbenzoyl chloride II is not in liquid form, it is advisable to add an inert organic solvent or diluent, in which case aprotic dipolar and non-polar solvents are particularly suitable.
Aprotic dipolar solvents are solvents in which a solvent molecule has a pronounced dipole moment but carries no hydrogen atoms capable of hydrogen bonding. The dielectric constant of such solvents is-greater than 15. Concerning the definition of aprotic dipolar solvents, reference may be made to A. J. Parker, Chem.
Rev. 69 (1969), 1-32, especially page 2.
Examples of suitable aprotic dipolar solvents are sulfoxides such as dimethyl sulfoxide, diethyl sulfoxide, dimethyl sulfone, diethyl sulfone, methyl ethyl sulfone and tetramethylene sulfone; nitriles such as acetonitrile, benzonitrile, butyronitrile, isobutyronitrile and m-chlorobenzonitrile; N,N-dialkyl-substituted carboxamides such as dimethylformamide, tetramethylurea, N,N-dimethylbenzamide, N,N-dimethylacetamide, N N-dimethylphenylacetamide, N,N-dimethylcyclohexanecarboxamide, N,N-dimethylpropionamide and homologous piperidide, morpholide and pyrrolidide of carboxylic acid
REFERENCES:
patent: 4455264 (1984-06-01), Findeisen et al.
patent: 4829085 (1989-05-01), Wenderoth et al.
patent: 5221762 (1993-06-01), Wingert et al.
patent: 5352826 (1994-10-01), Devic et al.
patent: 5446199 (1995-08-01), Isak et al.
Jerry March, Adv. Org. Chem. 4th Ed. 1992, pp. 539-552.
A.J. Parker, Chem. Rev. 69, 1-32 (1969).
Isak Heinz
Keil Michael
Wettling Thomas
Wingert Horst
Wolf Bernd
BASF - Aktiengesellschaft
Oswecki Jane C.
Richter Johann
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