Organic compounds -- part of the class 532-570 series – Organic compounds – Amino nitrogen containing
Patent
1997-10-07
1999-07-27
O'Sullivan, Peter
Organic compounds -- part of the class 532-570 series
Organic compounds
Amino nitrogen containing
548243, 5483701, 558354, 564253, 564254, 564257, C07C24912
Patent
active
059292792
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a process for the preparation of largely-isomerically pure .alpha.-bisoximes of the formula Ia another and where the radicals have the following meanings: radical which can be bonded to the structure directly or via an oxygen, sulfur or nitrogen atom; haloalkyl, alkoxy, haloalkoxy, alkylthio, alkylamino, dialkylamino or cycloalkyl.
.alpha.-Bisoximes are disclosed in the literature as intermediates and as active compounds for the control of animal pests or harmful fungi (WO-A 95/18,789; WO-A 95/21,153; WO-A 95/21,154; WO-A 95/21,156; DE Appl. No. P 44 32 336.0; DE Appl. No. P 44 41 674.1).
Depending on the configuration of the double bond of the group R.sup.1 O--N.dbd.CR.sup.2 --, the active compounds described in general display different activity, the activity of those compounds customarily being higher in which the groups R.sup.1 O-- and R.sup.2 on the N.dbd.C bond are cis to one another. Taking this into account, it is proposed in the literature cited to separate the isomers from one another in conventional ways (eg. by chromatography). The separation of the desired isomer from a mixture of isomers has the disadvantage that a not inconsiderable part of expensive intermediates or final products remains unused because they are present in the wrong configuration.
The literature proposes processes for the isomerization of .alpha.-bisoximes, whose disadvantage is based on the fact that they are either restricted to oximes having specific (stable) radicals and/or General Chem. USSR 58/1 (1988), 181; Tetrahedron 41/22 (1985), 5181; J. Org. Chem. USSR 20 (1984), 135; J. Org. Chem. USSR 27/1 (1991), 97; J. Phys. Chem. 91/26 (1987), 6490; Recl. Trav. Chim. Pays-Bas 111/2 (1992), 79!.
The literature additionally describes the conversion of bisoximes into a 18(10) (1988), 975; Synth. Reakt. Inorg. Met.-Org. Chem. 11(7) (1981), 621; Spectrosc. Lett. 23(6) (1990), 713; Z. Anorg. Allg. Chem. 496 (1983), 197!. These processes, however, have the disadvantage that they can only be used with those compounds whose substituents are stable to acids.
In addition, the earlier application WO-A 95/21,153 describes the isomerization of the compound A to A' in ether with HCl in 75% yield. ##STR2##
It is an object of the present invention to provide a generally applicable process for the preparation of largely isomerically pure .alpha.-bisoximes of the formula Ia another, which is particularly applicable to those compounds in which the substituents R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are not stable to acids or contain groups which are not stable to acids.
We have found that this object is achieved by a process for the preparation of largely isomerically pure .alpha.-bisoximes of the formula Ia another, which comprises treating a mixture of the isomers of the .alpha.-bisoximes Ia and Ib ##STR3## with a Lewis acid in an organic solvent.
The largely isomerically pure .alpha.-bisoximes of the formula Ia can also be obtained by the process according to the invention if an .alpha.-bisoxime Ib in which the groups R.sup.1 O-- and R.sup.2 on the N.dbd.C bond are trans to one another is treated with a Lewis acid in an organic solvent.
Fundamentally, the process according to the invention can be carried out in all organic solvents or diluents which do not liberate protic acids with the Lewis acids used. Accordingly, aprotic organic solvents are preferably used.
Suitable solvents are, for example, aliphatic hydrocarbons such as pentane, hexane, heptane, cyclohexane and petroleum ether, aromatic hydrocarbons such as benzene, toluene, o-, m- and p-xylene, halogenated hydrocarbons such as methylene chloride, chloroform, 1,2-dichloroethane and chlorobenzene, ethers such as diethyl ether, diisopropyl ether, tert-butyl methyl ether, dioxane, anisole and tetrahydrofuran, and also dimethyl sulfoxide and dimethylformamide, particularly preferably aliphatic hydrocarbons such as pentane, hexane, heptane, cyclohexane and petroleum ether and aromatic hydrocarbons such as toluene and o-, m- and p-xylene. Mixtures of the so
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Hauser et al., J. Org. Chem., vol. 20, 1955 pp. 1491-1495.
J. Gen. Chem., USSR, 58(1), pp. 181-184 (1988).
Tetrahedron, 41/22, 5181, 1985.
J. Org. Chem., USSR, 20, 135 (1984).
J. Org. Chem., USSR 27/1, 97 (1991).
J. Phys. Chem., 91/26, 6490, (1987).
Recl. Trav. Chim. Pays-Bas, 111/2, 79 (1992).
Synth. Rea. Inorg. Met.-Org. Chem., 18(10), 975, (1988).
Z. Anorg. Allg. Chem., 496, 197, 1983.
Synth. Rea. Inorg. Met.-Org. Chem., 11 (7), 621, (1981).
Spectrosc. Lett., 23(6), 713, 1990.
Bayer Herbert
Benoit Remy
Gotz Norbert
Muller Ruth
Sauter Hubert
BASF - Aktiengesellschaft
O'Sullivan Peter
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