Patent EA-000404-B1 (EA)
Title: METHOD OF PREPARING ESSENTIALLY PURE ISOMERS OF alpha- BIS-OXIMES
Inventor: MULLER RUTH
IPC: C07C249/14
Filed: 1996-03-25
Abstract: 1.A method of preparing essentially pure isomers of α-bis-oximes of formula Ia R<1>O-N=CR<2>-CR<3>=N-OR<4>, in which the groups R<1>O- and R<2> are in the cis configuration with respect to the N=C bond, from a mixture of the cis and trans isomers (Ia and Ib), the various groups being defined as follows: R<1> and R<4> are hydrogen, or an organic carbon group; R<2> is hydrogen, cyano, nitro, hydroxy, amino, halogen or an organic group which may be bound directly or via an oxygen, sulphur or nitrogen atom to the main chain; R<3> is hydrogen, cyano, nitro, hydroxy, amino, halogen, alkyl, haloalkyl, alkoxy, haloalkoxy, alkylthio, alkylamino, dialkylamino or cycloalkyl, said method is characterised in that the mixture of isomers α-bis-oximes of formulas Ia and !b R<1>O-N=CR<2>-CR<3>=N-OR<4 >R<1>O-N=CR<2>-CR<3>=N-OR<4> "cis" "trans" Ia Ib   R<1>O-N=CR<2>-CR<3>=N-OR<4> < >R<1>O-N=CR<2>-CR<3>=N-OR<4> "cis" "trans" Ia Ib 2. The method of preparing essentially pure isomers of α-bis-oximes of formula Ib of Claim 1, characterized in that in which the groups R<1>O- and R<2> are in the trans configuration with respect to the N=C bond and is treated in an organic solvent with a Lewis acid. 3. The method of Claim 1, characterized in that for preparing essentially pure isomers of α-bis-oximes of formula Ia R<1>O-N=CR<2>-CR<3>=N-OR<4> Ia' in which the groups R<1>O- and R<2> and groups R<3> and -OR<4> are in the cis configuration with respect to the N=C bond, a mixture of the isomers of α-bis-oximes Ia and Ib. R<1>O-N=CR<2>-CR<3>=N-OR<4> R<1>O-N=CR<2>-CR<3>=N-OR<4> "cis" "cis" "trans" "cis" Ia Ib and is treated in an organic solvent with a Lewis acid. 4. The method of Claim 3, characterized in that α-bis-oximes of formula Ib R<1>O-N=CR<2>-CR<3>=N-OR<4> "trans" "cis" Ib in which the groups R<1>O and R<2> and are in the trans configuration with respect to the N=C bond, and groups R<3> and -OR<4> are in the cis configuration with respect to the N=C bond and is treated in an organic solvent with a Lewis acid. 5. The method of any preceding Claim, characterized in that aprotonic organic solvent is used in the process. 6. The method of Claims 1, 2 3 and 4, characterized in that the reaction is carried out in the range of -40 degree C to 150 degree C. 7. The method of Claims 1, 2 3 and 4, characterized in that halide of semimetal or metal of third or fourth main group, or transitional metal are used as the Lewis acid. 8. The method of Claim 7, characterized in that halide of boron, aluminum, tin, zinc, iron or titanium. Are used as the Lewis acid. 9. The method of Claim 7, characterized in that fluoride, chloride or bromide is used as halide. 10. The method of Claim 7, characterized in that fluoride, chloride or bromide of semimetal, or metal of third or fourth main group, or transitional metal are used as the Lewis acid. 11. The method of Claims 1, 2, 3 or 4, characterized in that AlCl3, AlBr3, FeCl3, BBr3, BCl3, BF3, SnCl4, ZnBr2 or TiCl4 are used as the Lewis acid. 12. The method of Claim 1, 2, 3 or 4, characterized in that toluene, methylchloride or tetrahydrofuran are used as organic solvent.