申请人:SUMITOMO CHEMICAL COMPANY, LIMITED
公开号:EP0435687A2
公开(公告)日:1991-07-03
Isomerization of an unsymmetrical ketoxime ether is effected using at least one Lewis acid selected from titanium chloride, titanium bromide, aluminium chloride, aluminium bromide, boron chloride, and boron bromide as isomerizing agents. Examples of the Lewis acid are titanium tetrachloride, titanium trichloride, aluminium trichloride, aluminium tribromide, boron trichloride, and boron tribromide. The ketoxime ether is preferably an anti-isomer or a syn-isomer of a compound represented by the formula (I) or a mixture of the anti-isomer and the syn-isomer:
wherein R¹ represents an aryl group, an aralkyl group or an alkyl group and R² and R³ each represents an aralkyl group or an alkyl group, with a proviso that R¹ and R² are not identical.
使用至少一种选自氯化钛、溴化钛、氯化铝、溴化铝、氯化硼和溴化硼的路易斯酸作为异构化剂,可实现不对称酮肟醚的异构化。路易斯酸的例子有四氯化钛、三氯化钛、三氯化铝、三溴化铝、三氯化硼和三溴化硼。酮肟醚最好是式 (I) 所代表化合物的反异构体或同异构体,或者是反异构体和同异构体的混合物:
其中 R¹ 代表芳基、烷基或烷基,R² 和 R³ 分别代表烷基或芳基,但 R¹ 和 R² 不完全相同。