| 摘要 |
The present invention relates to substantially pure piperidine derivative compounds of the formulae: wherein R<SUB>1 </SUB>is hydrogen or hydroxy; R<SUB>2 </SUB>is hydrogen; or R<SUB>1 </SUB>and R<SUB>2 </SUB>taken together form a second bond between the carbon atoms bearing R<SUB>1 </SUB>and R<SUB>2</SUB>; R<SUB>3 </SUB>is -COOH or -COOR<SUB>4</SUB>; R<SUB>4 </SUB>has 1 to 6 carbon atoms; A, B, and D are the substituents of their respective rings each of which may be different or the same and are hydrogen, halogens, alkyl, hydroxy, alkoxy, or other substituents. A process of preparing such piperidine derivative compounds in substantially pure form is also disclosed. |
