| abstract |
The present invention relates to substantially pure piperidine derivative compounds of the formulae: ##STR1## wherein R 1 is hydrogen or hydroxy; n R 2 is hydrogen; n or R 1 and R 2 taken together form a second bond between the carbon atoms bearing R 1 and R 2 ; n R 3 is --COOH or --COOR 4 ; n R 4 has 1 to 6 carbon atoms; n 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. n A process of preparing such piperidine derivative compounds in substantially pure form is also disclosed. |