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# Details for Patent: 6,797,826

Title: | Piperidine derivatives and process for their production |

Abstract: | The present invention relates to substantially pure piperidine derivative compounds of the formulae: ##STR1## wherein R.sub.1 is hydrogen or hydroxy; R.sub.2 is hydrogen; or R.sub.1 and R.sub.2 taken together form a second bond between the carbon atoms bearing R.sub.1 and R.sub.2 ; R.sub.3 is --COOH or --COOR.sub.4 ; R.sub.4 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. |

Inventor(s): | D'Ambra; Thomas E. (Wynantskill, NY) |

Assignee: | AMR Technology, Inc. (Manchester, VT) |

Filing Date: | Sep 04, 2002 |

Application Number: | 10/235,052 |

Claims: | 1. A process of preparing a piperidine derivative compound of the formula: ##STR42## said process comprising: acylating a starting compound of the formula: ##STR43## with a compound of the formula: ##STR44## under conditions effective to produce a first mixture of regioisomers of the formula: ##STR45## hydrolyzing the first mixture of regioisomers under conditions effective to form a second mixture of regioisomers of the formula: ##STR46## recovering from the second mixture of regioisomers a para-regioisomer of the formula: ##STR47## halogenating the para-regioisomer under conditions effective to form an intermediate compound of the formula: ##STR48## reacting the intermediate compound with a piperidine compound of the formula: ##STR49## under conditions effective to form the piperidine derivative. 2. The process according to claim 1, wherein said recovering comprises: crystallizing from the second mixture of regioisomers a regioisomer salt of the formula: ##STR50## wherein X.sup.+ is cinchonidine; isolating the regioisomer salt; and converting the regioisomer salt to the regioisomer of the formula: ##STR51## 3. The process according to claim 1 further comprising: reducing the piperidine derivative under conditions effective to form a hydroxylated piperidine derivative of the formula: ##STR52## 4. A process of preparing a piperidine derivative compound of the formula: ##STR53## said process comprising: acylating a starting compound of the formula: ##STR54## with a compound of the formula: ##STR55## under conditions effective to produce a first mixture of regioisomers of the formula: ##STR56## hydrolyzing the first mixture of regioisomers under conditions effective to form a second mixture of regioisomers of the formula: ##STR57## recovering from the second mixture of regioisomers a para-regioisomer of the formula: ##STR58## halogenating the para-regioisomer under conditions effective to form a first intermediate compound of the formula: ##STR59## treating the first intermediate compound under conditions effective to form a second intermediate compound of the formula: ##STR60## reacting the second intermediate compound with a piperidine compound of the formula: ##STR61## under conditions effective to form the piperidine derivative. 5. The process according to claim 4, wherein said recovering comprises: crystallizing from the second mixture of regioisomers a regioisomer salt of the formula: ##STR62## wherein X.sup.+ is cinchonidine; isolating the regioisomer salt; and convening the regioisomer salt to the regioisomer of the formula: ##STR63## 6. The process according to claim 4 further comprising: reducing the piperidine derivative under conditions effective to form a hydroxylated piperidine derivative of the formula: ##STR64## 7. The process according to claim 6 further comprising: treating the hydroxylated piperidine derivative under conditions effective to form a piperidine derivative of the formula: ##STR65## 8. A process of preparing a piperidine derivative compound of the formula: ##STR66## said process comprising: acylating a starting compound of the formula: ##STR67## with a compound of the formula: ##STR68## under conditions effective to produce a first mixture of regioisomers of the formula: ##STR69## hydrolyzing the first mixture of regioisomers under conditions effective to form a second mixture of regioisomers of the formula: ##STR70## recovering from the second mixture of regioisomers a para-regioisomer of the formula: ##STR71## halogenating the para-regioisomer under conditions effective to form a first intermediate compound of the formula: ##STR72## treating the first intermediate compound under conditions effective to form a second intermediate compound of the formula: ##STR73## reacting the second intermediate compound with a piperidine compound of the formula: ##STR74## under conditions effective to form the piperidine derivative. 9. The process according to claim 8, wherein said recovering comprises: crystallizing from the second mixture of regioisomers a regioisomer salt of the formula: ##STR75## wherein X.sup.+ is cinchonidine; isolating the regioisomer salt; and converting the regioisomer salt to the regioisomer of the formula: ##STR76## 10. The process according to claim 8 further comprising: reducing the piperidine derivative under conditions effective to form a hydroxylated piperidine derivative of the formula: ##STR77## 11. The method according to claim 10 further comprising: treating the hydroxylated piperidine derivative under conditions effective to form a piperidine derivative of the formula: ##STR78## |