PIPERIDINE DERIVATIVES AND PROCESS FOR THEIR PRODUCTION

1 - 31 . (canceled)

32 . A process of preparing a compound of formula I:

R 1 is hydrogen or hydroxy;

R 2 is hydrogen;

or R 1 and R 2 taken together form a second bond between the carbon atoms bearing R 1 and R 2 ;

R 3 is —COOH or —COOR 4 ;

R 4 is an alkyl of 1 to 6 carbon atoms;

said process comprising:

acylating a starting compound of formula II:

wherein

R 5 is —SR 6 and

R 6 is an alkyl of 1 to 6 carbon atoms

with a compound of formula III:

under conditions effective to produce a first mixture of regioisomers of formula IV:

hydrolyzing the first mixture of regioisomers of formula IV under conditions effective to form a second mixture of regioisomers of formula V:

recovering from the second mixture of regioisomers of formula V the regioisomer of formula VI:

converting the regioisomer of formula VI to the compound of formula I with a piperidine compound of formula VII:

33 . A process according to claim 32 , wherein said recovering comprises:

crystallizing a regioisomer salt of formula VIII:

wherein X + is a Lewis Acid

from the second mixture of regioisomers of formula V;

isolating the regioisomer salt of formula VIII; and

converting the regioisomer salt of formula VIII to a regioisomer of formula VI:

34 . A process according to claim 33 , wherein X + is an alkali metal salt or an ammonium salt of the form NR 7 R 8 R 9 wherein R 7 , R 8 , and R 9 is hydrogen or a straight or branched alkyl of 1 to 6 carbon atoms, or an alkyl substituted at any position with a phenyl ring or a substituted phenyl ring.

35 . A process according to claim 34 , wherein X + is cinchonidine.

36 . A process according to claim 32 , wherein said acylating is carried out by a Friedel-Crafts reaction using AlCl 3 .

37 . A process according to claim 32 , further comprising:

reducing the compound of formula I under conditions effective to form a compound of formula IX:

38 . A process according to claim 37 , wherein the compound of formula IX is:

39 . A process according to claim 32 , wherein said converting comprises:

hydrohalogenating a regioisomer of formula X:

under conditions effective to form a first intermediate compound of formula XI:

wherein

X is a halogen and

reacting the first intermediate compound of formula XI with the piperidine compound of formula VII:

under conditions effective to form the compound of formula I:

40 . A process according to claim 32 , wherein said converting comprises:

reacting a regioisomer of formula X:

with the piperidine compound of formula VII:

under conditions effective to form the compound of formula I:

41 . A process according to claim 32 , wherein the compound of formula I is: