Patent ID: 6197960
Filing Date: 2001-03-06
Classification: C07C,C07D

Abstract:
A process for producing a piperidinecarbinol of general formula (2): ##STR12##wherein R.sup.1 is a hydrogen atom, a lower alkyl group or an aralkyl group, which comprises reduction of the cyano group of a cyanoglutaric acid compound of general formula (3): ##STR13##wherein each of R.sup.2 and R.sup.3 is a hydrogen atom, a lower alkyl group, an aryl group or an aralkyl group, and simultaneous intramolecular cyclization thereof to form either (a) a compound of general formula (1'): ##STR14##as a cis/trans mixture, followed by isomerization of said compound of general formula (1') to a compound of general formula (1) as a trans isomer, or (b) the compound of general formula (1) as a trans isomer directly: ##STR15##and reduction of the compound of general formula (1) in the presence of a hydride reductant or a metal hydride reductant to form said piperidincarbinol,and when R.sup.1 is not hydrogen, either (i) after said reduction of the compound of general formula (1), converting said piperidinecarbinol formed to a compound of said general formula (2) wherein R.sup.1 is a lower alkyl group or an aralkyl group, or (ii) before said reduction of the compound of general formula (1), converting the compound of general formula (1) to a compound wherein the hydrogen bonded to the piperidine nitrogen is replaced with a lower alkyl group or an aralkyl group, which group becomes R.sup.1 in general formula (2), wherein the reduction of the cyano group of the cyanoglutaric acid compound of general formula (3) is carried out under a pressure of less than 20 atmosphere (gauge pressure).