Process for preparing aryl-piperidine carbinols and novel intermediates used in the process
AssigneeBeecham Group Limited
InventorsErol A. Faruk, Roger T. Martin
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Abstract
A process is disclosed for the preparation of a compound of formula (I): ##STR1## wherein Ar is aryl or substituted aryl and R.sup.3 is hydrogen, alkyl or aralkyl, which process comprises reducing a compound of formula (II): ##STR2## wherein Ar and R.sup.3 are as defined with respect to formula (I) and R.sup.4 is alkyl. Compounds of formula (I) are useful as chemical intermediates.
Claims8
A process for the preparation of a compound of formula (I):
- ##STR12## wherein Ar is a group:
- ##STR13## in which X is hydrogen, alkyl having 1-4 carbon atoms, C.sub.1-6 alkoxy, trifluoro C.sub.1-6 alkyl, hydroxy, halogen, methylthio, or phenyl C.sub.1-6 alkoxy and R.sup.3 is hydrogen, C.sub.1-6 alkyl or phenyl C.sub.1-6 alkyl, which process comprises reducing a compound of formula (II):
- ##STR14## wherein Ar and R.sup.3 are as defined with respect to formula (I) and R.sup.4 is C.sub.1-6 alkyl.
(.+-.)-trans-3-Ethoxycarbonyl-4-(4'-fluorophenyl)-piperidin-2,6-dione, (.+-.)-trans-3-ethoxycarbonyl-4-(4'-fluorophenyl)-N-methyl piperidin-2,6-dione, or (.+-.)-trans-3-methoxycarbonyl-4-(4'-fluorophenyl)-piperidin-2,6-dione.
A process according to claim 4, wherein a compound of formula (III) as defined in claim 4 is condensed with a compound of formula (IV) as defined in claim 6 in a base/solvent system.
A process for the preparation of a compound of formula (I):
- ##STR18## wherein Ar is a group:
- ##STR19## in which X is hydrogen, alkyl having 1-4 carbon atoms, C.sub.1-6 alkoxy, trifluoro C.sub.1-6 alkyl, hydroxy, halogen, methylthio, or phenyl C.sub.1-6 alkoxy and R.sup.3 is hydrogen, C.sub.1-6 alkyl or phenyl C.sub.1-6 alkyl, which process comprises reducing a compound of formula (II):
- ##STR20## wherein Ar and R.sup.3 are as defined with respect to formula (I) and R.sup.4 is C.sub.1-6 alkyl, which is prepared by a process comprising (a) reacting a compound of formula (III):
- ##STR21## where R.sup.3 and R.sup.4 are defined with respect to formula (II), with a compound of formula (IV):
- ##STR22## wherein Ar is as defined with respect to formula (II) and OR.sup.5 is a leaving group, and/or (b) converting a compound of formula (II) wherein R.sup.3 is hydrogen to a compound of formula (II) wherein R.sup.3 is C.sub.1-6 alkyl or phenyl C.sub.1-6 alkyl.
Dependencies are inferred from the claim text.