Process for the preparation of substituted thiopyran-1-oxides
AssigneeRhone-Poulenc Rorer S.A.
InventorsPhilippe Pitchen, Matthew Powers, Patrick Leon, Dominique Petre
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Abstract
A process is described for the preparation of a compound of formula (IX) from 4-hydroxybutyl 3-pyridyl ketone. The compound of formula (IX) is an intermediate useful in the preparation of (1R,2R)-2-(3-pyridyl)-N-alkyl-tetrahydro-2H-thiopyran-2-carbothioamide 1-oxides which possess useful pharmaceutical properties, for example anti-hypertensive properties. ##STR1##
Claims11
A process for the preparation of a compound of formula (IX) ##STR3## which comprises the following step sequence:
- a) reducing a compound of formula (XI) ##STR4## wherein R.sup.2 is a straight or branched C.sub.1-4 alkyl group or a salt or addition compound thereof using a chiral reducing agent or by biochemical reducing means to provide a compound of formula (X) ##STR5## wherein R.sup.2 is as defined previously;
- b) converting a compound of formula (X) to a compound of formula (XII) ##STR6## wherein R.sup.2 is as defined previously and R.sup.3 represents an alkyl- or arylsulphonyl group;
- and
- c) cyclising the so-formed (R) isomer of formula (XII) to provide the desired (S) isomer of formula (IX).
A process for the preparation of a compound of formula (IX) ##STR7## which comprises cyclising a compound of formula (XII) ##STR8## wherein R.sup.2 represents a straight or branched C.sub.1-4 alkyl group and R.sup.3 is an alkyl or arylsulphonyl group.
A process for the preparation of a compound of formula (X) ##STR9## wherein R.sup.2 represents a straight or branched C.sub.1-4 alkyl group, which comprises reducing a compound of formula (XI) ##STR10## wherein R.sup.2 is as defined previously, or a salt or addition compound thereof using a chiral reducing agent or by biochemical reducing means.
A compound of formula (X) ##STR11## wherein R.sup.2 is a straight or branched C.sub.1-4 alkyl group, and salts thereof.
A compound of formula (XII) ##STR12## wherein R.sup.2 is a straight or branched C.sub.1-4 alkyl group and R.sup.3 is alkyl-or arylsulphonyl, and salts thereof.
Dependencies are inferred from the claim text.