US 4,163,852 AGranted

Process for the preparation of tetrahydro-thieno[3,2-c]- and [2,3-c]pyridine derivatives

AssigneeParcor

InventorsGerard Ferrand, Jean-Pierre Maffrand

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Abstract

This invention relates to a process for the preparation of tetrahydro-thieno[3,2-c]pyridine derivatives of the formula ##STR1## AND THEIR ISOMERIC TETRAHYDRO-THIENO[2,3-C]PYRIDINE DERIVATIVES IN WHICH R.sub.1 represents hydrogen, a lower alkyl or alkoxy radical, an aryl radical or an aralkyl radical; R.sub.2 and R.sub.3 represent hydrogen, halogen, a lower alkyl or alkoxy group, a di(loweralkyl)amino, nitro, cyano or acetamido group or, together with the phenyl nucleus to which they are attached, form a polycyclic aromatic ring, comprising reacting a tetrahydrothieno[3,2-c]pyridine derivative of the formula: ##STR2## OR A DERIVATIVE OF ITS ISOMER, TETRAHYDRO[2,3-C]PYRIDINE, WITH FORMALDEHYDE H-CHO and a phenol of the formula: ##STR3##

Claims3

Dependent claims

Process for the preparation of derivatives selected from the group consisting of the tetrahydro-thieno(3,2-c)pyridine derivatives of the formula:

##STR14## and their isomeric pyridine derivatives of the formula:
##STR15## in which the hydroxyl radical is at the 2-position;
R.sub.1 is hydrogen;
R.sub.2 is hydrogen;
and R.sub.3 is selected from the group consisting of hydrogen, halogen, lower alkyl, lower alkoxy and nitro;
comprising reacting in an organic solvent at a temperature between 50.degree. C. and the boiling temperature of the solvent a derivative selected from the group consisting of the tetrahydro-thieno(3,2-c)pyridine derivatives of the formula:
##STR16## and their isomeric tetrahydro-thieno(2,3-c)pyridine derivatives of the formula:
##STR17## in which R.sub.1 is hydrogen, with formaldehyde and a phenol of the formula:
##STR18## in which R.sub.2 and R.sub.3 have the above-defined meanings, to give the desired derivative selected from the pyridine derivatives of the formulae (Ia) and (Ib).

6 more elements

Dependencies are inferred from the claim text.