Process for the preparation of thieno-pyridine derivatives

Process for the preparation of thieno-pyridine derivatives having the formula:

• ##STR62## in which R.sub.1 is a member selected from the group consisting of C.sub.1-7 alkyl;
• phenyl lower alkylene;
• phenyl lower alkylene in which the phenyl is substituted with 1 to 3 substituents selected from the group consisting of lower alkyl, hydroxy, lower acyloxy, lower alkoxy, nitro and halogen;
• naphthyl lower alkylene;
• thienyl lower alkylene;
• diphenyl lower alkylene;
• phenyl hydroxy-lower-alkylene;
• phenyl hydroxy-lower-alkylene in which the phenyl is substituted with 1 to 3 substituents selected from the group consisting of lower alkyl, hydroxy, lower acyloxy, lower alkoxy, nitro and halogen;
• naphthyl hydroxy-lower-alkylene;
• thienyl hydroxy-lower-alkylene;
• and diphenyl hydroxy-lower-alkylene;
• R.sub.2 is selected from the group consisting of hydrogen and lower alkyl;
• and R.sub.3 is hydrogen, comprising:
• (a) reacting a derivative having the formula:
• ##STR63## in which R.sub.2 and R.sub.3 are as defined for formula (I) and X is selected from the group consisting of hydrogen, an alkali metal and a radical MgY in which Y represents halogen, with a halosulfonyl derivative having the formula:
• Hal -- SO.sub.2 -- R.sub.4 (III)
• in which Hal represents halogen and R.sub.4 is selected from the group consisting of methane sulfonyl, trichloromethane sulfonyl, trifluoromethane sulfonyl, benzene sulfonyl, paratoluene sulfonyl, m. acetyl benzene sulfonyl and p. bromophenyl sulfonyl, to give a compound having the formula:
• ##STR64## (b) reacting said derivative (IV) with an amine of the formula
• R.sub.1 -- NH.sub.2 (V)
• in which R.sub.1 is as defined for formula (I), to give a compound having the formula:
• ##STR65## and (c) subsequently cyclising said derivative (VI) with formaldehyde to give the derivative of the formula (I).