Pyridin-3-yl substituted ortho-fused pyrrole derivatives

A pyrrole derivative of the formula:

• ##STR27## in which (a) Y represents a carboxyl radical or a radical of the formula:
• ##STR28## in which R.sub.2 represents an alkyl or benzyl radical, A represents a sulphur atom, m represents 1, n represents zero, R represent pyridin-3-yl and R.sub.1 represents hydrogen;
• or (b) Y represents cyano, carboxyl, or a radical of the formula (II) as defined above, A represents sulphur, oxygen, or methylene, m represents 1 or 2 and n represents 0, 1 or 2, the sum of m+n being 1, 2 or 3, R represents hydrogen, alkyl, or phenyl, unsubstituted or substituted by halogen, alkyl, alkoxy or trifluoromethyl, and R.sub.1 represents a radical of the formula:
• ##STR29## in which p represents zero or 1, the said alkyl radicals or alkyl radicals or alkyl portions being straight-chain or branched-chain and containing 1 to 4 carbon atoms each and its addition salts with acids and, where they exist, its metal salts and its addition salts with nitrogen bases.