A series of pyrrolo [3, 2-c] quinoline derivatives were synthesised and evaluated as inhibitors of selected enzymes of the kynurenine pathway. 7-Chloro-3-methyl-1H-pyrrolo [3, 2-c] quinoline-4-carboxylic acid (7a) was found to be a relatively potent and selective inhibitor of kynurenine-3-hydroxylase (KYN-3-OHase). A molecular modelling study showed a good superimposition of 7a with PNU-156561 and kynurenine the natural substrate of ...