Biphenyl-4-ylcarbamoyl thiophene carboxylic acids as potent DHODH inhibitors.

A previously discovered DHODH inhibitor series was further improved by replacing the cyclopentene ring by aromatic heterocycles. Different isomers of these compounds were prepared by the directed ortho-metallation procedure. The compounds are more active than the corresponding cyclopentene analogs and show potent effects on PBMC's proliferation.