| abstract |
1,3-dihydro-2H-imidazo[4,5-b]pyridin-2-ones having an aryl or heteroaryl group in the 6-position, useful as phosphodiesterase inhibitors, are prepared by reacting a 2-amino-5-(aryl or heteroaryl)pyridine-3-carboxylic acid with diphenylphosphoryl azide. The compounds are of the formula <IMAGE> where R1 and R3 are hydrogen or lower-alkyl, R5 is lower-alkyl or fluorinated lower-alkyl, and Ar is 4-or 3-pyridinyl, or N-oxides thereof, or phenyl or substituted phenyl. |