The 5-1ipoxygenase (5-LOX) inhibitors are expected to be useful for the treatment of allergy and asthma.Zileuton was the first 5-LOX inhibitor brought to market for the treatment of bronchial asthma.Pyridinothiazole derivatives were designed based on the structure ofZileuton,and synthesized and evaluated as 5-LOX inhibitors.Pyridinothiazoles were synthesized with cyclization of thiourea.Amino-hydroxypyridine was reacted with several substituted isothiocyanate to yield thioureas and pyridinothiazoles were synthesized in acid solvent.The synthesized compounds were evaluated in LTC4 formation inhibition test.Most of pyridinothiazole derivatives showed good biological activities.