5-Substituted pyranone compounds and their use as pharmaceuticals to treat an immediate hypersensitivity condition

摘要

Compounds are described of the formula <IMAGE> in which R1 is COOR5, CONHR5, cyano, 5-tetrazolyl or 5-tetrazolylaminocarbonyl, where R5 is hydrogen or C1-6 alkyl; R2 is hydrogen or C1-6 alkyl; R3 is a group of the formula R6-(Z)m- where m is O or 1, Z is O, S, SO, SO2 or CO, and R6 phenyl optionally substituted by one or more group selected from halogen, C1-4 alkyl, C3-6 cycloalkyl, C1-4 alkoxy, benzyloxy, hydroxy, nitro, C1-4 alkylthio, C1-4 alkylsulphinyl, C1-4 alkylsulphonyl, amino and NHR7 where R7 is C2-6 acyl; and R4 is hydrogen, C1-6 alkyl or halogen; and salts thereof. These compounds have pharmaceutical properties and in particular are useful in the treatment of immediate hypersensitivity conditions such as asthma.