| abstract |
Compounds of the formula <IMAGE> wherein R1 is hydrogen or alkyl of 1 to 4 carbon atoms; R2 is hydrogen, methyl or carboxyl; and A is pyridyl, benzodioxanyl or <IMAGE> where R3, R4 and R5, which may be identical to or different from each other, are each hydrogen, hydroxyl, alkoxy, alkyl, halogen, carboxyalkyl or nitro, or one of R3, R4 or R5 is dialkylamino, carboxamido, morpholino, piperidino, hydroxy-piperidino, cyano or phenyl; non-toxic salts thereof formed with an inorganic base when R1 is hydrogen and/or R2 is carboxyl; and non-toxic addition salts thereof formed with an organic base when R1 is hydrogen. The compounds are useful as antiallergics. |