The present invention relates to a compound of theformula:(see fig. I)wherein R1 is hydrogen or a lower alkyl; R2 is methylwhich is substituted by a carboxy, alkoxycarbonyl, cyano,halogen, aryl or heterocyclic group or C2-15 chain-likehydrocarbon residue having no lower alkyl at thea-position which may be substituted by a carboxy,alkoxycarbonyl, cyano, halogen, aryl or heterocyclicgroup; R3 is a lower alkyl; R4 is hydrogen or acyl; and R5and R6 each is a lower alkyl or lower alkoxy, or R5 and R6combinedly are butadienylene or a salt thereof.The compound (I) of the present invention has astrong 5- and 12-lipoxygenase inhibiting action, is ofhigh safety and is useful as, among others, an agent forameliorating circulatory system, an anti-allergic agentand a pharmaceutical agent for central nervous system
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