Drug-induced modifications of the immune response. 12. 4,5-Dihydro-4-oxo-2-(substituted amino)-3-furancarboxylic acids and derivatives as novel antiallergic agents

The synthesis of a series of novel 4,5-dihydro-4-oxo-2-(substituted amino)-3-furancarboxylic acids, salts, esters, and amides is described. The title compounds when tested in the mediator-induced dermal vascular permeability and active anaphylaxis assays in rats demonstrated moderate to potent antiallergic activity. The [2-trans-(4-methylphenyl)cyclopropyl]amino analogue 53 emerged as the most active derivative. Thus, when administered intraperitoneally to rats at a dose of 100 mg/kg, it inhibited the action of the mediators serotonin, histamine, and bradykinin by 100%. In the active anaphylaxis assay in rats, compound 30 suppressed the edema by 81% at a dose of 100 mg/kg, following intraperitoneal administration.