1,2,4-Triazolo[4,3-a]quinoxaline-1,4-diones as antiallergic agents

A series of new 1,4-dihydro-1,2,4-triazolo[4,3-]quinoxaline-1,4-diones has been prepared. These compounds were tested as inhibitors of antigen-induced release of histamine (AIR) in vitro from rat peritoneal mast cells (RMC) and as inhibitors of IgE-mediated rat passive cutaneous anaphylaxis (PCA). Most of this new class of antiallergic agents showed good activity in the RMC and PCA tests. The most potent compound, 2-acetyl-7-chloro-5-n-propyl-1,2,4-triazolo[4,3-a]quinoxaline-1,4-dione (1x), with an I50 value of 0.1 microM, is 30 times more potent than disodium cromoglycate (DSCG) in the RMC assay.