Synthesis and Anti-inflammatory Activity of Novel Furochromenes

A series of variously substituted furochromenes, hemiacetals 2, acetals 3, and rearranged compounds 4, were synthesized from variously substituted 4-hydroxycoumarins and evaluated in several in vitro assays, inhibition of mast cell degranulation induced by the activation of FCE receptor type I or calcium ionophore and leukotriene B-4 (LTB4) inhibition. The most active derivatives, 3p and 4p (8-iso-propyl substitution in coumarin ring) and 3r (5-methyl-8-chloro substitution), showed significant inhibition of mast cell degranulation (Fc epsilon-triggered) and LTB4, and exhibited significant local anti-inflammatory activity in PMA induced ear edema in CD1 mice, with potency equal (compounds 3p and 4p) or better (compound 3r) in comparison with zileuton, a reference drug used. It might be a promising direction for developing novel drugs as potential agents for the treatment of allergies and other inflammatory diseases.