Preparation of 2- and 4-(2-alkylcarbamoyl-1-methylvinyl)-7-alkyloxybenzo[b]furans having potent antagonistic activity against human leukotriene B4 BLT1 and/or BLT2 receptors
Preparation of 2- and 4-(2-alkylcarbamoyl-1-methylvinyl)-7-alkyloxybenzo[b]furans having potent antagonistic activity against human leukotriene B4 BLT1 and/or BLT2 receptors
(E)-2-Acetyl-4-(2-diethylcarbamoyl-1-methylvinyl)-7-(1-phenylethoxy)benzo[b]furan (4b) with a characteristic conformation and (E)-2-(2-morpholinocarbo-1-methylvinyl)-7-ethoxycarbopropoxybenzo[b]furan ((E)-3b) were prepared and evaluated for their leukotriene B4
(LTB4) antagonistic activity. Compound 4b showed potent antagonistic activity against human BLT1 and BLT2 receptors. Compound (E)-3b displayed selective BLT2 receptor antagonistic activity. Both compounds were inactive to cysteinyl LT receptors.
Variable benzo[b]furan derivatives having (E)- and (Z)-2-alkylcarbamoyl-1-methylvinyl groups at the 2-, 4- and 5-positions and a carboxylpropoxy or (1-phenyl)ethoxy group at the 7-position were prepared to find novel and selective leukotriene B4
(LTB4) receptor antagonists. (E)-2-(2-Diethylcarbamoyl-1-methylvinyl)-7-(1-phenylethoxy)benzo[b]furan (4v) showed selective inhibition to the human BLT2 receptor (hBLT2). On the other hand, (E)-2-acetyl-4-(2-diethylcarbamoyl-1-methylvinyl)-7-(1-phenylethoxy)benzo[b]furan (7v) inhibited both human BLT1 receptor (hBLT1) and hBLT2. The (E)-2-(2-diethylcarbamoyl-1-methylvinyl) group lay on approximately the same plane as the benzo[b]furan ring, whereas the (E)-4-(2-diethylcarbamoyl-1-methylvinyl) group had the torsion angle (45.7°) from the benzo[b]furan ring plane. However, the (Z)-(2-alkylcarbamoyl-1-methylvinyl)benzo[b]furans were inactive. The inhibitory activity depended on the conformation of the 2-diethylcarbamoyl-1-methylvinyl group.