at position 4 was replaced by a 1‐methyl‐4,5‐dichloroimidazolyl substituent, were synthesized and evaluated as calcium‐channelantagonists using the high K+ concentration of guinea‐pig ileum longitudinal smooth muscle. The structure of all compounds was confirmed by IR, 1H‐NMR, and mass spectra. The calcium‐channelantagonistactivity of compounds 10a–f demonstrated that compound 10b was the most active