Based on the definitions of pharmacophore and privileged structure, outline essential structural features a 1,4-dihyrdopyridine must possess for effective Ca2+ channel blocking capability. (ex. functional groups, presence of electron-donating or electron-withdrawing moieties) 2. Why are the products of today's lab (dimethyl 1,4-dihydro-2,6-dimethylpyridine-3, 5-dicarboxylate and diethyl 1,4-dihydro-2,6-dimethylpyridine-3, 5-dicarboxylate) ineffective in this regard?