One-Pot Synthesis of 1,4-Dihydropyridine Derivatives and Their X-Ray Crystal Structures: Role of Fluorine in Weak Interactions

1,4-dihydropyridines, namely diethyl 4-(4-fluorophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate (1a) , diethyl 2,6-dimethyl-4-(3,4,5-trimethoxyphenyl)-1,4-dihydropyridine-3,5-dicarboxylate (1b) , and diethyl 4-(3,4-dimethoxyphenyl)-2,6-dihydroxy-2,6-bis(trifluoromethyl)piperidine-3,5-dicarboxylate (2) , are synthesized by one-pot multicomponent condensation of aromatic aldehyde with ethyl acetoacetate and liquid ammonia in the presence of an ethanol-water mixture and are characterized by single crystal X-ray diffraction. The effect of a fluorine atom on the dihydropyridine nucleus give insight into the self-assembly of compounds with various types of non-covalent interactions that greatly affect the crystal packing.