Percobaan Sintesis Senyawa 4‐(4‐fluorofenil)‐2,6‐dimetil‐1,4‐dihidropiridin 3,5‐dikarbaldehida dan 2,6‐dimetil‐4‐fenil‐1,4 dihidropiridin‐3,5-dikarbaldehida = Experimental Synthesis of 4‐(4‐fluorophenyl)‐2,6‐dimethyl‐1,4‐dihydropyridine-3,5‐dicarbaldehyde and 2,6‐dimethyl‐4‐phenyl‐1,4‐dihydropiridine‐3,5-dicarbaldehyde