Summary: | Synthesis of cinnamic acid and its six derivatives has been done by employing Knoevenagel reaction. Benzaldehyde, 4-butylbenzaldehyde, 4-t-butylbenzaldehyde, 4-butoxybenzaldehyde, 4-phenylbenzaldehyde, 5bromo-2,4-dimethoxybenzaldehyde, and 5-bromo-2,3-dimethoxybenzaldehyde were reacted with malonic acid in pyridine - piperidine to give cinnamic acid (85,3%), 4-butylcinnamic acid (69,3%), 4-t-butylcinnamic acid (77,7%), 4butoxycinnamic acid (64,5%), 4-phenylcinnamic acid (65,5%), 5-bromo-2,4-dimethoxycinnamic acid (53,2%) and 5bromo-2,4-dimethoxycinnamic acid (57,2%), respectively. It was disclosed that 4-alkyl, 4-alkoxy, 4-aryl, dan 2-alkoxy groups decrease the reactivity of carbonyl carbon of benzaldehyde.
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Keywords: cinnamic acid, cinnamic acid derivatives, Knoevenagel reaction
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