Psynthesis of a substituted cyclohexenone via Michael addition and intramolecular aldol condensation (Robinson annulation) of chalcone with ethyl acetoacetate / Nor Aisah Uzairi

Ethyl 6-(4-methoxyphenyl)-4-phenylcyclohex-3-en-2-one-l-carboxylate was synthesized through Michael addition and intramolecular aldol condensation (Robinson annulation) of 4-methoxychalcone with ethyl acetoacetate using a strong base, natrium hydroxyde (NaOH) as catalyst. 4-mthoxychalcone was first prepared by aldol condensation of 4-methoxybenzaldehyde and acetophenone. The percentage yield of 4- methoxychalcone was 98.65% and its melting point is 74-75°C. Then 4-Methoxychalcone was reacted with ethyl acetoacetate through Michael addition and aldol cyclization to form the final substituted cyclohexenone product in 79% yield. The melting point of the substituted cyclohexenone product is 108 - 110°C.