吗啉催化“一锅法”合成3-甲基-5-苯基-2-环己烯酮

Morpholine Promoted One-pot Synthesis of 3-Methyl-5-phenylcyclohex-2-enone

以吗啉为催化剂,苯甲醛和乙酰乙酸乙酯为原料,采用"一锅法"合成了3-甲基-5-苯基-2-环己烯酮,并研究了吗啉的用量、碱和溶剂的种类、反应温度、反应时间等条件对该合成反应的影响。结果表明,当吗啉物质的量分数为苯甲醛的30%,以碳酸钾为碱,乙醇-水溶液(乙醇与水体积比为4∶1)为溶剂,于120℃温度下反应12 h,可得到3-甲基-5-苯基-2-环己烯酮的产率最高,为87%。产物结构经IR、1H NMR和13C NMR确证。反应历经了Robinson环合、水解、脱水、脱羧数个步骤,简化了合成操作。

A morpholine promoted one-pot reaction of benzaldehyde with ethyl acetoacetate leading to 3-Methyl-5-phenylcyclohex-2-enone is described.The effects of morpholine dosage,bases,solvents,reaction temperature and time on the conversion are studied,and the optimized conditions in which the yield of desired product is 87%are as follows:morpholine dosage is 30 mol%of benzaldehyde,with K 2CO 3 as a base,and ethanol-water(v/v=4/1)as solvent at ambient temperature overnight followed by 120℃for 12 h.The significance of our findings relates to the reduced manipulative procedure because the transformation is presumably through a Robinson annulation/hydrolysis/elimination/decarboxylation sequence.The product structure is confirmed by IR、1H NMR and 13 C NMR.