硼酸树脂的制备及其催化Biginelli反应性能研究

Preparation of Boric Acid Resin and Its Catalytic Performance Evaluation on the Biginelli Reaction

以苯乙烯、二乙烯基苯和4-乙烯基苯硼酸为原料,AIBN为引发剂,合成了含有硼酸基团的树脂,其活性硼酸基团含量可通过制备工艺调节。采用频哪醇吸附法,测定所合成树脂的活性硼酸基团含量,最高可达0.562 mmol/g。选取了几种活性硼酸基团含量较高的硼酸树脂催化Biginelli反应,优化了Biginelli反应条件。结果表明,以活性硼酸基团含量为0.486 mmol/g的硼酸树脂为催化剂,乙腈为溶剂,在催化剂的用量为0.412 g/(1 mmol乙酰乙酸乙酯),回流36 h的条件下,催化乙酰乙酸乙酯、苯甲醛和尿素的Biginelli反应,分离产率高达71%。催化剂反复使用多次,仍具有一定的催化活性。该方法也适用于不同取代基的芳醛、2-噻吩甲醛或硫脲,以中等产率得到一系列3,4-二氢嘧啶-2-酮类衍生物(DHMPs)。

The resin containing boric acid group was synthesized using styrene,divinylbenzene and 4-vinylphenylboric acid as the starting materials and AIBN as the initiator.The content of active boric acid groups could be tuned by adjusting the preparation process.The content of active boric acid groups of the as-synthesized resin is up to 0.562 mmol/g,as determined by Pinna alcohol adsorption method.Several boric acid resins with high content of active boric acid groups were selected to catalyze the Biginelli reaction,and the reaction conditions were optimized.The results showed that the Biginelli reaction of ethyl acetoacetate,benzaldehyde and urea was catalyzed by boric acid resin with active boric acid group content of 0.486 mmol/g.Under the optimized conditions,0.412 g/(1 mmol ethyl acetoacetate)of catalyst dosage,acetonitrile as solvent and reflux for 36 h,the product was isolated in a yield of 71%.The resin can be recycled and reused for several times with limitede decrease in activity.The method is also suitable for aromatic aldehydes with different substituents,2-thiophene formaldehyde and thiourea,and a series of 3,4-dihydropyrimidine-2-ketone derivatives(DHMPs)can be obtained in a moderate yield.