2-乙氧基萘并吡喃并[2,3-d]嘧啶-4(3H)-酮的合成

Synthesis of 2-Ethanoxy Naphtha [1′,2′:5,6]pyrano[2,3-d]pyrimidin-4(3H)-one

以2-萘酚、氰乙酸乙酯、4-氯苯甲醛为原料,以六氢吡啶有机碱为催化剂,无水乙醇为溶剂,通过Knoevenagl-Cope缩合得到2-氨基-3-乙氧羰基-4-(4-氯苯基)萘并吡喃(1),1再与三苯基膦、六氯乙烷及三乙胺反应得到膦亚胺中间体(2)。2与4-氯苯基异氰酸酯在二氯甲烷的溶液中采用aza-Wittig反应,得到碳二亚胺(3)。3与乙醇反应,经乙醇钠催化关环,合成了2-乙氧基萘并吡喃并[2,3-d]嘧啶-4(3H)-酮。实验考察了反应温度、反应时间、溶剂诸因素对膦亚胺收率的影响。结果表明:在反应温度5℃、反应时间6 h、乙腈为溶剂的优化条件下,产物收率为87.8%。产物结构经IR、1H NMR、MS进行了表征。

2-Aminonaphtha[1′,2′：5,6]pyrano-3-carboxylate（1）,obtained from Knoevenagl-Cope condensation reaction of 2-naphthol,ethyl cyanoacetate and 4-chlorobenzaldehyde using hexahydropyridine as catalyst and absolute ethyl alcohol as solvent,reacted with triphenylphosphine,hexachloroethane and triethylamine to give iminophosphorane（2）.Further aza-Wittig reactions of 2 with phenyi isocyanate using dichloromethane as solvent gave carbodiimide（3）, which reacted with ethyl alcohol to give 2-ethanoxy-naphtha [1′,2′：5,6]pyrano[2,3-d]pyrimidin-4（3H）-one in the presence of EtONa.The factors influencing the synthesis were investigated and the best reaction conditions were found.The optimum conditions were：reaction temperature of 5 ℃,reaction time of 6 h,and acetonitrile as solvent.The yield reached 87.8%.The product compounds were identified by using IR,1H NMR and MS spectroscopy.