2-氨基-1-甲基-1H-咪唑-5-羧酸乙酯的合成

Synthesis of 2-amino-1-methyl-1H-imidazol-5-carboxylic acid ethyl ester

以肌氨酸乙酯盐酸盐为起始原料,经氨酯交换反应、Claisen-Schmidt反应、合环反应共3步反应,得到目标产物2-氨基-1-甲基-1H-咪唑-5-羧酸乙酯(1),产物结构经^(1)H NMR确证。优化了反应条件:第一步,n_((肌氨酸乙酯盐酸盐))∶n_((K2)CO_(3))=1∶1.5,反应时间为8h,反应温度为25℃;第二步,n_((3))∶n_((NaH))=1∶1.2;第三步,n_((4))∶n_((NH2)CN)=1∶2.5,n_((4))∶n_((NaOAc))=1∶3.2,优化条件下的总收率为43.7%。此合成途径操作简便、产品质量好、总收率高,利于大量生产。

The target product 2-amino-1-methyl-1H-imidazol-5-carboxylic acid ethyl ester(1)was obtained from the sarcosine ethyl ester hydrochloride as the starting material through three steps of transesterification,Claisen-Schmidt reaction and cyclization reaction.The structure of the product was confirmed by ^(1)H NMR.The reaction conditions were optimized:in the first step,n_((Sarcosine ethyl ester hydrochloride))∶n_((K_2CO_3))=1∶1.5,reaction time 8h,reaction temperature 25℃;In the second step,n_((3))∶n_((NaH))=1∶1.2;In the third step,n_((4))∶n_((NH_2CN))=1∶2.5,n(3)∶n(NaOAc)=1∶3.2,the total yield under the optimum conditions was 43.7%.This synthetic route is easy to operate,with good product quality and high total yield,which is more conducive to mass production.