Synthesis of nitrogen-containing heterocycles 10. Reaction of 2-amino-1<i>h</i>-imidazole derivatives with ethoxymethylene compounds
作者:Yoshiko Miyamoto
DOI:10.1002/jhet.5570390123
日期:2002.1
ethoxymethylenemalonate (III), with 2-amino-1H-imidazoles under similar conditions afforded the corresponding enamines 3, 4 and 10, which, upon heating in the presence of an acid or a base, could readily be cyclized to form imidazopyrimidines except for 1-isopropylideneamino compound 10. In general, the 3-phenyl compounds (3b and 4b) did not cyclize to the type 2 compound resulting in a full recovery of the
4-取代的2-氨基-1-亚苄基氨基-1 H-咪唑(1)或2-氨基-1-异亚丙基氨基-1H-咪唑(8)与乙氧基亚甲基丙二腈(I)的直接成环反应成功地制得了双环咪唑[1] ,2- a ]嘧啶化合物2和9的产率很高。其他较低反应性的乙氧基亚甲基化合物,即乙氧基亚甲基氰乙酸乙酯(II)和乙氧基亚甲基丙二酸二乙酯(III),与2-氨基-1 H-咪唑在相似条件下反应,得到相应的烯胺3、4和10,其在酸或碱的存在下加热时,可以容易地环化以形成咪唑并嘧啶,除了1-异亚丙基氨基化合物10。通常,3-苯基化合物(3b和4b)没有环化为2型化合物,导致起始烯胺的完全回收。