Synthesis of Nitrogen-Containing Heterocycles 12. Reactions of 2-Amino-1-benzylideneamino-1H-imidazoles with Dimethyl Acetylenedicarboxylate
作者:Yoshiko Miyamoto
DOI:10.3987/com-08-11558
日期:——
2-Amino-4-aryl-l-benzylideneamino-IH-imidazoles (1) reacted with dimethyl acetylenedicarboxylate (DMAD) in benzene to give dimethyl 2-amino-1-benzylidene-amino-1H-pyrrole-3,4-dicarboxylates (3), benzonitriles (4) and dimethyl 1-(2-amino-1-benzylideneamino-4-aryl-1H-imidazole-5-yl)fumarates (5) in moderate to high yields. Compounds 3 and 4 were considered as the reaction products of the intermediary Diels-Alder adducts, dimethyl 1-amino-3-aryl-7-benzylideneamino-2,7-diazabicylo[2.2.1]hepta-2,5-diene-5,6-dicarboxylates (2), which were not isolated and decomposed in a retro Diels-Alder reaction. The products 5 resulted from a Michael conjugate addition reaction of 1 to DMAD.
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。