440339-06-0Relevant academic research and scientific papers
Synthesis of nitrogen-containing heterocycles 10 [1]. Reaction of 2-amino- 1H-imidazole derivatives with ethoxymethylene compounds
Miyamoto, Yoshiko
, p. 157 - 162 (2007/10/03)
The direct annelation reaction of 4-substituted 2-amino-1-benzylideneamino-1H-imidazoles (1) or 2-amino-1-isopropylideneamino-1H-imidazole (8) with ethoxymethylenemalononitrile (I) gave successfully bicyclic imidazo[1,2-a]pyrimidine compounds 2 and 9 in high yields. The reactions of other ethoxymethylene compounds of lower reactivity, i.e., ethyl ethoxymethylenecyanoacetate (II) and diethyl 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 starting enamines.
