| Abstrakt: |
The direct annelation reaction of 4substituted 2aminolbenzylideneamino1Himidazoles 1 or 2amino1isopropylideneamino1Himidazole 8 with ethoxymethylenemalononitrile I gave successfully bicyclic imidazo1,2apyrimidine compounds 2and 9in high yields. The reactions of other ethoxymethylene compounds of lower reactivity, i.e., ethyl ethoxymethylenecyanoacetate II and diethyl ethoxymethylenemalonate III, with 2amino1Himidazoles under similar conditions afforded the corresponding enamines 3, 4and 10, which, upon heating in the presence of an acid or a base, could readily be cyclized to form imidazopyrimidines except for 1isopropylideneamino compound 10. In general, the 3phenyl compounds 3band 4b did not cyclize to the type 2compound resulting in a full recovery of the starting enamines. |
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