✍ Scribed by Yoshiko Miyamoto
No coin nor oath required. For personal study only.
The direct annelation reaction of 4‐substituted 2‐amino‐l‐benzylideneamino‐1__H__‐imidazoles (1) or 2‐amino‐1‐isopropylideneamino‐1__H__‐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‐1__H__‐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.
📜 SIMILAR VOLUMES
## Abstract The reaction of __N__‐phenylimidoyl isoselenocyanates **1** with 2‐amino‐1,3‐thiazoles **10** in acetone proceeded smoothly at room temperature to give 4__H__‐1,3‐thiazolo[3,2‐__a__] [1,3,5]triazine‐4‐selones **13** in fair yields (__Scheme 2__). Under the same conditions, **1** and 2‐a
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