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Furandiones, alkaloids, Michael addition, decarboxylation, pyrrolizinones, pyrrolizinopyrrolizinones Therefore, compounds B 7 b are not formed by the well-known 1,4-Michael addition reaction of compounds B 6 b , as proven by the control experiment; they might, instead, be formed as the result of the addition of a second pyrrole ring to an intermediate at some stage (Scheme 5 B). Keywords: furandiones; alkaloids; Michael addition; decarboxylation; pyrrolizinones; pyrrolizinopyrrolizinones EN furandiones alkaloids Michael addition decarboxylation pyrrolizinones pyrrolizinopyrrolizinones 1265 1269 5 06/19/23 20230704 NES 230704 Pyrrolizinone, a bicyclic bridgehead-nitrogen skeleton, is valuable as a building block in medicinal chemistry and organic chemistry, because it can react with various nucleophiles at its C-1, C-2, or C-3 position, resulting in many useful synthetic and structural modifications. According to our previous experiences and our observations of the reaction, we propose the reaction mechanism for the formation of compounds B 6 b shown in Scheme 5 A. In the first step, a C-C bond is formed by a Michael addition through attack by the C-2 position of the pyrrole on the C-5 position of the furandione ( B A->B b ). [Extracted from the article]

N-Propargyl-2-aroylimidazoles synthesized and converted into the corresponding ketoximes. Under various conditions, several mono- and diketoxime imidazole derivatives were formed by converting the carbonyl or carbonyl and propargyl groups into oxime groups. N-Propargyl monooxime imidazole derivatives were cyclized by treatment with CuI to give various imidazopyrazine N-oxides. Several copper salts, such as CuOAc, CuSO4, and CuOTf, formed the same cyclization product. This cyclization reaction occurred only in the presence of Cu(I) or Cu(II) salts; other transition metals such as Au, Ag, In, and Fe did not yield cyclic products. The nucleus-independent chemical shift method was used to calculate the aromaticity of the bicyclic rings. [ABSTRACT FROM AUTHOR]