Beilstein J. Org. Chem.2022,18, 1140–1153, doi:10.3762/bjoc.18.118
-Trisubstituted pyrrolidine-2,3-dione derivatives were prepared from the above mentioned 2-pyrrolidinone derivatives and aliphatic amines, which exist in enamine form and are stabilized by an intramolecular hydrogen bond. A possible reaction mechanism between 3-pyrroline-2-one and aliphatic amine (CH3NH2) was
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Keywords: 4-acetyl-3-hydroxy-3-pyrroline-2-ones; 1,5-dihydro-2H-pyrrol-2-ones; pyrrolidine-2,3-dione; 2-pyrrolidinone derivative; 3-pyrroline-2-one; Introduction
2-Pyrrolidone, also known as γ-lactam, is a five-membered heterocyclic ring containing four carbon and one nitrogen atoms [1]. This γ-lactam
-acetyl-3-hydroxy-3-pyrroline-2-ones via multicomponent reactions of ethyl 2,4-dioxovalerate with aromatic aldehydes, and aniline in glacial acetic acid. These 2-pyrrolidinone derivatives were then reacted with aliphatic amines in ethanol to obtain a library of 1,4,5-trisubstituted pyrrolidine-2,3-dione
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Graphical Abstract
Figure 1:
Structure of naturally occurring and synthetic 2-pyrrolidone derivatives.
Beilstein J. Org. Chem.2021,17, 1447–1452, doi:10.3762/bjoc.17.100
; pyrrolidine-2,3-dione; Introduction
The Michael reaction is a powerful reaction that has been so far applied for the formation of carbon–carbon and carbon–heteroatom bonds in organic synthesis [1][2]. After the renaissance of organocatalysis in the year 2000, this field has been applied tremendously for the
-dione 1b with a 4-methylbenzylidene-substituent provided the product 3o in 83% yield and 72% ee (Table 3, entry 1). A similar enantioselectivity was obtained with the 4-tert-butylenzylidene-substituted pyrrolidine-2,3-dione 1c (Table 3, entry 2). Then, different 4-halobenzylidene-substituted pyrrolidine
) derivatives (Table 3, entries 3–5). These products could be particularly useful for further transformations via cross-coupling reactions. The ortho-fluoroarylidene-substituted pyrrolidine-2,3-dione 1g also participated in the reaction to deliver product 3t in 86% ee (Table 3, entry 6). 2,4-Disubstitution at
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Graphical Abstract
Scheme 1:
Reactions of α-nitroketones with unsaturated pyrazolone and with 4-benzylidenepyrrolidine-2,3-dione....