Synthesis of isomeric 2,3,5‐trisubstituted perhydropyrrolo[3,4‐d]‐isoxazole‐4,6‐diones via 1,3‐dipolar cycloaddition reactions

Abstract

magnified image A series of isoxazolidine derivates (isomeric 2,3,5‐trisubstitutedperhydropyrrolo[3,4‐d]isoxazole‐4,6‐diones) used as anti‐inflammatory, immunosuppressive, antibacterial agent, and inhibitor for some enzymes were synthesized. These compounds were prepared by 1,3‐dipolar cycloaddition of N‐methyl maleimide and N‐phenyl maleimide with nitrones. Diastereomeric products obtained in this reaction were separated by column chromatography and recrystallized. All compounds synthesized were characterized by elemental analysis and spectroscopic methods (1H NMR, 13C NMR, and FTIR). J. Heterocyclic Chem., (2010).

2-Formylpyrroles as Building Blocks in a Divergent Synthesis of Pyrrolizines

“…The reaction of 8a with N-benzyl-N-hydroxylamine (9) afforded nitrone 10a in high yield as a stable yellow solid (Scheme 2). 19 Similar reaction of 5-formylpyrroles 8b-d with 9 efficiently proceeded to yield the tricyclic tetrahydro-1H-isoxazolo [3,4-a]pyrrolizines 11a-c, respectively. It is likely that these products were obtained by in situ generation of nitrones 10b-d, similar to that which occurred with the isolated nitrone 10a, followed by intramolecular 1,3-dipolar cycloaddition.…”

“…IR (film): 2948,1708,1624,1471,1438,1417,1328,1278,1169,1077,1028,968,929,851, 727 cm -1 . 21, 91 (19).…”

High diastereoselectivity induced by intermolecular hydrogen bonding in [3 + 2] cycloaddition reaction: experimental and computational mechanistic approaches

“…Cycloaddition reactions between acyclic/cyclic nitrones (azomethine‐ N ‐oxides) and N ‐aryl substituted maleimides have been studied extensively in the last 2 decades . As is well known aldonitrones may have 2 configurations that may interconvert.…”

“…A typical reaction between nitrone and N ‐substituted maleimide results in formation of fused 5 membered isoxazolidine cycloadduct. Generally, depending on the structure of the starting compounds, 2 diastereoisomers can occur, each with 2 enantiomers …”