Synthesis of sterically shielded piperidine nitroxides via acid-catalyzed heterocyclization of β-aminoketone derivatives with ketones

• Mark M. Gulman,
• Yurii I. Glazachev and
• Sergey A. Dobrynin

Beilstein J. Org. Chem. 2026, 22, 948–954, doi:10.3762/bjoc.22.74

• in materials science and structural biology. The new heterocyclization strategy implies the construction of a 2,2,6-trisubstituted piperidine scaffold from β-aminoketone acetals and dialkyl ketones under acid catalysis. The resulting amines were oxidized to the corresponding ketonitrones and

Inductive heating and flow chemistry – a perfect synergy of emerging enabling technologies

• Conrad Kuhwald,
• Sibel Türkhan and
• Andreas Kirschning

Beilstein J. Org. Chem. 2022, 18, 688–706, doi:10.3762/bjoc.18.70

• (25), formaldehyde (26), and aniline (27) and 10 mol % of the organocatalyst to yield β-aminoketone 28 in 85% yield (88% ee), in less than 1 h. Although a significantly higher yield was achieved compared to the batch experiment, a slight reduction in enantioselectivity was observed. The Petasis or

Recent progress in the synthesis of homotropane alkaloids adaline, euphococcinine and N-methyleuphococcinine

• Dimas J. P. Lima,
• Antonio E. G. Santana,
• Michael A. Birkett and
• Ricardo S. Porto

Beilstein J. Org. Chem. 2021, 17, 28–41, doi:10.3762/bjoc.17.4

• bromide provided ketones (+)-99 and (+)-100, in diastereoisomeric excess of about 92%. N-sulfinyl-β-aminoketone ketal (+)-99 was subjected to Mannich cyclization, via treatment with 25 equivalents of ammonium acetate in acetic acid at 75 °C, generating (−)-euphococcinine (2) in 90% yield. A similar

Synthesis of 3-(quinolin-2-yl)- and 3,6-bis(quinolin-2-yl)-9H-carbazoles

• Yang Li and
• Wentao Gao

Beilstein J. Org. Chem. 2010, 6, 966–972, doi:10.3762/bjoc.6.108

• : acetylcarbazole; β-aminoaldehyde; β-aminoketone; Friedländer condensation; sodium ethoxide; Introduction Nitrogen-containing heterocycles are a very important group of organic compounds because of their wide application in medicine, agriculture, and technology. Among these, quinoline and carbazole derivatives

• reaction between the readily available 3-acetyl-9-ethyl-9H-carbazole (1) or 3,6-diacetyl-9-ethyl-9H-carbazole (4) and β-aminoaldehydes or β-aminoketone (2a–c) as shown in Scheme 1. The starting materials 1 and 4 of our study were readily prepared according to the methods described in literature [35]. For

• 9-ethyl-3-(quinolin-2-yl)-9H-carbazoles and 9-ethyl-3,6-bis(quinolin-2-yl)-9H-carbazoles might be synthesized. Indeed, this was found to be the case as shown in Scheme 1. The Friedländer condensation reaction of 3-acetyl-9-ethyl-9H-carbazole (1) with 1 molar equivalent of β-aminoaldehydes or β