An isoxazole strategy for the synthesis of 4-oxo-1,4-dihydropyridine-3-carboxylates

• Timur O. Zanakhov,
• Ekaterina E. Galenko,
• Mikhail S. Novikov and
• Alexander F. Khlebnikov

Beilstein J. Org. Chem. 2022, 18, 738–745, doi:10.3762/bjoc.18.74

• -triaryl-substituted and 1,2,5,6-tetrasubstituted nicotinates. Keywords: isoxazole; methyl nicotinate; molybdenum hexacarbonyl; 4-pyridone; ring expansion; Introduction Pyridine moieties are present in many natural products, drugs, pesticides and industrial materials. Pyridine fragments are used in drugs

• , Supporting Information File 1). Compounds 2 have several reactive centers that make them attractive starting materials for the synthesis of new libraries of 4-pyridone and pyridine derivatives (Scheme 6). The methoxycarbonyl group of compound 2c was selectively reduced to give 3-(hydroxymethyl)pyridin-4(1H

Rhodium-catalyzed C–H functionalization of heteroarenes using indoleBX hypervalent iodine reagents

• Erwann Grenet,
• Ashis Das,
• Paola Caramenti and
• Jérôme Waser

Beilstein J. Org. Chem. 2018, 14, 1208–1214, doi:10.3762/bjoc.14.102

• previously reported [13], 5-substituted pyridinone 5m could not be functionalized. Isoquinolone 7n was prepared in 82% yield. The methodology could also be applied to 4-pyridone in a moderate 57% yield for product 7o. Unfortunately, pyrazin-2-one 5p could not be functionalized. Modification of the

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

Synthesis of highly functionalized 2,2'-bipyridines by cyclocondensation of β-ketoenamides – scope and limitations

• Paul Hommes and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2016, 12, 1170–1177, doi:10.3762/bjoc.12.112

• oligomeric side products. The resulting primary condensation products contain a 4-hydroxy group in the newly formed pyridine ring that also exists as 4-pyridone tautomer making the identification and purification at this stage inconvenient. We therefore removed all volatile components from the crude products

Streptopyridines, volatile pyridine alkaloids produced by Streptomyces sp. FORM5

• Ulrike Groenhagen,
• Michael Maczka,
• Jeroen S. Dickschat and
• Stefan Schulz

Beilstein J. Org. Chem. 2014, 10, 1421–1432, doi:10.3762/bjoc.10.146

• derivatives streptazones B1 (1), B2 (2), C (3), the 4-pyridone derivative streptazone D (4) with a pentadienyl side chain, and streptazolin (5) (Figure 1) [8]. Streptazolin is produced by several streptomycetes [8][9][10][11][12], and is formed biosynthetically by a polyketide mechanism [13]. The respective

An efficient method for the construction of polysubstituted 4-pyridones via self-condensation of β-keto amides mediated by P₂O₅ and catalyzed by zinc bromide

• Liquan Tan,
• Peng Zhou,
• Cui Chen and
• Weibing Liu

Beilstein J. Org. Chem. 2013, 9, 2681–2687, doi:10.3762/bjoc.9.304

• 1a–1k could be easily converted into their corresponding 4-pyridone 2a–2k. All the reactions proceeded smoothly and afforded the desired product in good to excellent isolated yields (72–90%) in 4 h. This transformation appears quite tolerant with respect to the positions of the substituents on the

• In summary, we have established an improved efficient synthetic protocol for the synthesis of 4-pyridone derivatives by a sequence of intermolecular dehydration of β-keto amides in the presence of phosphorus pentoxide (P2O5), 1,3-acyl migration and intramolecular dehydration. Comparing to the similar

A practical two-step procedure for the preparation of enantiopure pyridines: Multicomponent reactions of alkoxyallenes, nitriles and carboxylic acids followed by a cyclocondensation reaction

• Christian Eidamshaus,
• Roopender Kumar,
• Mrinal K. Bera and
• Hans-Ulrich Reissig

Beilstein J. Org. Chem. 2011, 7, 962–975, doi:10.3762/bjoc.7.108

• acid (Procedure 4) Pyridone 22 (22 mg, 0.06 mmol) was dissolved in anhydrous CH2Cl2 (0.3 mL) and anhydrous pyridine (0.3 mL), and (S)-3,3,3-trifluoro-2-methoxy-2-phenylpropanoic acid (17 µL, 0.09 mmol) added. The mixture was stirred under an atmosphere of argon at r.t. for 16 h. After complete

Asymmetric aza-Diels- Alder reaction of Danishefsky's diene with imines in a chiral reaction medium

• Bruce Pégot,
• Olivier Nguyen Van Buu,
• Didier Gori and
• Giang Vo-Thanh

Beilstein J. Org. Chem. 2006, 2, No. 18, doi:10.1186/1860-5397-2-18

• highly efficient procedure for the synthesis of 2-substituted-2,3-dihydro-4-pyridone derivatives through the aza-Diels-Alder reaction under 'green chemistry' conditions. The reaction has been found to perform well at room temperature in ionic liquids using no Lewis acid catalyst or organic solvent.[30