Synthesis of extended fluorinated tripeptides based on the tetrahydropyridazine scaffold

• Thierry Milcent,
• Pascal Retailleau,
• Benoit Crousse and
• Sandrine Ongeri

Beilstein J. Org. Chem. 2024, 20, 3174–3181, doi:10.3762/bjoc.20.262

• could easily be synthesized under the same reaction conditions starting from the corresponding hydrazide amino acid. Compounds 3e and 3f were obtained as a mixture of conformers (1:1 ratio) which is often observed with N-acylhydrazones [29][30][31]. Indeed, in theory, N-acylhydrazones can exhibit four

Harnessing the versatility of hydrazones through electrosynthetic oxidative transformations

• Aurélie Claraz

Beilstein J. Org. Chem. 2024, 20, 1988–2004, doi:10.3762/bjoc.20.175

• synthesis of pyrazolo[4,3-c]quinoline derivatives 22 from 7-chloro-4-hydrazinoquinolines 20 and aromatic aldehydes 21 (Scheme 5) [40]. In 1992, Chiba and Okimoto reported the electrooxidative cyclization of aldehyde and ketone-derived N-acylhydrazones 23a and 23b to build 1,3,4-oxadiazoles 24a and Δ3-l,3,4

• -derived NH-acylhydrazones to build 1,3,4-oxadiazole derivatives in good yields. The electrolysis was conducted under galvanostatic conditions in methanol using a carbon graphite anode and a platinum cathode. From a mechanistic point of view, in situ condensation of acylhydrazines 28 with α-keto acids 27

• reactivity profile of hydrazones, the electrooxidative transformations of such a molecular building block provides a fascinating route to valuable compounds under mild and safe reaction conditions. Alone, the electrooxidation of NH-aryl, -tosyl, and -acylhydrazones triggered the cyclization of a radical

Construction of diazepine-containing spiroindolines via annulation reaction of α-halogenated N-acylhydrazones and isatin-derived MBH carbonates

• Xing Liu,
• Wenjing Shi,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 1923–1932, doi:10.3762/bjoc.19.143

• and proceeds through a by base-promoted annulation reaction of α-halogenated N-acylhydrazones and isatin-derived MBH carbonates. The reaction mechanism of this formal [4 + 3] annulation includes the in situ generated allylic ylide, nucleophilic substitution, Michael additon, and elimination processes

• -derived MBH carbonates with α-halogenated N-acylhydrazones for the convenient synthesis of functionalized spiro[indoline-3,5'-[1,2]diazepine] derivatives (reaction 5 in Scheme 1). Results and Discussion Initially, the reaction conditions were screened by employing α-chloro-N-benzoylhydrazone 1a and MBH

• [indoline-3,5'-[1,2]diazepines] 3a–m were obtained in reasonable to good yields. Both, α-chloro- and α-bromo-N-acylhydrazones could be successfully used in the reaction and gave similar results. Also, hydrazones with different benzoyl-protecting groups were well tolerated in the reaction. In general, α

Trifluoromethylated hydrazones and acylhydrazones as potent nitrogen-containing fluorinated building blocks

• Zhang Dongxu

Beilstein J. Org. Chem. 2023, 19, 1741–1754, doi:10.3762/bjoc.19.127

• in various pharmaceutical and agrochemical products. This review focuses on the reactivity, synthesis, and applications of fluoromethylated hydrazones and acylhydrazones. It summarizes recent methodologies that have been used for the synthesis of various nitrogen-containing organofluorine compounds

• . Keywords: acylhydrazones; difluoromethylation; dihydropyridazine; fluorinated building blocks; hydrazones; imidazolidines; pyrazoles; pyrazolidines; pyrazolines; trifluoromethylation; Introduction The introduction of fluorine into pharmaceuticals, agrochemicals, and materials can significantly enhance

• building blocks that have been used to construct organofluorine derivatives. To the best of our knowledge, the synthetic applications of fluoromethylated hydrazones and acylhydrazones as useful building blocks, has not yet been summarized. Hence, the present review highlights recent advancements enabling

Effects of the aldehyde-derived ring substituent on the properties of two new bioinspired trimethoxybenzoylhydrazones: methyl vs nitro groups

• Dayanne Martins,
• Roberta Lamosa,
• Talis Uelisson da Silva,
• Carolina B. P. Ligiero,
• Sérgio de Paula Machado,
• Daphne S. Cukierman and
• Nicolás A. Rey

Beilstein J. Org. Chem. 2023, 19, 1713–1727, doi:10.3762/bjoc.19.125

• Inorgânica, Universidade do Estado do Rio de Janeiro (UERJ), Rio de Janeiro, 20950-000, Brazil 10.3762/bjoc.19.125 Abstract N-Acylhydrazones are a versatile class of organic compounds with a diversity of potential applications. In this study, two new structure-related 3,4,5-trimethoxybenzoyl-containing N

• -acylhydrazones were synthesized and fully characterized, both in solution and in the solid state. The compounds differ with respect to the carbonyl precursors, i.e., 3-substituted salicylaldehydes with either a methyl or a nitro group. Single crystals of both compounds were isolated from the respective mother

• compounds are stable at physiological-like conditions, especially the methyl-derived one, which qualifies them for further toxicological and activity studies, such as those involving trivalent metal ions sequestering in the context of neurodegenerative diseases. Keywords: DFT calculations; N-acylhydrazones

Menadione: a platform and a target to valuable compounds synthesis

• Acácio S. de Souza,
• Ruan Carlos B. Ribeiro,
• Dora C. S. Costa,
• Fernanda P. Pauli,
• David R. Pinho,
• Matheus G. de Moraes,
• Fernando de C. da Silva,
• Luana da S. M. Forezi and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

• menadione (10) in trifluoroacetic acid under ethanol reflux conditions (Scheme 26) to synthesize acylhydrazones 81 in 63–91% yield. In view of the different structures that compounds 81a–e could adopt, after analysis by 2D NMR-NOESY spectra, it was found that all products were obtained as E-geometrical