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
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Graphical Abstract
Scheme 1:
Representative [4 + 3] cycloaddition reactions of MBH carbonates derived from isatins.
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
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
; phenol acidity; ring substituents; XRD; Introduction
N-Acylhydrazones are a class of compounds that contain the hydrazonic functional group (–NH–N=C–) attached to an acyl group, which can be modified to generate a range of different structures with varying properties [1]. The versatility of this class
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Graphical Abstract
Scheme 1:
Structure of (A) 3-methylsalicylaldehyde 3,4,5-trimethoxybenzoyl hydrazone (hdz-CH3) and (B) 3-nitr...