Solvent-induced E/Z(C=N)-isomerization of imines of some hydroxy-substituted formylcoumarins

Traven, V. F.; Иванов, И. В.; Панов, Алексей Валерьевич; Safronova, O. B.; Чибисова, Т. А.

doi:10.1007/s11172-008-0267-5

Cited by 15 publications

(4 citation statements)

References 11 publications

(4 reference statements)

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“…When we compare two chemically different group of compounds, namely derivatives of salicylaldehyde (10)(11)(12)(13) and coumarin derivatives (18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28) in context of their anticancer activity, we can take some general conclusions. Schiff bases derived from salicylaldehyde are effective in pancreas and cervical cancer cells; however, they demonstrate also…”

Section: Cytotoxicitymentioning

confidence: 99%

Design, synthesis, and biological activity of Schiff bases bearing salicyl and 7-hydroxycoumarinyl moieties

et al. 2019

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18 (11 novel) Schiff bases, derivatives of salicylaldehyde, 2-hydroxyacetophenone, and 6-acetyl-, 8-acetyl-, and 8-formyl-7-hydroxy-4-methylcoumarin were synthesized and characterized by their spectral studies. 6-Acetyl-7-hydroxy-4-methylcoumarin was prepared by novel method under microwave assistance. These Schiff bases were evaluated for antibacterial activities against 12 bacterial and six fungi strains in vitro. N-(3,5-Dichloro-2-hydroxybenzylidene)-4-aminobenzenesulfonic acid sodium salt proved to be the most active against Staphylococcus aureus and MRSA strains (MIC 0.0194 µmol/cm 3). The substitution pattern, two chlorine atoms in the salicylidene ring and the SO 3 Na group, is probably the most beneficial for the activity against Gram-(+) bacteria strains. All Schiff bases were evaluated for cancer efficacy against CFPAC-1 and HeLa cell cultures originating from human pancreas cancer or human cervical cancer. Schiff bases derived from salicylaldehyde are highly effective in pancreas and cervical cancer cells; however, they demonstrate also substantial toxicity towards NIH3T3 cells. Derivatives of coumarin contain three highly selective compounds: 7-hydroxy-8-[(4-methoxyphenylimino)methyl]-4-methyl-2H-chromen-2-one, N-[(7-hydroxy-4-methyl-2-oxo-2H-chromen-8-yl)methylene]-4-aminobenzenesulfonic acid sodium salt, and 7-hydroxy-8-[1-(4-hydroxyphenylimino)ethyl]-4-methyl-2H-chromen-2-one suggesting more promising potential of the second group of substances.

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Section: Cytotoxicitymentioning

confidence: 99%

Design, synthesis, and biological activity of Schiff bases bearing salicyl and 7-hydroxycoumarinyl moieties

et al. 2019

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“…Intermediate 27 , whose difluoromethylene warhead is positioned near the internal H-bond between the protonated imine and oxygen anion (Scheme ), was proposed to be the active Michael acceptor for the inactivation process. Surprisingly, the h OAT- 14 complex demonstrates that the newly formed covalent linkage has been moved to the phosphate side (Figure ), suggesting an imine isomerization − of the intermediate during the inactivation process. Arg413 is known to form a salt bridge with Glu235 before binding dicarboxylic substrates ( l -Glu or α-KG), as shown in the crystal structures of native h OAT (Figure S11A) and inactivated h OAT (Figure S11B/C).…”

Section: Resultsmentioning

confidence: 99%

Remarkable and Unexpected Mechanism for (S)-3-Amino-4-(difluoromethylenyl)cyclohex-1-ene-1-carboxylic Acid as a Selective Inactivator of Human Ornithine Aminotransferase

et al. 2021

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Human ornithine aminotransferase (hOAT) is a pyridoxal 5′-phosphate (PLP)-dependent enzyme that was recently found to play an important role in the metabolic reprogramming of hepatocellular carcinoma (HCC) via the proline and glutamine metabolic pathways. The selective inhibition of hOAT by compound 10 exhibited potent in vivo antitumor activity. Inspired by the discovery of the aminotransferase inactivator (1S,3S)-3-amino-4-(difluoromethylene)cyclopentane-1-carboxylic acid (5), we rationally designed, synthesized, and evaluated a series of six-membered-ring analogs. Among them, 14 was identified as a new selective hOAT inactivator, which demonstrated a potency 22× greater than that of 10. Three different types of protein mass spectrometry approaches and two crystallographic approaches were employed to identify the structure of hOAT-14 and the formation of a remarkable final adduct (32′) in the active site. These spectral studies reveal an enzyme complex heretofore not observed in a PLP-dependent enzyme, which has covalent bonds to two nearby residues. Crystal soaking experiments and molecular dynamics simulations were carried out to identify the structure of the active-site intermediate 27′ and elucidate the order of the two covalent bonds that formed, leading to 32′. The initial covalent reaction of the activated warhead occurs with *Thr322 from the second subunit, followed by a subsequent nucleophilic attack by the catalytic residue Lys292. The turnover mechanism of 14 by hOAT was supported by a mass spectrometric analysis of metabolites and fluoride ion release experiments. This novel mechanism for hOAT with 14 will contribute to the further rational design of selective inactivators and an understanding of potential inactivation mechanisms by aminotransferases.

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“…The relaxation back to E proceeds through the inversion transition state (as predicted by the theoretical calculations, Figure 3), in which energy does not depend on the solvent polarity. The process of cis/trans isomerization has been already described in structural analogues of 6 by Traven and coauthors [110,111]. A very recent study by Tang and co-workers describes the breakage of the CO-O bond in alcohols under strong external irradiation [112] in 4.…”

Section: Structurementioning

confidence: 88%

Ground-State Tautomerism and Excited-State Proton Transfer in 7-Hydroxy-4-methyl-8-((phenylimino)methyl)-2H-chromen-2-one as a Potential Proton Crane

Nedeltcheva-Antonova,

Antonov

2024

Physchem

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The tautomerism in the title compound as a potential long-range proton transfer (PT) switch has been studied by using the DFT and TD-DFT approaches. The data show that in aprotic solvents, the enol tautomer dominates, while the increase in the content of the keto tautomer (short-range PT) rises as a function of polarity of the solvent. In ethanol, due to specific solute–solvent stabilization through intermolecular hydrogen bonding, a substantial amount of the keto forms exists in solution. The irradiation leads to two competitive processes in the excited state, namely ESIPT and trans/cis isomerization around the azomethine bond as in other structurally similar Schiff bases. The studied compound is not suitable for bistable tautomeric switching, where long-range PT occurs, due to the difficult enolization of the coumarin carbonyl group.

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Solvent-induced E/Z(C=N)-isomerization of imines of some hydroxy-substituted formylcoumarins

Cited by 15 publications

References 11 publications

Design, synthesis, and biological activity of Schiff bases bearing salicyl and 7-hydroxycoumarinyl moieties

Design, synthesis, and biological activity of Schiff bases bearing salicyl and 7-hydroxycoumarinyl moieties

Remarkable and Unexpected Mechanism for (S)-3-Amino-4-(difluoromethylenyl)cyclohex-1-ene-1-carboxylic Acid as a Selective Inactivator of Human Ornithine Aminotransferase

Ground-State Tautomerism and Excited-State Proton Transfer in 7-Hydroxy-4-methyl-8-((phenylimino)methyl)-2H-chromen-2-one as a Potential Proton Crane

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