Understanding Chemistry and Unique NMR Characters of Novel Amide and Ester Leflunomide Analogues

Henen, Morkos A.; Hamdi, Abdelrahman; Farahat, Abdelbasset A.; Massoud, Mohammed A. M.

doi:10.3390/magnetochemistry3040041

Cited by 3 publications

(2 citation statements)

References 24 publications

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“…For both, there are two types of amide proton peaks, appearing at δ 11.3 and 8.3 ppm. Conjugation of the carbonyl amides to the triazole aromatic group results in downfield shifts of the amide protons. The differences between the 1 H chemical shifts of the two amides likely arises from intramolecular H‐bonding of the more downfield amide proton j at δ 11.3 ppm.…”

Section: Resultsmentioning

confidence: 99%

Internal plasticization of poly(vinyl) chloride using glutamic acid as a branched linker to incorporate four plasticizers per anchor point

Tek

Wojtecki

et al. 2019

J. Polym. Sci. Part A: Polym. Chem.

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Internal plasticization of polyvinyl chloride (PVC) using thermal azide‐alkyne Huisgen dipolar cycloaddition between azidized PVC and electron‐poor acetylenediamides incorporating a branched glutamic acid linker resulted in incorporation of four plasticizing moieties per attachment point on the polymer chain. A systematic study incorporating either alkyl or polyethylene glycol esters provided materials with varying degrees of plasticization, with depressed Tg values ranging from −1 °C to 62 °C. Three interesting trends were observed. First, Tg values of PVC bearing various internal plasticizers were shown to decrease with increasing chain length of the plasticizing ester. Second, branched internal plasticizers bearing triethylene glycol chains had lower Tg values compared to those with similar length long‐chain alkyl groups. Finally, thermogravimetric analysis of these internally plasticized PVC samples revealed that these branched internal plasticizers bearing alkyl chains are more thermally stable than similarity branched plasticizers bearing triethylene glycol units. These internal tetra‐plasticizers were synthesized and attached to PVC‐azide in three simple synthetic steps. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1821–1835

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Section: Resultsmentioning

confidence: 99%

Internal plasticization of poly(vinyl) chloride using glutamic acid as a branched linker to incorporate four plasticizers per anchor point

Tek

Wojtecki

et al. 2019

J. Polym. Sci. Part A: Polym. Chem.

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“…For asymmetric derivatives 5a-l, it was observed that the singlet proton peak of (4′-H) appeared in the range of (δ 5.43-5.55) for the compounds 5a and 5j-l, whereas the complete absence of this peak for the rest of the compounds, besides conspicuous jumping peak shift of (C-4′) to the range (143.5-144.9 ppm), indicating that oxidative aromatization into corresponding pyridine derivative was afforded. In addition, the singlet six protons peak of (2′-CH 3 , 6′-CH 3 ) appeared in the range (1.53-3.17 ppm) probably due to the conformational diamagnetic anisotropy with 3′,5′-groups, or 2-chloroquinoline (Henen et al, 2017). The IR spectrum showed typical absorption bands for ester C=O (1701-1720 cm −1 ) and ketone C=O was observed at around 1650 cm −1 .…”

Section: S C H E M E 1 Synthesis Of Symmetric Dhps 4a-hmentioning

confidence: 96%

In vitro cytotoxicity and docking study of novel symmetric and asymmetric dihydropyridines and pyridines as EGFR tyrosine kinase inhibitors

et al. 2022

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Quinolines have a weighty effect as anticancer agents and 1,4‐DHPs have demonstrated efficacy as anticancer agents in several studies, as well. New hybrid models of symmetric and asymmetric 1,4‐DHPs and pyridines linked at C3 of 2‐chloroquinoline as a new anticancer scaffold, were designed and synthesized. Hantszch 1,4‐DHPs method was adopted for chemical synthesis. MTT assay was performed for the evaluation of cytotoxicity, and EGFR tyrosine kinase assay was performed to investigate binding to our selected compounds, measured by ELISA. The IC50 expressed in µM values revealed that compounds 4a,b, and 5i,k showed the best results against the tested four cell lines than the reference drug 5‐Flurouuracil. Compound 5k displayed the most potent cytotoxic activity with IC50 values in the low µM range (12.03 ± 1.51: 20.09 ± 2.16 µM), compared with 5‐Fu IC50 range (40.74 ± 2.46: 63.81 ± 2.69 µM). The incorporation of 2‐chloroquinoline at C3 to C4 of 1,4‐DHP could be proposed as an anticancer scaffold rather than its analogous pyridines. Ester fragments connected to 1,4‐DHPs ring as a lipophilic part are essential for anticancer activity. The chirality at C4 improved the anticancer activity. The hydrogen and halogen bond facilitated protein‐ligand binding mode and affinity.

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Measuring the Magnetic Anisotropy of Metal–Metal Multiple Bonds: The Importance of Correcting for Ligand Effects

Lastowski,

Vogiatzis,

Girolami

2024

Inorg. Chem.

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We describe the synthesis and characterization of the quadruply-bonded dimer Mo2(CH2NMe2BH3)4 in which each molybdenum(II) center is bound to two chelating boranatodimethylaminomethyl (BDAM) ligands. The BDAM anions bind to the metal at one end by a metal–carbon σ bond and at the other by a three-center M–H–B interaction. Each BDAM ligand chelates to a single Mo atom so that the metal–metal bond is unbridged; the Mo–Mo distance is 2.114(2) Å. Structural and solution NMR data, analyzed via McConnell’s equation and supported by DFT calculations, show that the magnetic anisotropies associated with highly polarizable and π-bonding ligands (such as chloride groups and aryl rings) can greatly affect the NMR chemical shifts of reporter groups, so that ignoring their contributions leads to significant overestimates of the anisotropy due just to the metal–metal bond. We propose a method to quantify and correct for the magnetic anisotropy effects arising from the ligands. Application of this method to Mo2(BDAM)4 indicates that the magnetic anisotropy of the Mo–Mo quadruple bond in this molecule is about −800 × 10–36 m3 molecule–1. Anisotropies significantly higher than this value (as sometimes reported in the prior literature) are most likely incorrect.

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Understanding Chemistry and Unique NMR Characters of Novel Amide and Ester Leflunomide Analogues

Cited by 3 publications

References 24 publications

Internal plasticization of poly(vinyl) chloride using glutamic acid as a branched linker to incorporate four plasticizers per anchor point

Internal plasticization of poly(vinyl) chloride using glutamic acid as a branched linker to incorporate four plasticizers per anchor point

In vitro cytotoxicity and docking study of novel symmetric and asymmetric dihydropyridines and pyridines as EGFR tyrosine kinase inhibitors

Measuring the Magnetic Anisotropy of Metal–Metal Multiple Bonds: The Importance of Correcting for Ligand Effects

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