Synthesis of 1,2,4‐Triazolo[4,3‐<i>a</i>]pyridines and Related Heterocycles by Sequential Condensation and Iodine‐Mediated Oxidative Cyclization

Li, Ertong; Hu, Zhiyuan; Song, Lina; Yu, Wenquan; Chang, Junbiao

doi:10.1002/chem.201601744

Cited by 33 publications

(6 citation statements)

References 31 publications

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“…4 Several examples of iodine-mediated oxidative cyclization have been reported with stoichiometric amounts of molecular iodine as an oxidant. 5 A microwave irradiation strategy involving the anion-mediated synthesis of 3-amino-[1,2,4]-triazolo [4,3-a]pyridines from thiosemicarbazides is subsequently disclosed. 6 This approach is free of oxidants but with narrow substrate scopes, low yields, and high temperature.…”

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confidence: 99%

Access to 3-Amino-[1,2,4]-triazolo Pyridines and Related Heterocycles via Electrochemically Induced Desulfurative Cyclization

Chen

Zou

et al. 2022

Org. Lett.

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An efficient, one-pot approach has been established for synthesizing a wide range of 3-amino-[1,2,4]-triazolo pyridines and related heterocycles from the electrochemically induced desulfurative cyclization of 2-hydrazinopyridines with isothiocyanates. The protocol allows for the formation of C−N bonds under simple conditions without transition metals or external oxidants. The practicability of this strategy is demonstrated by its broad substrate scope, good functional group compatibility, and gramscale synthesis. The late-stage modification of 3-amino-[1,2,4]triazolo pyridines enables us to obtain several molecules with potent anticancer activity.

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confidence: 99%

Access to 3-Amino-[1,2,4]-triazolo Pyridines and Related Heterocycles via Electrochemically Induced Desulfurative Cyclization

Chen

Zou

et al. 2022

Org. Lett.

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“…Condensation reaction of compound 4 and 6 a‐d with 2 ‐hydrazinopyridine afforded corresponding pyridylhydrazones 7 a‐e . Target compounds 8 a‐e were finally synthesized by the oxidative cyclisation of respective phenothiazine pyridylhydrazones 7 a ‐ e as depicted in Scheme . Various reagents like chloramine‐T, NBS/DBU and I 2 /K 2 CO 3 were scrutinized for this transformation.…”

Section: Resultsmentioning

confidence: 99%

“…Target compounds 8 a‐e were finally synthesized by the oxidative cyclisation of respective phenothiazine pyridylhydrazones 7 a ‐ e as depicted in Scheme . Various reagents like chloramine‐T, NBS/DBU and I 2 /K 2 CO 3 were scrutinized for this transformation. Very low yields were obtained with chloramine‐T for the oxidative cyclisation while several impurities or by products were observed with NBS/DBU.…”

Section: Resultsmentioning

confidence: 99%

Design, Synthesis and Characterisation of Novel Phenothiazine‐Based Triazolopyridine Derivatives: Evaluation of Anti‐Breast Cancer Activity on Human Breast Carcinoma

Sachdeva

Low

et al. 2019

ChemistrySelect

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A series of novel phenothiazine based [1,2,4]triazolo[4, 3‐a]pyridine scaffolds were designed and synthesized in good yields by the oxidative cyclisation of phenothiazine pyridylhydrazones. Biological responses of all compounds toward a panel of human breast cancer cells (MDA‐MB‐231, MDA‐MB‐468, MCF7, SKBR3 and T47D) and human non‐tumorigenic epithelial breast cells (MCF10 A) were evaluated. Structure‐activity relationship revealed that compound with pendant phenyl ring on phenothiazine exhibited significant cytotoxic activity and apoptotic induction effects against breast cancer cell line with IC50 value 10.2 to 17.6 μM. Notably, the cytotoxic effect was 3.5 fold higher on cancer than non‐cancer cells, indicating potential control of breast cancer with lower side effects. Molecular docking studies confirmed the presence of hydrophobic contacts between appended phenyl ring, triazolopyridine and phenothiazine moieties with adjacent residues within the binding pocket of tubulin. One of the nitrogen in the triazolo ring also showed hydrogen bonding with tubulin. These tubulin interactions were also found with the taxane ring of paclitaxel. Cell cycle analysis confirmed the G2/M arrest induced by this compound on human breast cancer cells. Therefore, the potential anti‐cancer, pro‐apoptotic, and cell cycle arrest warrant further development of this molecule as a new class of anticancer agent.

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“…Fused 1,2,4-triazolo [4,3-a]pyridines are an important class of compounds of therapeutic interest. [1][2][3][4][5][6] Two examples of 1,2,4triazolo [4,3-a]pyridine derivatives reported as P-38α inhibitor [7] and antibacterial compound [8] are shown in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Molecular Modelling and In Vitro Anti‐inflammatory Activity of Novel 1,2,4‐Triazolo[4,3‐a]quinoxaline Derivatives

et al. 2022

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In this study, a series of 12 new 1,2,4‐triazolo[4,3‐a]quinoxalines (3 a‐l) were synthesized to investigate their anti‐inflammatory activities. An efficient method for synthesis of 1,2,4‐triazolo[4,3‐a]quinoxaline compounds (3 a‐l) rendered a cyclo‐condensation between iminoester derivatives (Compounds 1 a‐l) and 1‐(quinoxalin‐2‐yl)hydrazine (Compound 2). The synthesized compound's structural elucidation was carried out using 1H‐ and 13C‐NMR, Mass analysis. Cytotoxicity profiles of the title compounds were assessed by MTT assay, and anti‐inflammatory activities were investigated by determining nitrite levels in LPS‐induced RAW264.7 murine macrophage cells. In addition, the ability of the compounds to reduce nitrite levels was modelled using molecular docking method. Compound 3 a‐l showed good anti‐inflammatory activities. Compound 3 f exhibited the most remarkable nitrite‐reducing effect (65.12±1.62 %), which was similar to the nitrite inhibition seen with IND (63.83±4.20 %) compared to LPS‐induced control. Besides, 3 f was followed by 3 i and 3 g, causing a significant decline in nitrite levels (51.56±8.68 % and 51.13±8.29 %, respectively). Molecular docking studies predicted that the compounds showed high affinity and formed key interactions with the active site of inducible nitric oxide synthase (iNOS), a key enzyme responsible for elevated nitrite levels. Thus, the current study explored a new series of 1,2,4‐triazolo[4,3‐a]quinoxaline analogs with promising nitrite‐reducing effects, most probably due to iNOS inhibition.

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Synthesis of 1,2,4‐Triazolo[4,3‐a]pyridines and Related Heterocycles by Sequential Condensation and Iodine‐Mediated Oxidative Cyclization

Cited by 33 publications

References 31 publications

Access to 3-Amino-[1,2,4]-triazolo Pyridines and Related Heterocycles via Electrochemically Induced Desulfurative Cyclization

Access to 3-Amino-[1,2,4]-triazolo Pyridines and Related Heterocycles via Electrochemically Induced Desulfurative Cyclization

Design, Synthesis and Characterisation of Novel Phenothiazine‐Based Triazolopyridine Derivatives: Evaluation of Anti‐Breast Cancer Activity on Human Breast Carcinoma

Synthesis, Molecular Modelling and In Vitro Anti‐inflammatory Activity of Novel 1,2,4‐Triazolo[4,3‐a]quinoxaline Derivatives

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