•Synthesis of 1,2,3,4–tetrahydroquinolines 9 & 11 was achieved in good yields.•All the synthesized compounds were characterized by NMR, Mass & IR Spectroscopy.•Compounds 9 & 11 cored with electronic ...push-pull system and showed blue fluorescence.•Push-pull electronic system in compounds 9 & 11 lead Internal Charge Transfer.•The stoke shifts, quantum yield and band gap were calculated for compounds 9 & 11.
A metal-free, ultrasound-assisted, fast synthesis of fluorescent N-Boc-protected 1,2,3,4–tetrahydroquinolines 9a-p is described through carbanion-induced ring transformation of 6-aryl-2H-pyran-2-ones 7 with tert‑butyl 3-oxopiperidine-1-carboxylate 8 under basic condition. The reaction products 9a-p were isolated in high yields. Our synthetic approach is flexible for introducing electron-withdrawing and electron-donating groups. All the synthesized 1,2,3,4–tetrahydroquinolines 9a-p showed blue fluorescence in the range of 422–470 nm. Based on the optical behavior of compounds 9a–p, we calculated stokes shift, quantum yield and optical band gap which are highly influenced by the substituents in the ring.
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We have previously reported the isolation of four compounds, caffeoyloxy-5,6-dihydro-4-methyl-(2H)-pyran-2-one (CDMP), olinioside, caffeic acid and 3-hydroxylup-12-en-28-oic acid, from the leaves of ...Olinia usambarensis. Here, we evaluated the inhibitory effects of these compounds on lipopolysaccharide (LPS)-induced production of nitric oxide (NO) and prostaglandin E2 (PGE2) in RAW 264.7 macrophages, and found that CDMP is the most potent of these two pro-inflammatory mediators (IC50; 12.12 μM and 10.78 μM, respectively). Consistent with these results, CDMP also down-regulated inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), and interleukin 6 (IL-6) at the protein and mRNA levels in LPS-treated RAW 264.7 macrophages. Furthermore, CDMP suppressed LPS-induced nuclear factor κB (NF-κB) activation by decreasing p65 nuclear translocation through the phosphorylation and degradation of the inhibitory κBα (IκBα). CDMP also attenuated LPS-induced transcriptional and DNA-binding activities of activator protein 1 (AP-1) by suppressing the phosphorylation and expression of c-Fos and c-Jun. Finally, CDMP considerably suppressed the LPS-induced phosphorylation of c-Jun N-terminal kinase (JNK), but did not affect the phosphorylation of p38 or extracellular signal-regulated kinase (ERK). Taken together, our data suggest that CDMP down-regulates genes encoding pro-inflammatory mediators and cytokines, such as iNOS, COX-2, TNF-α, IL-1β, and IL-6 via NF-κB and JNK/AP-1 inactivation in LPS-induced RAW 264.7 macrophages.
•CDMP from Olinia usambarensis leaves suppressed LPS-induced pro-inflammatory mediators.•CDMP inhibited LPS-induced NF-κB activation by blocking IκBα degradation.•CDMP inhibited LPS-induced phosphorylation and nuclear expression of c-Fos and c-Jun.•CDMP decreased LPS-induced JNK phosphorylation, but not p38 and JNK.•CDMP is one of the active anti-inflammatory components of O. usambarensis leaves.
An ultrasound-assisted rapid synthesis of meta-terphenyls 9 by the carbanion-induced ring transformation reaction of 6-aryl-5-methyl-2H-pyran-2-ones 7 with functionalized ketones 8 under basic ...conditions at room temperature has been delineated. The present method gives an easy access to functionally crowded m-terphenyls 9 with notable features including mild reaction condition, remarkable functional groups tolerance, shorter reaction time and high product yields.
A new 2
H
-pyran-2-one derivative, 4-hydroxy-6-(3-methoxyphenethyl)-2
H
-pyran-2-one (
1
), has been isolated from the rhizomes of
Alpinia pricei
var.
pricei
, together with six known compounds, ...dihydro-5,6-dehydrokawain (
2
), 5,6-dehydrokawain (
3
), 1,7-bis(4-hydroxyphenyl)-1,4,6-heptatrien-3-one (
4
), bisdemethoxycurcumin (
5
), apigenin (
6
), and kaempferol (
7
). The structure of new compound
1
was determined through spectroscopic and MS analyses. Among the isolates, 1,7-bis(4-hydroxyphenyl)-1,4,6-heptatrien-3-one (
4
), bisdemethoxycurcumin (
5
), apigenin (
6
), and kaempferol (
7
) showed potent inhibition with IC
50
values of 25.47 ± 2.04, 22.39 ± 1.83, 14.60 ± 0.87, and 18.44 ± 1.50 μM, respectively, against LPS-induced NO generation.
A metal‐free approach for the synthesis of p‐terphenyls 7 a–i and cyclic p‐terphenyls 9 a–d and 11 a–d is described via carbanion induced ring transformation reaction of 6‐biphenyl‐2H‐pyran‐2‐ones 5 ...with malononitrile 6, cyclohexanone 8 and 1,4‐cyclohexanedione monoethylene ketal 10 respectively. Additionally, the base‐mediated ring transformation reactions were working smoothly under mild reaction conditions and ring transformation products 7, 9 and 11 were isolated in good to excellent yields. The synthetic approach provides the flexibility of introducing of both electron‐withdrawing and ‐donating functionalities in p‐terphenyl architecture. Moreover, the photo physical properties of compounds 7, 9 and 11 were analyzed using UV‐visible and Fluorescence Spectroscopy. p‐Terphenyls 7 c showed cyan fluorescence in chloroform (λmax (em): 508 nm) and acetonitrile (λmax (em): 420 nm) while cyclic p‐terphenyl 9 a showed blue fluorescence in chloroform and 1,4‐dioxane (λmax (em): 470 nm). Similarly, compound 11 a showed blue fluorescence in chloroform (λmax (em): 468 nm) and 1,4‐dioxane (λmax (em): 473 nm). Additionally, the thermal stability of synthesized cyclic p‐terphenyls 11 a, 11 c and 11 d were also studied using TG and DTA techniques.
A simple and convenient route for the synthesis of cyclic and acyclic para‐terphenyls was described through carbanion‐induced ring transformation of 2H‐pyran‐2‐ones under mild reaction conditions. The potential of the method lies in generating p‐terphenyls functionalized with different electron donating and withdrawing functionalities in terphenyls architecture. Moreover, the photo‐physical behaviour of synthesized p‐terphenyls was studied using UV‐visible and Fluorescence Spectroscopy. Additionally, the thermal stability of cyclic p‐terphenyls was also studied using TG and DTA techniques.
A modified version of the three-component Biginelli reaction of 4-hydroxy-6-methyl-2
H
-pyran-2-one with aromatic aldehydes and 1
H
-benzimidazol-2-amine has been studied under thermal and microwave ...activation. Depending on the substituent in the initial aldehyde, angularly fused 5,6-dihydro-4
H
-benzo4,5imidazo1,2-
a
pyranopyrimidin-4-ones or 2-amino-1
H
-benzimidazol-3-ium arylbis(4-hydroxy-6-methyl-2-oxo-2
H
-pyran-3-yl)methanides have been obtained. A plausible mechanism of their formation has been proposed.
First ever synthesis of functionalized 5,7-dihydro-6H-dibenzod,f1,3diazepin-6-ones (6, 9) has been developed through base induced ring transformation of 2H-pyran-2-one-3-carbonitriles with ...indolin-2-ones. A protocol for alkenylating indolin-2-ones by 2H-pyran-2-one-3-carbonitriles has also been developed to obtain 3-alkenylindolin-2-ones (11). The nature and behaviour of intermolecular interactions of these compounds are studied by single crystal-X-ray analysis and quantum chemical calculations.
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The unprecedented reaction of ketone‐containing aromatic pyridinium salts 3a‐e and alkynyl Fischer complexes 1a‐f proceeds via a mild domino process to provide 4,6‐disubstituted pyran‐2‐ones 5a‐k and ...2,3,5‐trisubstituted furans 6a‐h (45‐97%). According of the results of isotopic labeling experiments, a mechanism involving an initial Michael addition appears to be the key step, obtaining a mesomeric structure responsible for the formation of both products.
An unexpected reactivity of alkynyl Fischer carbenes and pyridinium salts were found.
A plausible mechanism for the formation of the oxo‐heterocycles involves a domino process.
Through this method, pyran‐2‐ones are obtained in a selective fashion.
A new chromone and a new aliphatic ester were isolated from the EtOAc extract of myceliums of Daldinia eschscholtzii. Their structures were elucidated as (R)-5-hydroxy-8-methoxy-2-methylchroman-4-one ...(1) and (E)-6-(non-3-en-1-yl) -2H-pyran-2-one (2) by interpretation of the spectroscopic evidence.
