Construction of 2-alkynyl aza-spiro[4,5]indole scaffolds via sequential C-H activations for modular click chemistry libraries.

Herein, we have developed a strategy of sequential C-H activations of indole to construct novel 2-alkynyl aza-spiro[4,5]indole scaffolds, which incorporated both alkyne and spiro-units into indole. Gram-scale synthesis and a one-pot, three-step synthesis demonstrated the utility of this protocol. Hybrid conjugates with an oseltamivir derivative further offered a powerful tool for the construction of a versatile spiroindole-containing library via click chemistry.

4-Sulfonyloxy/alkoxy benzoxazolone derivatives with high anti-inflammatory activities: Synthesis, biological evaluation, and mechanims of action via p38/ERK-NF-κB/iNOS pathway.

In an effort to discover new agents with high anti-inflammatory activity, 22 new 4-sulfonyloxy/alkoxy benzoxazolone derivatives were synthesized, characterized, and evaluated for their anti-inflammatory activities against lipopolysaccharide (LPS)-induced nitric oxide (NO) production and TNF-α expression in RAW 264.7 cells in vitro. Most of these compounds displayed greater inhibitory ability against NO production than the lead compound 4-o-methyl-benzenesulfonyl benzoxazolone, and the most active compound 2h exhibited the strongest inhibitory activity against NO, IL-1ß, and IL-6 production with IC50 values 17.67, 20.07, and 8.61 µΜ, respectively. The effects of 2h were comparable or stronger than those of the positive control celecoxib. Compound 2h also displayed higher activity in vivo than celecoxib in a mouse model of xylene-induced ear edema, based on their inhibitory rates of 42.69% and 30.87%, respectively. Further molecular analysis revealed that compound 2h significantly reduced the iNOS levels in cell supernatant and suppressed the protein expression of iNOS, p-p38, p-ERK, and nuclear NF-κB. The results indicated that the anti-inflammatory effect of 2h might be realized through the regulation of ERK- and p38-mediated mitogen-activated protein kinase (MAPK)-NF-κB/iNOS signaling, thereby reducing the excessive release of NO, IL-1ß, and IL-6. Our findings demonstrated that compound 2h, a new benzoxazolone derivative, could inhibit activation of the MAPK-NF-κB/iNOS pathway, supporting its potential as a novel anti-inflammatory agent.

Design and synthesis of new disubstituted benzoxazolone derivatives that act as iNOS inhibitors with potent anti-inflammatory activity against LPS-induced acute lung injury (ALI).

Acute lung injury (ALI) is a pulmonary disease that acts as a severe acute inflammatory response with no specific drugs. iNOS, a catalyst of the excessive production of NO, has been demonstrated to participate in the inflammatory process, and targeting iNOS may be a promising therapeutic pathway to alleviate ALI. In our research, eighteen new disubstituted benzoxazolone derivatives were synthesized, characterized, and evaluated for activity against NO production in an LPS-induced RAW264.7 cell. The results showed that these compounds could obviously inhibit the over-generation of NO and disubstitution at the 4, N-position of the benzoxazolone ring, presenting better potency than substitution only at the 4-position. Among the analogues generated, compounds 2c, 2d, and 3d showed NO inhibitory activity with IC50 values of 16.43, 14.72, and 13.44 µM and iNOS inhibitory activity with IC50 values of 4.605, 3.342, and 9.733 µM, respectively. Meanwhile, compounds 2c, 2d, and 3d could also inhibit the release of IL-6, IL-1ß in vitro and suppress xylene-induced ear edema in vivo to realize anti-inflammatory activity. Furthermore, compound 2d could significantly protect the LPS-induced ALI, presenting as decreased inflammatory cytokines and obvious pathological changes. Immunohistochemistry and molecular modeling demonstrated that compound 2d significantly inhibited the expression of iNOS in vivo and interacted with iNOS through two hydrogen bindings with the MET368 and ILE195 residues of the iNOS protein. These results demonstrated that compound 2d could be a promising lead structure for iNOS inhibitors, with anti-inflammatory activity to treat LPS-induced acute lung injury.

Anti-inflammatory effects of 4-o-methyl-benzenesulfonyl benzoxazolone (MBB) in vivo and in vitro as a novel NSAIDs lead compound.

BACKGROUND: Great attention has been paid to the development of novel anti-inflammatory drugs to overcome the adverse reactions of traditional drugs. Recently, a new compound 4-o-methyl-benzenesulfonyl benzoxazolone (MBB) we have prepared attracted our attention for its promising anti-inflammatory activity and low toxicity. The present study aimed to further investigate the anti-inflammatory effects of MBB both in vivo and in vitro in order to determine its potential as a novel NSAIDs lead compound. METHODS: The anti-inflammatory effects in vivo were evaluated using acetic acid-induced mice writhing, xylene-induced mice ear edema and collagen-induced rat arthritis. NO, TNF-α, IL-6, IL-1ß and iNOS productions by LPS-stimulated RAW264.7 cells were determined to investigate the basis of anti-inflammatory effects. Finally, the COX inhibition effect was tested in vitro using COX inhibitor screening assay kit. RESULTS: MBB could significantly decrease the writhing and ear swelling in a dose-dependent manner, and it also had a moderate anti-arthritic potential associated with an attenuation of arthritis index score, arthritis swelling, and inhibition of TNF-α and IL-1ß. MBB could inhibit the activity of NO, TNF-α, IL-6, IL-1ß and iNOS to perform its activity in vitro, but it had no effect against COX-1 and COX-2. The anti-inflammation effect may be mediated via the inhibition of iNOS to reduce the production of inflammatory mediators which should be further confirmed. CONCLUSIONS: The compound MBB displayed anti-inflammatory and anti-arthritic effect, and it could be considered as a new NSAIDs lead compound for the further structure modification to develop novel anti-inflammatory drugs.

Synthesis of Novel Nitrogen-Containing Heterocycle Bromophenols and Their Interaction with Keap1 Protein by Molecular Docking.

We previously reported 5,2'-dibromo-2,4',5'-trihydroxydiphenylmethanoe (LM49), a bromophenol analogue that shows strong protection from oxidative stress injury owing to its superior anti-inflammatory, antioxidant, and anti-apoptotic properties. A series of novel nitrogen-containing heterocycle bromophenols were herein synthesized by introducing substituted piperidine, piperazine, and imidazole to modify 2-position of the lead compound LM49. By further evaluating their cytoprotective activity against H2O2 induced injury in EA.hy926 cells, 14 target bromophenols showed moderate-to-potent activity with EC50 values in the range of 0.9-6.3 µM, which were stronger than that of quercetin (EC50: 18.0 µM), a positive reference compound. Of these, the most potent compound 22b is a piperazine bromophenol with an EC50 value of 0.9 µM equivalent to the LM49. Molecular docking studies were subsequently performed to deduce the affinity and binding mode of derived halophenols toward the Keap1 Kelch domain, the docking results exhibited that the small molecule 22b is well accommodated by the bound region of Keap1-Kelch and Nrf2 through stable hydrogen bonds and hydrophobic interaction, which contributed to the enhancement of affinity and stability between the ligand and receptor. The above facts suggest that 22b is a promising pharmacological candidate for further cardiovascular drug development. Moreover, the targeting Keap1-Nrf2 protein-protein interaction may be an emerging strategy for halophenols to selectively and effectively activate Nrf2 triggering downstream protective genes defending against injury.

Highly enantioselective Michael addition of cyclohexanone to nitroolefins catalyzed by pyrrolidine-based bifunctional benzoylthiourea in water.

Organocatalysis and aqueous reactions are identified as the focus of the greening of chemistry. Combining these two strategies effectively remains an interesting challenge in organic synthesis. Herein, we used pyrrolidine-based benzoylthiourea 1c to catalyze the asymmetric Michael addition of cyclohexanone to various nitroolefins in water to afford the corresponding compounds in moderate to good yields, and with excellent diastereoselectivities (up to >99:1 dr) and enantioselectivities (up to 99% ee).

Switching the Z/E selectivity in the palladium(II)-catalyzed decarboxylative Heck arylations of trans-cinnamaldehydes by solvent.

The Z/E selectivity of Pd(II)-catalyzed decarboxylative Heck-type arylations of trans-cinnamaldehydes can be controlled readily by switching the reaction solvent. Depending on the type of solvent used, each of the two isomeric products can be obtained with good to excellent Z/E ratio. In THF, Z-isomers were formed preferentially, whereas DMF provided the E-isomers predominantly.

A chiral benzoylthiourea-pyrrolidine catalyst for the highly enantioselective Michael addition of ketones to chalcones.

A benzoylthiourea-pyrrolidine catalyst was developed for the asymmetric Michael addition of ketones to chalcones. The corresponding products were obtained in high yields with high level of diastereoselectivities (up to 99:1 dr) and high level of enantioselectivities (up to 94% ee) under mild conditions.

Diorganotin(IV) derivatives of substituted N-hydroxybenzamides with selective cytotoxicity in vitro and potent antitumor activity in vivo.

Four diorganotin(IV) derivatives, dibutylbis[4-chloro-N-(hydroxy-<κ>O)benzamidato-<κ>O]tin(IV) (DBDCT), dibutylbis[2,6-difluoro-N-(hydroxy-<κ>O)benzamidato-<κ>O]tin(IV) (DBDFT), bis[2,4-difluoro-N-(hydroxy-<κ>O)benzamidato-<κ>O]diphenyltin(IV) (DPDFT), and bis[2,4-dichloro-N-(hydroxy-<κ>O)benzamidato-<κ>O]diphenyltin(IV) (DPDCT), were compared for their antitumor activity in vitro and in vivo along with their cytotoxic selectivity against human normal cells and cancer cells. The in vitro cytotoxic activities against seven human cancer cell lines including Hep G2, SHSY5Y, HEC-1-B, EC, T24, HeLa and A549 along with human liver HL-7702, a human normal hepatocytes cell, were observed by the MTT assay. The cytotoxic selectivity of the four compounds was compared by using HL-7702 and Hep G2. The in vivo antitumor tests towards the sarcoma carcinoma S180 and hepatocellular carcinoma H22 on mice were carried out via injection intraperitoneally with cisplatin as the positive contrast drug. The results showed that, among the four compounds, DBDCT displayed the strongest cytotoxicity against the seven cancer cell lines. DPDCT had the highest antitumor activity in vivo. However, both of them had no cytotoxic selectivity against the human hepatocellular carcinoma HepG2 cells and normal liver HL-7702 cells. DPDFT had the most significant cytotoxic selectivity against HepG2 and displayed significantly antitumor activity in vitro and in vivo. In conclusion, DPDFT could act as a promising lead compound for the further structure optimization owing to its relatively low toxicity to human normal cell and potent antitumor activity against cancer cells.

Synthesis and biological activity of 4-substituted benzoxazolone derivatives as a new class of sEH inhibitors with high anti-inflammatory activity in vivo.

A series of novel 4-substituted benzoxazolone derivatives was synthesized, characterized and evaluated as human soluble epoxide hydrolase (sEH) inhibitors and anti-inflammatory agents. Some compounds showed moderate sEH inhibitory activities in vitro, and two novel compounds, 3g and 4j, exhibited the highest activities with IC50 values of 1.72 and 1.07 µM, respectively. Structure-activity relationships (SARs) revealed that introduction of a lipophilic amino acid resulted in an obvious increase in the sEH inhibitory activity, especially for derivatives containing a phenyl (3d, IC(50) = 2.67 µM), pyrrolidine (3g, IC(50) = 1.72 µM), or sulfhydryl group (3e, IC(50)=3.02 µM). Several compounds (3a-3g) were tested in vivo using a xylene-induced ear edema mouse model. Three compounds (3d, 3f, and 3g) showed strong anti-inflammatory activities in vivo which were higher than that of Chlorzoxazone, a reference drug widely used in the clinic. Our investigation provided a novel type of sEH inhibitor and anti-inflammatory agent that may lead to the discovery of a potential candidate for clinical use.

Structure-activity relationship of halophenols as a new class of protein tyrosine kinase inhibitors.

A series of new benzophenone and diphenylmethane halophenol derivatives were prepared. Their structures were established based on (1)H NMR, (13)C NMR and HRMS data. All prepared compounds were screened for their in vitro protein tyrosine kinase (PTK) inhibitory activities. The effects of modification of the linker, functional groups and substituted positions at the phenyl ring on PTK inhibitory activity were investigated. Twelve halophenols showed significant PTK inhibitory activity. Among them, compounds 6c, 6d, 7d, 9d, 10d, 11d and 13d exhibited stronger activities than that of genistein, the positive reference compound. The results gave a relatively full and definite description of the structure-activity relationship and provided a foundation for further design and structure optimization of the halophenols.

Synthesis and in vitro protein tyrosine kinase inhibitory activity of furan-2-yl(phenyl)methanone derivatives.

A series of novel furan-2-yl(phenyl)methanone derivatives were synthesized, and their structures were established on the basis of ¹H-NMR, ¹³C-NMR and mass spectral data. All the prepared compounds were screened for their in vitro protein tyrosine kinase inhibitory activity and several new derivatives exhibited promising activity, which, in some cases, was identical to, or even better than that of genistein, a positive reference compound. The preliminary structure-activity relationships of these compounds were investigated and are discussed.