Discovery of 6-Acylamino/Sulfonamido Benzoxazolone with IL-6 Inhibitory Activity as Promising Therapeutic Agents for Ulcerative Colitis.

Ulcerative colitis has been widely concerned for its persistent upward trend, and the sustained overproduction of pro-inflammatory cytokines such as IL-6 remains a crucial factor in the development of UC. Therefore, the identification of new effective drugs to block inflammatory responses is an urgent and viable therapeutic strategy for UC. In our research, twenty-three 6-acylamino/sulfonamido benzoxazolone derivatives were synthesized, characterized, and evaluated for anti-inflammatory activity against NO and IL-6 production in LPS-induced RAW264.7 cells. The results demonstrated that most of the target compounds were capable of reducing the overexpression of NO and IL-6 to a certain degree. For the most active compounds 3i, 3j and 3 l, the inhibitory activities were superior or equivalent to those of the positive drug celecoxib with a dose-dependent relationship. Furthermore, animal experiments revealed that active derivatives 3i, 3j and 3 l exhibited definitive therapeutical effect on DSS induced ulcerative colitis in mice by mitigating weight loss and DAI score while decreasing levels of pro-inflammatory cytokines such as IL-6 and IFN-γ, simultaneously increasing production of anti-inflammatory cytokines IL-10. In addition, compounds 3i, 3j and 3 l could also inhibit the oxidative stress to alleviate ulcerative colitis by decreasing MDA and MPO levels. These finding demonstrated that compounds 3i, 3j and 3 l hold significant potential as novel therapeutic agents for ulcerative colitis.

Pyrosulfite-Involved Synthesis of Sulfides by Palladium-Catalyzed Decarboxylative Couplings.

The decarboxylative coupling using carboxylic acid and potassium metabisulfite, promoted by a palladium catalyst, is reported for the generation of sulfides. The coupling is performed using the easily available carboxylic acid and environmentally friendly inorganic sulfides as a divalent inorganic sulfur source. Not only aromatic acids but also aliphatic carboxylic acids are workable during the couplings. The method is applicable and practical to a scope of 20 examples and drug molecules.

New small-molecule alcohol synthesis by breaking the space limitation of the "aromatic cage" in Pseudomonas sp. AK1 BBOX.

Fe(II)/2OG-dependent oxygenase γ-butyrobetaine hydroxylase (BBOX) stereoselectively hydroxylates inactive C-H bonds and produces L-carnitine. It has potential applications in the biosynthesis of L-carnitine and the synthesis of other small molecule alcohols. In this paper, we systematically explore the substrate range of Pseudomonas sp. AK1 BBOX (psBBOX), with emphasis on the quaternary ammonium portion of γ-butyrobetaine (γ-BB). The space limitation of the "aromatic cage" in psBBOX in the hydroxylation of large quaternary ammonium analogues was studied, and the role of four aromatic amino acid residues in the substrate binding mode was analyzed. Consequently, the F188A mutant was developed with the ability to hydroxylate cyclic quaternary ammonium analogues and generate new alcohol compounds by breaking the limitation of the "aromatic cage".

Synthesis and Anti-Inflammatory Activity Evaluation of Benzoxazole Derivatives as New Myeloid Differentiation Protein 2 Inhibitors.

Myeloid differentiation protein 2 (MD2), a key TLR4 adaptor protein for sensing LPS, plays an important role in inflammatory process and has been identified as a promising target for the treatment of a variety of inflammatory diseases. In our study, a series of benzoxazolone derivatives were synthesized, characterized and tested for anti-inflammatory activity in vitro. The compounds 3c, 3d and 3g demonstrated the greatest anti-inflammatory activity against IL-6 with IC50 values of 10.14±0.08, 5.43±0.51 and 5.09±0.88 µM, respectively. Furthermore, the bis-ANS displacement assay revealed that these compounds competitively inhibited the binding between the probe bis-ANS and the MD2 protein. The most active compound 3g, revealed a directly bind with MD2 protein via Arg90 binding and a dissociation constant value of 1.52×10-6  mol L-1 as determined by the biological layer interference (BLI) assay. Our finding suggested that compounds 3g could be a promising lead compound as MD2 inhibitor for further anti-inflammatory agent development.

Asymmetric Synthesis of Spiropyrazolone-Fused Dihydrofuran-naphthoquinones Bearing Contiguous Stereocenters via a Michael Addition/Chlorination/Nucleophilic Substitution Sequence.

An enantioselective synthesis of spiropyrazolone-fused dihydrofuran-naphthoquinones is first demonstrated via a Michael addition/Chlorination/Nucleophilic substitution sequence. The reactions of 2-hydroxy-1,4-naphthoquinone and α,ß-unsaturated pyrazolones in the presence of the cinchona alkaloid derived hydrogen-bonding catalyst and NCS provide spiropyrazolone-fused 2,3-dihydronaphtho[2,3-b]furan-4,9-diones bearing contiguous stereocenters, of which one is the spiro quaternary stereocenter in high yields with exclusive diastereoselectivity and good to excellent enantioselectivities.

Diversity-Oriented Biosynthesis Yields l-Kynurenine Derivative-Based Neurological Drug Candidate Collection.

Natural product libraries with a remarkable range of biological activities play pivotal roles in drug discoveries due to their extraordinary structural complexity and immense diversity. l-Kynurenine (l-Kyn)-based derivatives are privileged pharmacophores that exhibit diverse therapeutic implications in neurological disorders. However, the difficulty in obtaining l-Kyn analogues with different skeletal structures has recently led to a decline in its medicinal research. Herein, we report a two-step, one-pot protocol for diversity-oriented biosynthesis of a collection of previously intractable l-Kyn-like compounds. The success of these challenging transformations mainly depends on unlocking the new catalytic scope of tryptophan 2,3-dioxygenases, followed by rational site-directed mutagenesis to modify the substrate domains further. As a result, 18 kynurenine analogues with diverse molecular scaffolds can be rapidly assembled in a predictable manner with 20-83% isolated yields, which not only fill the voids of the catalytic profile of tryptophan 2,3-dioxygenases with an array of substituent groups (e.g., F, Cl, Br, I, CH3, OCH3, and NO2) but also update the current understanding of its substrate spectrum. Our work highlights the great potential of existing enzymes in addressing long-standing synthetic challenges for facilitating the development or discovery of new drug candidates. Furthermore, our approach enables translating the reaction parameters from Eppendorf tubes to 1 L scale, affording l-4-Cl-Kyn and l-5-Cl-Kyn both on a gram scale with more than 80% isolated yields, and provides a promising alternative to further industrial applications.

Novel multi-component crystals of berberine with improved pharmaceutical properties.

As an extremely popular natural product, berberine (BER) is mainly used for gastroenteritis and diarrhoea caused by bacteria. Research has also revealed the potent and extensive pharmacological properties of BER including its anti-arrhythmic, anti-tumour, anti-inflammatory and hypoglycemic activities and so on; therefore, BER is a promising drug for further development. However, its commercial form with hydrochloride exhibits poor stability and solubility, which are detrimental to its clinical therapeutic effects. For these purposes, the salt form was regulated via the reactive crystallization of 8-hydroxy-7,8-dihydroberberine (8H-HBER) with five pharmaceutically suitable organic acids including malonic acid (MA), L-tartaric acid (LTA), D-tartaric acid (DTA), DL-tartaric acid (DLTA) and citric acid (CA), resulting in the six novel solid forms 1BER-1LTA-1W, 1BER-1DTA-1W, 1BER-1DLTA and 2BER-2CA as well as two rare multi-stoichiometric solid forms 1BER-1MA and 1BER-2MA-2W. The preparation of the multi-stoichiometric products was greatly influenced by both the crystallization solvent type and the molar ratio of reactants. The structures of these multi-component solid forms were determined using single-crystal X-ray diffraction and further characterized by powder X-ray diffraction, thermal analysis and Fourier transform infrared spectroscopy. Stability experiments showed that all samples prepared had superior physical stability under high temperature and high humidity. Furthermore, dissolution experiments demonstrated that the maximum apparent solubilities (MAS) of all the products were significantly improved compared with the commercial form of BER in dilute hydrochloric solution (pH = 1.2). In particular, the MAS of 1BER-1MA in dilute hydrochloric solution is as high as 34 times that of the commercial form. In addition, it is preliminarily confirmed that the MAS of the samples prepared in pure water and dilute hydrochloric solution is primarily influenced by a combination of factors including the packing index, intermolecular interactions, affinity of the counter-ion to the solvent, the molar ratio of the drug to counter-ion in the product and the common ion effect. These novel solids are potential candidates for BER solid forms with improved oral dosage design and may prompt further development.

Fluorescent dyes with multiple quaternary ammonium centers for specific image discrimination and Gram-positive antibacterial activity.

Three quaternary ammonium compounds (QACs), TPQA, T2PQA, and T3PQA, were synthesized and employed in antimicrobial tests against E. coli and S. aureus. It was confirmed that they exhibit selective bacteriostasis against S. aureus. The antibacterial activities of the compounds were evaluated via determining their minimum inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) against S. aureus using the 2,3,5-triphenyltetrazolium chloride (TTC) coloration method. Notably, T2PQA exhibited far better properties than TPQA and T3PQA, with the activity found to be dependent on the structure of the QA and the exposed hydrophobic groups. All three compounds showed promising potential for killing Gram-positive bacteria, efficiently guided by fluorescence imaging.

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.

Squaramide-catalysed asymmetric Friedel-Crafts alkylation of naphthol and unsaturated pyrazolones.

The first method for highly efficient asymmetric Michael-type Friedel-Crafts alkylation of naphthol and unsaturated pyrazolones has been accomplished under mild reaction conditions. In the presence of the chiral squaramide catalyst, a wide range of substrates are tolerated in excellent yields (up to 99%) with reasonable enantioselectivities (up to 96% ee).

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.

Diastereo- and Enantioselective Synthesis of Functionalized Cyclopentenes Containing a Quaternary Chiral Center via a Thiosquaramide-Catalyzed Cascade Michael-Henry Reaction.

An efficient method for the highly diastereoselective synthesis of chiral quaternary center-containing cyclopentenes via a cinchona alkaloid-derived thiosquaramide VIII-catalyzed tandem Michael-Henry reaction of phenacylmalononitriles and nitroolefins was deleveloped. Meanwhile, up to 98% of enantioselectivity was observed. A mechanism involving thiosqaramide-catalyzed asymmetric Michael addition and assisted E2 elimination was proposed based on experimental data and preliminary theoretical analysis (Hartree-Fock calculations).

Thiosquaramide-catalysed asymmetric double Michael addition of 2-(3H)-furanones to nitroolefines.

New chiral thiosquaramides and their applications in catalytic asymmetric double addition of 5-methyl-2(3H)-furanones to nitroolefins were described. Enantiomerically enriched 2,4,4-trisubstituted butenolides bearing a quaternary stereogenic center could be smoothly constructed with high diastereoselectivities (up to >99 : 1 dr) and excellent enantioselectivities (up to 95% ee) under mild conditions.

Highly enantioselective Michael addition of pyrazolin-5-ones to nitroolefins catalyzed by cinchona alkaloid derived 4-methylbenzoylthioureas.

Cinchona alkaloid-derived 4-methyl/nitro benzoylthioureas were synthesized, which smoothly catalyzed the asymmetric Michael addition of pyrazolin-5-ones to nitroolefins. The results showed that electronic effects of substituents in the benzene ring of benzoylthioureas have subtle influences on their catalytic abilities and electron donating methyl group is favored than electron withdrawing nitro group. Preliminary Hartree-Fock calculations revealed that in the catalytic cycle, hydrogen bond energies of the complex formed with 4-methylbenzoylthioureas are about 0.19 to 1.56 kcal/mol higher than with the corresponding 4-nitrobenzoylthioureas. 4-Methylbenzoylthioureas were identified as the most effective catalysts that promoted asymmetric Michael addition of pyrazolin-5-ones to nitroolefins to give the S- or R-products with high enantioselectivities.

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 and cytotoxic activities of novel 4-methoxy-substituted and 5-methyl-substituted (3'S,4'S)-(-)-cis-khellactone derivatives that induce apoptosis via the intrinsic pathway.

This study deals with the design and synthesis of a series of novel 4-methoxy-substituted and 5-methyl-substituted (3'S,4'S)-(-)-cis-khellactones. The newly synthesized compounds were characterized by 1H nuclear magnetic resonance (NMR), 13C-NMR, mass spectrometry, and elemental analysis. All the derivatives were subjected to in vitro cytotoxicity screening against HEPG-2 (human liver carcinoma), SGC-7901 (human gastric carcinoma), and LS174T (human colon carcinoma), by using the MTT assay. The results revealed that several of the 4-methoxy-substituted compounds exhibited potent cytotoxicity. Among these, compound 12e showed the highest activity against cancer cells which 50% inhibitory concentration (IC50) values were in the range of 6.1-9.2 µM with low toxicity on normal human hepatocyte. Preliminary investigation of possible mechanisms of action of compound 12e against HEPG-2 cells indicated possible induction of apoptosis, as determined by morphological observations and Annexin V/propidium iodide (PI) double staining, in addition to apparent dissipation of mitochondrial membrane potential (MMP), as measured by 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethyl-imidacarbocyanine iodide (JC-1) staining in combination with the activation of caspase-9 and caspase-3 by Western blot analysis. Overall, the data suggest that compound 12e may be a promising potential anti-cancer agent that could act primarily by inducing apoptosis through the mitochondria-mediated intrinsic pathway in human hepatoma cells.

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).

Apoptosis induced by farrerol in human gastric cancer SGC-7901 cells through the mitochondrial-mediated pathway.

Farrerol, a typical flavanone isolated from the Chinese medicinal plant Rhododendron dauricum L., has been found to show various biological activities. However, to the best of our knowledge, its inhibitory actions against cancer cells have not been reported as yet. Therefore, the present study aimed to investigate the cytotoxic and apoptotic effects of farrerol on human gastric cancer SGC-7901 cells. Farrerol showed a 50% inhibition of SGC-7901 cell growth at a concentration of 40.4 µmol/l for 24 h according to MTT assays. The cell morphology results indicated that SGC-7901 cells treated with farrerol showed several features of apoptotic cell death, which was also confirmed by the Annexin-V FITC/PI double-staining assay. Further studies showed that farrerol treatment induced the attenuation of mitochondrial membrane potential, accompanied by the release of Cyt-c and the activation of caspase-9 and caspase-3. Furthermore, farrerol decreased the gene expression of Bcl-2, whereas the gene expression level of Bax was found to increase after farrerol treatment. These combined results indicated that farrerol can induce apoptosis through a mitochondrial-mediated pathway.

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.