Synthesis and antispasmodic activity of nature identical substituted indanes and analogues

Discovery of anti-inflammatory agents from 3, 4-dihydronaphthalene-1(2H)-one derivatives by inhibiting NLRP3 inflammasome activation

NLRP3 inflammatory vesicles are a polymer of cellular innate immunity composed of a pair of proteins. The continuous activation of NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammatory vesicles induces the occurrence and enhancement of inflammatory response. In this study, a series of 3, 4-dihydronaphthalene-1(2H)-one derivatives (DHNs, 6a-u, 7a-e, 8a-n) were synthesized and characterized by NMR and HRMS. We evaluated the cytotoxicity and anti-inflammatory activity of all compounds in vitro, and selected 7a substituted by 7-Br in A-ring and 2-pyridylaldehyde in C-ring as effective lead compounds. Specifically, 7a can block the assembly and activation of NLRP3 inflammasome by down-regulating the expression of NLPR3 and apoptosis-associated speck-like protein containing a CARD (ASC), and inhibiting the production of reactive oxygen species (ROS) and other inflammatory mediators. In addition, 7a inhibits the phosphorylation of inhibitor kappa B alpha (IκBα) and NF-κB/p65 and the nuclear translocation of p65, thereby inhibiting nuclear factor kappa-B (NF-κB) signaling. Molecular docking analysis confirmed that 7a could reasonably bind the active sites of NLRP3, ASC and p65 proteins. Therefore, 7a is predicted as a potential NLRP3 inflammatory vesicle inhibitor and deserves further research and development.

Drug-Delivery Silver Nanoparticles: A New Perspective for Phenindione as an Anticoagulant

Anticoagulants prevent the blood from developing the coagulation process, which is the primary cause of death in thromboembolic illnesses. Phenindione (PID) is a well-known anticoagulant that is rarely employed because it totally prevents coagulation, which can be a life-threatening complication. The goal of the current study is to synthesize drug-loaded Ag NPs to slow down the coagulation process. Methods: A rapid synthesis and stabilization of silver nanoparticles as drug-delivery systems for phenindione (PID) were applied for the first time. Results: Several methods are used to determine the size of the resulting Ag NPs. Additionally, the drug-release capabilities of Ag NPs were established. Density functional theory (DFT) calculations were performed for the first time to indicate the nature of the interaction between PID and nanostructures. DFT findings supported that galactose-loaded nanostructure could be a proper delivery system for phenindione. The drug-loaded Ag NPs were characterized in vitro for their antimicrobial, cytotoxic, and anticoagulant activities, and ex vivo for spasmolytic activity. The obtained data confirmed the drug-release experiments. Drug-loaded Ag NPs showed that prothrombin time (PT, sec) and activated partial thromboplastin time (APTT, sec) are approximately 1.5 times longer than the normal values, while PID itself stopped coagulation at all. This can make the PID-loaded Ag NPs better therapeutic anticoagulants. PID was compared to PID-loaded Ag NPs in antimicrobial, spasmolytic activity, and cytotoxicity. All the experiments confirmed the drug-release results.

Bioactive indanes: insight into the bioactivity of indane dimers related to the lead anti-inflammatory molecule PH46A

Objectives

PH46A (1) demonstrates significant anti-inflammatory activity in phenotypic models but its mechanism and site of action have been elusive. Current study focused on the bioactivity of PH46 (2) and related novel indane dimers (6-10) to investigate the impact of changes in substitution and stereochemistry at the C-1 and C-2 positions of the PH46 (2) scaffold.

Methods

Cytotoxicity profiles of compounds were established using THP-1 macrophages and SW480 cells. Effects of the compounds were then evaluated at 10 µm using 5-lipoxygenase (LOX) and 15-LOX enzymes, and 5-LOX binding was evaluated in silico against NDGA, nitric oxide (NO) released from LPS-induced SW480 cells and cytokines in THP-1 macrophages (IL-6, IL-1β, TNF-α and IFN-γ) and in SW480 cells (IL-8).

Key findings

PH46 (2) and 7 cause reduction in NO, inhibition of 5-LOX with high binding energy and no cytotoxicity effects in THP-1 macrophages and SW480 cell lines (up to 50 µm). The cytokine profiling of the series demonstrated inhibition of IL-6 and TNF-α in THP-1 macrophages together with IL-8 in SW480 cells.

Conclusions

The observed profile of cytokine modulation (IL-6/ TNF-α, IL-8) and inhibition of release of NO and 5-LOX may contribute to the in vivo effects demonstrated by indane dimers and PH46A (1) in murine models of colitis.

Bioactive indanes: Development and validation of an LC-MS/MS bioanalytical method for the determination of PH46A, a new potential anti-inflammatory agent, in dog and rat plasma and its application to a pharmacokinetic study in dog

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Selective and sensitive determination by LC—MS/MS of PH46A, a new class of antiinflammation agent, in preclinical animal plasma.

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Full development and validation of the LC—MS/MS method in two preclinical species.

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A pharmacokinetic study of PH46A in dog using the method developed.

A new chemical entity, which is a chiral indane dimer, PH46A, has been developed by our research group. As a clinical candidate. PH46A has recently completed Phase I clinical studies in man. Previously, during its pre-clinical development, in in vivo pre-clinical studies PH46A showed potent anti-inflammatory properties, which can be targeted at a range of diseases, including inflammatory bowel disease (IBD). To support the pre-clinical development of this drug candidate, we developed a LC—MS/MS method for determining PH46 (the acid form of PH46A salt) in both dog and rat plasma using Compound 1 as internal standard (IS). Those species were selected for safety pharmacology and toxicology, as well as pharmacokinetics studies.

The method was validated over the range 10−10000 ng/mL for both matrices and the linearity, accuracy, precision and specificity over this range were demonstrated to be acceptable. No significant matrix effects or carryover were observed for both PH46 and IS and recovery was consistent. PH46 was found to be stable in both dog and rat plasma under the test conditions, such as at room temperature for >24 h, through 3 freeze/thaw cycles, and at -20 °C for >1 month. PH46 and IS in dog and rat plasma extracts were also found to be stable in the autosampler against fresh standard extracts on re-injection after 143.5 h and 243.5 h, respectively at 4 °C. 10- and 100-fold dilutions with control matrix were found not to affect the performance of the assay. This method was successfully applied to a pharmacokinetic study in the dog. With the exception of one dog, 003 M, oral administration of PH46A in gelatine capsules was well tolerated at a dose level of 100 mg/kg. The highest C_max was observed in animal 003 M. The rapid absorption and high plasma concentration observed for animal 003 M compared to the data for animals 001 M and 002 M may account for the sickness observed in this animal; however, the reasons for this have not been investigated.

Synthesis of Four Illudalane Sesquiterpenes Utilizing a One-Pot Diels-Alder/Oxidative Aromatization Sequence

The concise, divergent total syntheses of four illudalane sesquiterpenes using an indanone as the key intermediate are reported. The key elements in these total syntheses, which involve only four to six operational steps, consist of a Suzuki cross-coupling and a one-pot Diels-Alder/oxidative aromatization reaction.

Bioactive Indanes: Proof of Concept Study for Enantioselective Synthetic Routes to PH46A, a New Potential Anti-Inflammatory Agent

PH46A is a single enantiomer and a member of the 1,2-indane dimer family. It has two contiguous stereogenic centers with S,S configurations, one of which being a quaternary center, which has been developed as a clinical candidate for the treatment of inflammatory and autoimmune conditions. The current synthetic route to PH46A involves the generation of an unwanted enantiomer (R,R)-7, thus reducing the final yield significantly. Therefore, we have investigated potential alternatives to improve the efficiency of this synthesis. The first phase of the study has demonstrated proof of principle for a chiral alkylation of ketone 3 using phase-transfer catalysis, providing a key intermediate ketone (S)-4. The parent alkaloids required for the synthesis of PH46A, quinine or cinchonidine, have also been identified. Promising enantiomeric excesses of up to 50% have been achieved to date, and the use of an alternative substrate, unsaturated ketone 9, has also opened up further avenues for optimisation in future studies. The second part of the study involved preliminary screening the effects of a panel of hydrolase enzymes on (rac)-4 in order to identify a potential chemo-enzymatic route to optimise the introduction of chirality into PH46A at early stage of the synthesis. The hydrolase module has also yielded positive results; enzyme AH-46 with MtBE providing a selectivity factor of 8.4 with enantiomeric excess of 77%. Overall, positive results were obtained in this proof of concept study described herein. It is believed that conditions of both chiral PTC alkylation and biocatalytic hydrolysis could be optimised to further enhance the selectivity and improve the overall yield. This work is currently ongoing.

The indane diastereoisomers, PH2 and PH5: divergence between their effects in delayed-type hypersensitivity models and a model of colitis

OBJECTIVES

Compounds PH2 and PH5 are distereoisomers of novel indane compounds, synthesised as analogues of secondary metabolites of the fern, Onychium. In this study, we compare their effects on a variety of inflammatory models.

METHODS

In an effort to extend our knowledge of their anti-inflammatory profile, we have investigated their activity in two models of delayed-type hypersensitivity (DTH); the methylated bovine serum albumin model (mBSA) and the oxazolone contact hypersensitivity (CHS) model, on IL2 release from Jurkat cells and in the dextran sulphate sodium (DSS) murine model of inflammatory bowel disease.

KEY FINDINGS

Both diastereoisomers are equipotent in reducing paw swelling in the mBSA model and in inhibiting interleukin (IL) 2 release from Jurkat cells. They are equally ineffective in the oxazolone contact hypersensitivity model (CHS). Only the diastereoisomer, PH5, protects against DSS-induced colitis and of its two enantiomers, only the S,S-enantiomer, PH22, possesses this activity. PH2 is ineffective in the DSS model.

CONCLUSIONS

The results suggest that the beneficial effect of PH5, and its enantiomer PH22, in the DSS model is a consequence of an action on a target specific to the colitis model. The implications of such data suggest an unknown target in this disease model that may be exploited to therapeutic advantage.

Total Synthesis of Coprinol

The first synthesis of coprinol has been achieved from 2-methoxy-3,5-dimethylbenzaldehyde via the intermediacy of an indanone derivative where dialkylation, Friedel-Crafts acylation, demethylation, and regioselective formation of a primary -OH group from a chloroacetyl group are the key steps.

Molecular structure studies of (1S,2S)-2-benzyl-2,3-dihydro-2-(1H-inden-2-yl)-1H-inden-1-ol

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Chemical separation is used for racemate resolution.

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NMR analyses are used for single enantiomer structure education.

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Intermolecular interactions are observed by X-ray study.

The single enantiomer (1S,2S)-2-benzyl-2,3-dihydro-2-(1H-inden-2-yl)-1H-inden-1-ol (2), has recently been synthesized and isolated from its corresponding diastereoisomer (1). The molecular and crystal structures of this novel compound have been fully analyzed. The relative and absolute configurations have been determined by using a combination of analytical tools including X-ray crystallography, X-ray Powder Diffraction (XRPD) analysis and Nuclear Magnetic Resonance (NMR) spectroscopy.

2-(Di-phenyl-methyl-idene)-2,3-di-hydro-1H-inden-1-one

In the title mol-ecule, C22H16O, the indanone ring system is approximately planar with a dihedral angle between the fused rings of 5.13 (14)°. Two benzene rings are linked together at one side of a double bond, sitting on either side of the indanone ring system and making dihedral angles of 70.30 (12) and 44.74 (13)° with it. In the crystal, hydrogen bonding is not present, but weak C-H⋯π or π-π inter-actions occur and mol-ecules form a sheet-like structure in the bc plane.

(1S)-1-Phenylethanaminium 4-{[(1S,2S)-1-hydroxy-2,3-dihydro-1H,1'H-[2,2'-biinden]-2-yl]methyl}benzoate

The title molecular salt, C(8)H(12)N(+)·C(26)H(21)O(3)(-), contains a dimeric indane pharmacophore that demonstrates potent anti-inflammatory activity. The indane group of the anion exhibits some disorder about the α-C atom, which appears common to many structures containing this group. A model to account for the slight disorder was attempted, but this was deemed unsuccessful because applying bond-length constraints to all the bonds about the α-C atom led to instability in the refinement. The absolute configuration was determined crystallographically as S,S,S by anomalous dispersion methods with reference to both the Flack parameter and Bayesian statistics on Bijvoet differences. The configuration was also determined by an a priori knowledge of the absolute configuration of the (1S)-1-phenylethanaminium counter-ion. The molecules pack in the crystal structure to form an infinite two-dimensional hydrogen-bond network in the (100) plane of the unit cell.

6-(methylamino)hexane-1,2,3,4,5-pentanol 4-(((1S,2S)-1-hydroxy-2,3-dihydro-1H,1'H-[2,2-biinden]-2-yl)methyl)benzoate (PH46A): a novel small molecule with efficacy in murine models of colitis

The indane skeleton is found naturally and in several therapeutic molecules in medicinal chemistry. During our work on the anti-inflammatory activity of naturally occurring and synthetic indanes, we have synthesized a novel indane scaffold that has been optimized for both anti-inflammatory activity and bioavailability. We have evaluated our lead molecule, PH46A, in in vivo models of inflammatory bowel disease (IBD), an area of considerable unmet clinical need; current therapies are often unable to control the course of the disease. The compound significantly reduced histological damage and serum amyloid A (SAA) levels in IL-10(-/-) colitis mice, was efficacious in the 5% dextran sulfate sodium (DSS) colitis model, and compared favorably with prednisolone in this model and supports its potential use to treat acute exacerbations of the disease. Further, the graded response to the compound may also lend itself to be used at a lower dose to maintain periods of remission.

N-Cyclo-pentyl-N-(3-oxo-2,3-dihydro-1H-inden-1-yl)acetamide

The title mol-ecule, C(16)H(19)NO(2), consists of an indane moiety, which is connected through an N atom to an acetamide group and a cyclo-pentane ring. The N atom adopts planar triangular geometry. Inter-molecular inter-actions, such as π-π stacking or hydrogen bonding, were not observed.

A series of 1, 2-coupled indane dimers with mast cell stabilisation and smooth muscle relaxation properties

Asthma is characterised by bronchoconstriction and inflammation, with infiltration and activation of inflammatory cells such as eosinophils and mast cells, and subsequent release of inflammatory mediators. Much of the therapy directed at the treatment of asthma is either to provide symptomatic relief through bronchodilation or to reduce inflammation to prevent or delay airway remodelling. In an attempt to address both of these issues, a novel series of 1,2-indane dimers has been synthesized and evaluated for smooth muscle relaxant and mast cell stabilising activities. We have identified two lead compounds, 5 and 15, which have substantial mast cell stabilisation activity.

Illudalane sesquiterpenoids of the alcyopterosin series from the Antarctic marine soft coral Alcyonium grandis

Chemical investigation of the lipophilic extract of the Antarctic soft coral Alcyonium grandis led us to the finding of nine unreported sesquiterpenoids, 2-10. These molecules are members of the illudalane class and in particular belong to the group of alcyopterosins, illudalanes isolated from marine organisms. The structures of 2-10 were determined by interpretation of spectroscopic data. Repellency experiments conducted using the omnivorous Antarctic sea star Odontaster validus revealed a strong activity in the lipophilic extract of A. grandis against predation.

Design, synthesis, and biological evaluation of alcyopterosin A and illudalane derivatives as anticancer agents

The synthesis of alcyopterosin A and a series of new derivatives possessing an illudalane skeleton is described. The DNA binding properties of these compounds have been examined and compared to those of reference drugs using a UV spectroscopy technique. The antitumor activity of selected compounds against a panel of 60 human tumor cell lines was tested in the in vitro anticancer screening of the National Cancer Institute. Redox properties were also evaluated. Tested compounds showed significant DNA affinity, derivatives 6 and 15 exhibited remarkable antiproliferative activity and have been identified as new leads in the antitumor strategies.

Investigation into the mast cell stabilizing activity of nature-identical and synthetic indanones

As part of an ongoing search for novel molecules with therapeutic potential we examined the mediator release inhibition activity of a number of indanones and their derivatives. The aldol condensation product 18 was approximately twice as potent as disodium cromoglycate as an inhibitor of compound 48/80-stimulated histamine release from rat peritoneal mast cells. The activity of this class of dimeric indanone compound is significantly higher than controls and may represent a new class of mast cell stabilizing agents. Compound 18 has been selected for further biological evaluation of its mast cell stabilization profile.

Synthesis and antispasmodic activity of analogues of natural pterosins

The synthesis of an extensive range of analogues of natural pterosins using modified Heck coupling is reported. The smooth muscle relaxant activity of these compounds has been examimed. Several compounds with significant smooth muscle relaxant activity have been identified.

A Simple Synthetic Route to Pterosin F and Other Pterosins

A simple method for the preparation of pterosin F is described in which the key step involves a tandem reaction of Friedel–Crafts acylation–cycloalkylation between 2,6-dimethylphenethyl chloride and ethyl methacrylate