Sodium [2'-[(cyclopropanecarbonyl-ethyl-amino)-methyl]-4'-(6-ethoxy-pyridin-3-yl)-6-methoxy-biphenyl-3-yl]-acetate (AM432): a potent, selective prostaglandin D2 receptor antagonist

Compound 21 (AM432) was identified as a potent and selective antagonist of the DP₂ receptor (CRTH2). Modification of a bi-aryl core identified a series of tri-aryl antagonists of which compound 21 proved a viable clinical candidate. AM432 shows excellent potency in a human whole blood eosinophil shape change assay with prolonged incubation, a comparatively long off-rate from the DP₂ receptor, excellent pharmacokinetics in dog and in vivo activity in two mouse models of inflammatory disease after oral dosing.     

Novel pyrrolidine melanin-concentrating hormone receptor 1 antagonists with reduced hERG inhibition

We discovered novel pyrrolidine MCHR1 antagonist 1 possessing moderate potency. Profiling of pyrrolidine 1 demonstrated that it was an inhibitor of the hERG channel. Investigation of the structure-activity relationship of this class of pyrrolidines allowed us to optimize the MCHR1 potency and decrease the hERG inhibition. Increasing the acidity of the amide proton by converting the benzamide in lead 1 to an anilide provided single digit nanomolar MCHR1 antagonists while replacing the dimethoxyphenyl ring of 1 with alkyl groups possessing increased polarity dramatically reduced the hERG inhibition.     

Selective antagonists of mouse trace amine-associated receptor 1 (mTAAR1): discovery of EPPTB (RO5212773)

High throughput screening of the Roche compound library identified benzanilides such as 1 and 2 as antagonists of TAAR1. Optimisation of this hit series led to the first selective TAAR1 antagonist (N-(3-Ethoxy-phenyl)-4-pyrrolidin-1-yl-3-trifluoromethyl-benzamide EPPTB (RO5212773, 9f) having IC₅₀ of 28 nM at mouse TAAR1.     

Discovery of 3-aryl-5-acylpiperazinyl-pyrazoles as antagonists to the NK3 receptor

A series of 3-aryl-5-acylpiperazinyl-pyrazoles (e.g., 3a-b) initially identified through a high-throughput screening campaign using the aequorin Ca²⁺ bioluminescence assay as novel, potent small molecule antagonists of the G protein-coupled human tachykinin NK₃ receptor (hNK3-R) is described. Preliminary profiling revealed poor plasma and metabolic stability for these structures in rodents. Further optimization efforts resulted in analogs with improved potency, stability, and pharmacokinetic properties as well as good brain permeability, for example, compounds 26 and 42. Unexpected cytotoxicity was observed in such N-Me pyrazole structures as compounds 41-42.     

Bis(O2S2 macrocycle) complexes of palladium(II)

Two isomeric dibenzo-O₂S₂ macrocycles L¹ and L² have been synthesised and their coordination chemistry towards palladium(II) has been investigated. Two-step approaches via reactions of 1:1-type complexes, [cis-Cl₂LPd] (1a: L = L¹, 1b: L = L²), with different O₂S₂ macrocycle systems (L¹ and L²) have led to the isolation of the following bis(O₂S₂ macrocycle) palladium(II) complexes in the solid state: [Pd(L¹)₂](ClO₄)₂ (2a) and a mixture of [Pd(L¹)₂](ClO₄)₂ (2a) + [Pd(L²)₂](ClO₄)₂ (2b).     

Synthesis and characterisation of new molybdenum - oxo complexes containing diphenylphosphinylacetic acid and 2-(tert-butylsulphoxide)phenyldiphenylphosphine oxide as bidentate ligands

Reaction of the ligands diphenylphosphinylacetic acid Ph₂P(O)CH₂COOH (1) and 2-(tert-butylthio)phenyldiphenylphosphine oxide Ph₂P(O)C₆H₄^tBuS (2) with “MoO₂Cl₂”, resulted in two complexes MoO₂Cl₂Ph₂P(O)CH₂COOH (3) and MoO₂Cl₂Ph₂P(O)C₆H₄^tBuS(O) (4). Complexes 3 and 4 were isolated and analysed by ¹H NMR, ³¹P NMR and X-ray crystallography. Complex 3 crystallised with a molecule of the free ligand in a 1:1 ratio (3·1) and complex 4 crystallised with molecules of the solvent CH₂Cl₂ within the unit cell in a 2:1 ratio (4·0.5CH₂Cl₂). Tetrameric arrangements comprised of hydrogen bonds were observed in complexes 1 and 3. Complex 4 exhibited a seven-membered ring structure owing to the oxidation of the sulphide in 2 to sulphoxide and coordination of this ligand via the oxygen atoms to the molybdenum atom.     

Coordination compounds of Cd(II) with several bidentate-NN′ and tridentate-NN′N nitrogen donor ligands. Cd NMR studies of monomeric compounds containing nitrogen donor atoms

Reaction of CdCl₂ with N-alkylaminopyrazole ligands 1-[(2-ethylamino)ethyl]-3,5-dimethylpyrazole (deae), 1-[(2-(tert-butylamino)ethyl)]-3,5-dimethylpyrazole (deat), bis-[(3,5-dimethylpyrazolyl)methyl]ethylamine (bdmae), and bis-[(3,5-dimethylpyrazolyl)ethyl]ethylamine (ddae) in absolute ethanol yields [CdCl₂(NN′)] (NN′ = deae (1), deat (2)), [CdCl₂(bdmae)] (3), and [CdCl(ddae)]₂[CdCl₄] (4). The Cd(II) complexes have been characterised by elemental analyses, conductivity measurements, IR, ¹H, ¹³C{¹H} and ¹¹³Cd NMR spectroscopies, and X-ray diffraction methods. ¹H and ¹¹³Cd NMR experiments at variable temperature for 3 and 4 show that dynamic processes are taking place in solution. We report the measurements of ¹¹³Cd NMR chemical shift data for complexes 1-4 in solution. X-ray crystal structures for complexes 2 and 3 have been determined. The Cd(II) is coordinated to the deat ligand, in 2, by one nitrogen atom of the pyrazolyl group and one nitrogen atom of the amine. It finishes a tetrahedral geometry with two chlorine atoms. The bdmae ligand is linked to Cd(II), in 3, by two nitrogens atoms of the pyrazolyl groups and one amine nitrogen, along with two chlorine atoms, in a distorted trigonal bipyramidal geometry.     

Allosteric modulators of human A2B adenosine receptor

Background

Among adenosine receptors (ARs) the A_2B subtype exhibits low affinity for the endogenous agonist compared with the A₁, A_2A, and A₃ subtypes and is therefore activated when concentrations of adenosine increase to a large extent following tissue damages (e.g. ischemia, inflammation). For this reason, A_2B AR represents an important pharmacological target.

Methods

We evaluated seven 1-benzyl-3-ketoindole derivatives (7–9) for their ability to act as positive or negative allosteric modulators of human A_2B AR through binding and functional assays using CHO cells expressing human A₁, A_2A, A_2B, and A₃ ARs.

Results

The investigated compounds behaved as specific positive or negative allosteric modulators of human A_2B AR depending on small differences in their structures. The positive allosteric modulators 7a,b and 8a increased agonist efficacy without any effect on agonist potency. The negative allosteric modulators 8b,c and 9a,b reduced agonist potency and efficacy.

Conclusions

A number of 1-benzyl-3-ketoindole derivatives were pharmacologically characterized as selective positive (7a,b) or negative (8c, 9a,b) allosteric modulators of human A_2B AR.

General significance

The 1-benzyl-3-ketoindole derivatives 7–9 acting as positive or negative allosteric modulators of human A_2B AR represent new pharmacological tools useful for the development of therapeutic agents to treat pathological conditions related to an altered functionality of A_2B AR.     

Triorganotin(IV) complexes of Schiff base derived from 6-amino-2-mercaptobenzothiazole: Synthesis, characterization and X-ray crystal structures

Nine triorganotin(IV) complexes of the type R₃SnL (L = L1 R = Me 1, Ph 2, PhCH₂3; L = L2 R = Me 4, Ph 5, PhCH₂6; L = L2 R = Me 7, Ph 8, PhCH₂9) have been obtained by reaction of new Schiff base HL1, HL2 or HL3 with triorganotin(IV) chloride in the presence of sodium ethoxide. All the complexes 1-9 were characterized by elemental, IR and NMR spectra analyses. Except for complexes 3, 4, 6, 9, the others were also characterized by X-ray crystallography diffraction analyses, which revealed that complexes 1, 2, 5, 7, 8 were four coordinated and displayed a capped tetrahedron.     

Mn(II) coordination architectures with mixed ligands of 3-(2-pyridyl)pyrazole and carboxylic acids bearing different secondary coordination donors and pendant skeletons

In our efforts to investigate the factors that affect the formation of coordination architectures, such as secondary coordination donors and pendant skeletons of the carboxylic acid ligands, as well as H-bonding and other weak interactions, two kinds of ligands: (a) 3-(2-pyridyl)pyrazole (L¹) with a non-coordinated N atom as a H-bonding donor, a 2,2′-bipyridyl-like chelating ligand, and (b) four carboxylic ligands with different secondary coordination donors and/or pendant skeletons, 1,4-benzenedicarboxylic acid (H₂L²), 4-sulfobenzoic acid (H₂L³), quinoline-4-carboxylic acid (HL⁴) and fumaric acid (H₂L⁵), have been selected to react with Mn(II) salts, and five new complexes, [Mn(L¹)₂(SO₄)]₂ (1), [Mn(L¹)₂(L²)]_∞ (2), [Mn(L¹)(HL³)₂]_∞ (3), Mn(L¹)₂(L⁴)₂ (4), and [Mn(L¹)₂(L⁵)]_∞ (5), have been obtained and structurally characterized. The structural differences of 1-5 can be attributed to the introduction of the different carboxylic acid ligands (H₂L², H₂L³, HL⁴, and H₂L⁵) with different secondary coordination donors and pendant skeletons, respectively. This result also reveals that the typical H-bonding (i.e. N-H?O and O-H?O) and some other intra- or inter-molecular weak interactions, such as C-H?O weak H-bonding and π?π interactions, often play important roles in the formation of supramolecular aggregates, especially in the aspect of linking the multi-nuclear discrete subunits or low-dimensional entities into high-dimensional supramolecular networks.     

Dopamine release and molecular modeling study of some coumarin derivatives

4-aryl-2-amino-6-(4-hydroxy-2-oxo-2H-chromen-3-yl)-pyridin-3-carbonitrile (1), 4-aryl-2-oxo-6-(4-hydroxy-2-oxo-2H-chromen-3-yl)-pyridin-3-carbonitriles (2a-2c), 3-(6-aryl-1,2,5,6- tetrahydro-2-thioxopyrimidin-4-yl)-4-hydroxy-2H-chromen-2-one (3a, 3b) and pyrazol-3-yl-4-hydroxycoumarin derivatives (4a-4c, 5, 6a, 6b, 7a, 7b, and 8a-8c) were prepared in order to measure their % change dopamine release in comparison to amphetamine as reference, using PC-12 cells in different concentrations. In addition, the molecular modeling study of the compounds into 3BHH receptor was also demonstrated. The calculated inhibition constant (k_i) implemented in the AutoDock program revealed identical correlation with the experimental results to that obtained binding free energy (ΔG_b) as both parameters revealed reasonable correlation coefficients (R²) being 0.51 involving 10 compounds; (1, 2b, 2c, 3a, 3b, 4a, 4b, 6a, and 8c).     

The novel 3,4-dihydropyrimidin-2(1H)-one urea derivatives of N-aryl urea: synthesis, anti-inflammatory, antibacterial and antifungal activity evaluation

A series of novel 3,4-dihydropyrimidin-2(1H)-one urea derivatives of biological interest were prepared by sequential Bigineli’s reaction, reduction followed by reaction of resulting amines with different arylisocynates. All the synthesized (1-23) compounds were screened against the pro-inflammatory cytokines (TNF-α and IL-6) and antimicrobial activity (antibacterial and antifungal). Biological activity evaluation study reveled that among all the compounds screened, compounds 12 and 17 found to have promising anti-inflammatory activity (68-62% TNF-α and 92-86% IL-6 inhibitory activity at 10 μM). Interestingly compounds 3, 4, 5, 6, 15, 22 and 23 revealed promising antimicrobial activity at MIC of 10-30 μg/mL against selected pathogenic bacteria and fungi.     

Ecdysteroids from Polypodium vulgare L

Three new compounds (3, 7, and 11) together with eight known phytoecdysteroids (1, 2, 4-6, and 8-10) were isolated from the rhizomes of common polypody, Polypodium vulgare L. The structures of compounds were elucidated by spectroscopic methods including 1D and 2D NMR measurements. The ¹H and ¹³C NMR assignments of compounds 1, 6, 9 and 10 are included.     

Triterpenoid saponins from Echinopsis macrogona (Cactaceae)

Triterpene saponins, pachanosides C1, E1, F1 and G1 (1-4), and bridgesides A1, C1, C2, D1, D2, E1 and E2 (5-11) were isolated from Echinopsis macrogona. Compounds 1-4 were saponins with pachanane type triterpene saponins, while the others (5-11) were oleanane type triterpene saponins. While the aglycones of 2-4 and 8-11 were hitherto unknown, the structure of pachanol C was revised in this paper. Their structures were elucidated on the basis of chemical and physicochemical evidence.     

Synthesis and antimicrobial activity of some new N-glycosides of 2-thioxo-4-thiazolidinone derivatives

5-Arylidene-2-thioxo-4-thiazolidinones 3a-f react with each of 2,3,4,6-tetra-O-acetyl-α-d-glucopyranosyl and α-d-galactopyranosyl bromides 4a,b in acetone in the presence of aqueous potassium hydroxide at room temperature to afford N-(2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyl) or N-(2,3,4,6-tetra-O-acetyl-β-d-galactopyranosyl) 2-thioxo-4-thiazolidinone derivatives 5a-f. Similarly, the reaction of 5-cycloalkylidene-2-thioxo-4-thiazolidinones 7a,b with 4a gave the corresponding N-glucosides 8a,b. Also, 5-pyrazolidene rhodanines 10a-e react with 4a to afford the new N-glucosides 11a-e. Treatment of compounds 15 and 16 with 4a in the presence of few drops of triethylamine or in KOH solution accomplished the mono- and bis-nucleosides 17 and 18, respectively. Some selected products were tested for their antimicrobial activities.     

Synthesis, modification, and evaluation of (R)-de-O-methyllasiodiplodin and analogs as nonsteroidal antagonists of mineralocorticoid receptor

Macrolide (R)-de-O-methyllasiodiplodin (1), discovered to be a potent nonsteroidal antagonist of the mineralocorticoid receptor (MR), was synthesized via an efficient method and evaluated for MR antagonistic activity together with its analogs. Among all the tested compounds, compounds 18a, 18b and 18c, exhibited more potent antagonistic activity against MR with IC₅₀ values ranging from 0.58 to 1.11 μM. Generally, it was obviously demonstrated that acetylation at phenolic hydroxyl groups and the ring size in analogs of 1 were very important for MR antagonist activity.     

Palladium(II), platinum(II), ruthenium(II) and mercury(II) complexes of potentially tridentate Schiff base ligands of (E, N, O) type (E = S, Se, Te): Synthesis, crystal structures and applications in Heck and Suzuki coupling reactions

Schiff bases of 2-hydroxybenzophenone (HBP) (C₆H₅)(2-HOC₆H₄)CN(CH₂)_nEAr (L1/L2: E = S, Ar = Ph, n = 2/3; L3/L4: E = Se, Ar = Ph, n = 2/3; L5/L6: E = Te, Ar = 4-MeOC₆H₄, n = 2/3) and their complexes [PdCl(L-H)] (L = L1−L6; 1, 2, 3, 5, 7, 11), [PtCl(L3-H/L5-H)] (4/8), [PtCl₂(L4/L6)₂] (6/12), [(p-cymene)RuCl(L5/L6)]Cl (9/13) and [HgBr₂(L5/L6)₂] (10/14) have been synthesized and characterized by proton, carbon-13, selenium-77 and tellurium-125 NMR, IR and mass spectra. Single crystal structures of L1, 1, 3, 4, 5 and 7 were solved. The Pd-E bond distances (Å): 2.2563(6) (E = S), 2.3575(6)−2.392(2) (E = Se); 2.5117(5)−2.5198(5) (E = Te) are near the lower end of the bond length range known for them. The Pt-Se bond length, 2.3470(8) Å, is also closer to the short values reported so far. The Heck and Suzuki reaction were carried out using complexes 1, 3, 5 and 7 as catalysts under aerobic condition. The percentage yields for trans product in Heck reaction were found upto 85%.     

β-Diiminatolanthanoid(III) halides revisited

The crystalline compounds [LnCl₂(L)(thf)₂] [Ln = Ce (1), Tb (2), Yb (3)], [NdI₂(L)(thf)₂] (4), [LnCl(L′)₂] [Ln = Tb (5), Yb (6) (a known compound)] and [YbCl(L′′)(μ-Cl)₂Li(OEt₂)₂] (7) have been prepared [L = {N(C₆H₃Prⁱ₂-2,6)C(H)}₂CPh, L′ = {N(SiMe₃)C(Ph)}₂CH, L′′ = {N(SiMe₃)C(C₆H₄Ph-4)}₂CH]. The X-ray molecular structures of 2-7 have been established; in each, the monoanionic ligand L, L′ or L′′ is N,N′-chelating and essentially π-delocalised. Each of 1-7 was prepared from the appropriate LnCl₃, or for 4 [NdI₃(thf)₂], and an equivalent portion of the appropriate alkali metal [Li for 7, Na for 2, 3 and 5, or K for 1, 4 and 6] β-diiminate in thf; the isolation of exclusively 5 and 6 (rather than the L′ analogues of 2 or 3) is noteworthy, as is the structure of 7 which has no precedent in Group 3 or 4f metal β-diiminato chemistry.     

Spirodiketopiperazine-based CCR5 antagonist: discovery of an antiretroviral drug candidate

Following the discovery that hydroxylated derivative 3 (Fig. 1) was one of the oxidative metabolites of the original lead 1, it was found that hydroxylated compound 4 possesses higher in vitro anti-HIV potency than the corresponding non-hydroxylated compound 2. Structural hybridation of 4 with the orally available analog 5 resulted in another orally-available spirodiketopiperazine CCR5 antagonist 6a that possesses more favorable pharmaceutical profile for use as a drug candidate.     

Chemical constituents from fruits of Harrisonia perforata

Eight limonoids (1-8) including three A, B and D-seco-16-nor-type ones, 5,6-dehydrodesepoxyharperforin C2 (1), harrpernoid B (2), and its C-9S epimer, harrpernoid C (3), along with six known compounds (9-14), were isolated from fruits of Harrisonia perforata. Extensive spectroscopic analysis was used to elucidate their structures and stereochemistries. Further confirmation of structures of 1 and 2 were obtained by single-crystal X-ray diffraction. Limonoids (1-8) were evaluated for their anti-tobacco mosaic virus activity and in vitro cytotoxicity against A549 and HL60 cell lines; only compound 2 showed weak activity.