20854-60-8

Deployment of reduced operational temperatures is industrially beneficial and use of the highly efficient, phosphine-based precatalysts is limited by their high costs and inaccessible preparation procedures. In order to study of the influence of coordination environments on catalyst reactivities at reduced temperatures, design of palladium(II) complexes bearing single monodentate N-donor ligands was considered necessary. Consequently, dichloridopalladium(II) complexes of 2-(thiophen-2-yl)-1H-imidazole ligands (1–8), 2,4,5-triphenyloxazole (9) and 2-(1H-imidazol-2-yl)pyridine (10) have been prepared, structurally characterized and studied as N-stabilized precatalysts. Ligand donor strengths were spectroscopically estimated by protonation-deprotonation equilibria. The palladium(II) complexes were obtained in three coordination environments; (i) the mono-ligand complexes bearing trans-solvent co-ligands (PdL.acn and PdL.dmf), (ii) the chlorido-bridged dimers μ-(PdL)2 and (iii) the trans-bis-ligand PdL2 complexes. Considering ambient temperature operations, the catalysis outcomes obtained for the monodentate mono-ligand coordination designs represent an improvement in terms of temperature and reaction time relative to previously reported N-stabilized palladium precatalysts. The mono-ligand pre-catalysts efficiently generate living active palladium species from 40 °C while a trans-bis-ligand phosphine-based pre-catalyst analogue PdI2(PPh3)2 displayed no yield under the same temperature conditions. Trans-bis-ligand coordination is observed to utterly hinders catalyst efficiencies at the studied temperatures and preformed mono-ligand complexes of mono-dentate N-donors provided positive ligand effects while in situ catalyst generation failed. Therefore, the use of multiple ligand equivalents should be discouraged.

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Four probes based in the use of a biphenyl moiety and functionalized with trimethylsilyl benzyl ether (P1 and P3) and oxime (P2 and P4) groups have been prepared and tested as optical probes for the detection of NO2. Reaction of NO2 with acetonitrile solutions of P2-P4 resulted in the formation of aldehydes 7 and 8 with a concomitant redshift of the absorption bands. Probe P2 displayed a bathochromic shift of 45 nm upon reaction with NO2 and was able to detect this poisonous gas at concentrations as low as 0.02 ppm. P2 was highly selective against NO2 and other gases (i.e. NO, CO2, H2S, SO2) and vapours of organic solvents (i.e. acetone, hexane, chloroform, acetonitrile or toluene) had no effect in the optical properties of the probe.

Covalent organic frameworks (COFs) are an emerging class of crystalline porous polymers that make these materials suitable for use as excellent scaffold in heterogeneous catalysis. Here we synthesize a layered two-dimensional (2D) COF (TADP-COF) through the condensation reaction between four-branched 5,10,15,20-tetrakis(4-aminophenyl)porphyrin (TAPP) and linear 2,5-dihydroxyterephthalaldehyde (Dha) and 1,4-phthalaldehyde (PA) building blocks. Porphyrin units, imine and hydroxyl groups together with imines can provide wide coordination sites for metal docking. Using a programmed synthetic procedure, Cu(ii) ions first coordinated with the imine groups in conjunction with their adjacent hydroxyl groups, and porphyrin units and subsequently added Pd(ii) ions occupied the remaining imine sites in the space between adjacent COF layers. The bimetallic Pd(ii)/Cu(ii)@TADP-COF showed high catalytic activity in a one-pot coupling/oxidation cascade reaction in water. The high surface area, one-dimensional (1D) open channel structure and predesigned catalytic active sites of this material make it ideal candidate for use as heterogeneous catalyst in a wide range of catalytic reactions.

A series of six new, bidentate ligands based on N-(2-(R-sulfonamido)benzyl)R-sulfonamide have been isolated as dianionic or monoanionic chelators via condensation of 2-(aminomethyl)aniline with sulfonyl chloride reagents; R = methyl (1 and 1′), tolyl (2 and 2′), 2,4,6-Trimethylphenyl (3), or 2,4,6-Triisopropylphenyl (4). Complexes of ligands 2-4 reacted at room temperature with palladium(ii) acetate in the presence of various monodentate N-donor co-ligands to form complexes Pd2(2dmap), Pd2′(OAc.py), Pd3(2acn), Pd3(2py), Pd4(2acn), and Pd4(2py), which were structurally confirmed by three X-ray crystal analyses. Results of catalysis studies in water showed high turnover frequencies and yields of up to 98 % within 10 min and at 0.2 mol-% palladium catalyst loading. Relative to ligand-free catalysis in the presence of only Pd(OAc)2, the ligand-supported palladium species clearly possess positive catalytic advantage. Furthermore, Suzuki coupling efficiencies by 1: 1 'Pd(OAc)2 + ligand' yielded notably better outcomes than for the 1: 2 'Pd(OAc)2 + ligand' in situ catalyst generation, which reveals that coordinative saturation is undesirable. The size of the complementing monodentate co-ligand was observed to influence the catalytic efficiency such that bulkier co-ligands consistently yielded improved turnover frequency values, which leads to the conclusion that steric repulsion between the synthesised ligands and the bulkier co-ligands aided the generation of vacant coordination sites for the more active complexes. Moderate Heck coupling activity was recorded for the complexes and better activities appear to correlate with moderate bulkiness of ligand 3.

An atom-efficient procedure for the synthesis of functionalized biarylmethanols via the Pd-catalyzed cross-coupling reactions of differently functionalized iodophenylmethanols and triarylbismuth reagents is described. This protecting group-free direct couplings of 2-, 3- or 4-iodophenylmethanols with triarylbismuth reagents afforded biarylmethanols in good to high yields.

In this report, a series of synthetically affordable phosphine-free ligands (L1 – L4) of the form RSO2–NH–Ph–N[dbnd]N–Ph–NH–SO2R were prepared and examined as organic ligands for stabilizing palladium active centers; R = methyl, tolyl or triiso-propylphenyl. Palladium complexes, which were obtained in varying coordination environments as well as with varying complementary co-ligands (water, acetonitrile or pyridine), have been subjected to Suzuki and Heck coupling experiments in order to study molecular level ligand effects on preferred catalyst settings. The appreciable coupling activities for Suzuki and Heck coupling with functional group tolerance were recorded for palladium species generated from the chelate ligands. Results show that, despite the tridentate chelation characteristics of these azo-benzene ligands, the introduction of bulky units at the sulfonyl groups enabled generation of active palladium species with high turnover frequencies; e.g. 5040 h?1 (84% yield) within 5 min at 0.2 mol % loading of Pd.L2.py in only water as solvent. A correlation between catalytic efficiencies and the bulkiness of the coordinated co-ligand was obtained. However, while Suzuki coupling activity increased with increase in co-ligand sizes of the preformed complexes (i.e. water acetonitrile pyridine), the pyridyl co-ligand turned out to be very unfavourable for Heck coupling where the acetonitrile-complemented complexes possessed the higher activities. Therefore, it could be concluded that the best catalyst setting for Suzuki coupling may not be the best for Heck reaction.

Unfriendly temperature profiles and costs of carbon coupling catalysis, which pose challenge to both synthetic organic chemists as well as industrial applicability, motivated our design of new monodentate N-donors as support ligands for the purpose of constructing ambient temperature precatalysts that are molecularly close to the hypothetical active forms. Therefore, a series of sterically varied monodentate N-donor imidazoles (1–7) and oxazoles (8–9) have been synthesized and their N-donor strengths, which were estimated as pKas, are systematically varied from 0.9 to 8.5 by substituent variations. Eleven target mono-ligand complexes (1-PdCl2MeCN – 9-PdCl2MeCN, 6-PdCl2PhCN and 7-PdCl2PhCN) and six trans-bis-ligand complexes (12-PdCl2, 22-PdCl2, 32-PdCl2, 62-PdCl2, 12-Pd(OAc)2 and 22-Pd(OAc)2) were isolated and catalytically studied along with PdI2(PPh3)2. Results of coupling reactions, which were conducted both via in situ ‘Pd(II) salt + ligand’ approach and by use of the precatalysts, show that the mono-ligand precatalyst designs (1-PdCl2MeCN – 9-PdCl2MeCN, 6-PdCl2PhCN and 7-PdCl2PhCN) represent a true catalyst improvement initiative among the phosphine-free catalyst community; i.e. yields approaching 100% (TOF ≈ 2000) at 0.2 mol % catalyst loading, 45 °C and within 15 min. On the other hand, the complexes with trans-bis-ligand coordination were inactive at ambient temperatures. Therefore, it was concluded that coordinative saturation, which results from implementing two or more ligand equivalents or use of polydentate ligands on palladium, should be strongly discouraged. Such saturation necessitates the undesirable and avoidable high temperature necessities, long reflux durations and needlessly high catalyst loadings. Correlation between catalyst activity and donor strengths or steric properties were analysed leading to important conclusions. The catalyst design also supported coupling of activated aryl chlorides from 60 °C while Heck coupling activities were observed only at the early minutes of reactions.

A series of synthetically accessible ligands based on new 2-(R-sulfonamido)benzamide have been prepared (R = methyl for H3M; R = 4-toly for H3T and T2CN; R = 2,4,6-triisopropylphenyl for H3iP and HiPCN). The R-substituents were selected to vary in sizes. Allowing ligand H3iP and palladium acetate to stand in solvent leads to self-assembly of the well-defined solvent- and stoichiometry-controlled tetranuclear or hexanuclear coordination macromolecules Pd4(iP)2 and (PdHiP)6, which were analysed by X-ray crystallography. It was observed that palladium active species for Suzuki coupling catalysis could be stabilized by these simple and synthetically assessable N-donor ligands as revealed by turnover frequencies reaching 5500 h?1. Electronic features of these N-donors appear to be more important than the steric properties.

The spread of drug-resistant malaria parasites urges the search for new antimalarial drugs. Malarial aspartic proteases – plasmepsins (Plms) – are differentially expressed in multiple stages of the Plasmodium parasite's lifecycle and are considered as attractive drug targets. We report the development of novel azole-based non-peptidomimetic plasmepsin inhibitors that have been designed by bioisosteric substitution of the amide moiety in the Actelion amino-piperazine inhibitors. The best triazole-based inhibitors show submicromolar potency toward Plm II, which is comparable to that of the parent Actelion compounds. The new inhibitors can be used as a starting point for the development of a resistance-free antimalarial drug targeting the non-digestive Plm IX or X, which are essential for the malaria parasite life cycle.

The present invention relates to novel aminoalkylazoles acting as inhibitors of malarial protease plasmepsin II. These can be used as medicines or as constituent of medicines for the treatment of malaria infection.

Two water-soluble monophosphine [PPh3 and 2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl(Sphos)]-palladacycles containing hydroxymethyl groups 2-3 were prepared by cyclopalladation and chloride bridge-splitting reactions. The complexes were characterized by elemental analysis, ESI-MS and NMR. In addition, single-crystal X-ray analysis reveals that they have one-dimensional lamellar structures involving intermolecular hydrogen bonds and π-π interactions. The use of these palladacycles as catalysts for amination and Suzuki coupling of aryl chlorides in water was investigated. Complex 3 was found to be very efficient for these coupling reactions. Additionally, it was also successfully used in Suzuki coupling of (hydroxymethyl)phenylboronic acid for the synthesis of substituted 2-N-heterocyclic biarylmethanols.

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N-Heterocyclic carbene-based pincer nickel complexes were synthesized and characterized. These complexes efficiently catalyze cross-coupling of aryl Grignard reagents with aryl chlorides or fluorides under mild conditions.

Disclosed are compounds of formula (I) and or salts thereof which activate soluble guanylate cyclase (sGC), pharmaceutical compositions containing them, their use in the manufacture of a medicament for teating cardiovascular diseases, and processes for their preparation.

Disclosed are compounds of formula (I) wherein R1 and R2 are independently selected from hydrogen, halo, C1-4alkyl, C1-4alkoxy, CF3 and OCF3; -Y- represents formula (IA) R3 represents hydrogen, fluoro, chloro or C1-4alkyl; R4a and R4b each independently represent hydrogen, C1-4alkyl, C1-4alkoxy, CF3 or halo; and R5 represents a group Z-X; wherein Z is absent or represents (CH2)2 or O; and X represents formula (IB) wherein: J and L both represent CH, or one of J and L represents CH and the other represents N; when both J and L represent CH, R6 represents hydrogen, halo, CF3, C1-4alkyl or C1-4alkoxy in a meta or ortho position relative to the R7 substituent and R7 represents hydrogen, halo, CF3, OCF3, C1-4alkyl, C1-4alkoxy, CH2OH, CN, CONR8R9 or CO2H; or when one of J or L represents N, R6 represents hydrogen or halo in a meta or ortho position relative to the R7 substituent and R7 represents hydrogen, halo, CF3, C1-4alkyl, C1-4alkoxy, CH2OH, CN, CONR8R9 or CO2H; and R8 and R9 are independently selected from hydrogen and C1-4alkyl; or salts thereof which activate soluble guanylate cyclase (sGC), pharmaceutical compositions containing them, their use in medicine, and processes for their preparation.

Disclosed are compounds of formula (I) wherein R1 and R2 are independently selected from hydrogen, halo, CF3, C1-4alkyl and allyl; Y represents (II), (III), (IV) or (V) wherein R3 represents CF3 or C1-4alkyl; and R3a represents CF3 or C1-4alkyl.

The synthesis of 4′-hydroxy-4-biphenylpropionic, 3′,4′- dihydroxy-4-biphenylpropionic, 3′,5′-dihydroxy-4-biphenylpropionic, and 3′,4′,5′-trihydroxy-4-biphenylpropionic methyl esters via three efficient and modular strategies including one based on Ni-catalyzed borylation and sequential cross-coupling is reported. These building blocks were employed in a convergent iterative approach to the synthesis of one library of 3,4,5-trisubstituted and two libraries of constitutional isomeric 3,4- and 3,5-disubstituted biphenylpropyl ether dendrons. Structural and retrostructural analysis of supramolecular dendrimers revealed that biphenylpropyl ether dendrons self-assemble and self-organize into the same periodic lattices and quasi-periodic arrays observed in previously reported libraries, but with larger dimensions, different mechanisms of self-assembly, and improved solubility, thermal, acidic, and oxidative stability. The different mechanisms of self-assembly led to the discovery of two new supramolecular structures. The first represents a new banana-like lamellar crystal with a four layer repeat. The second is a giant vesicular sphere self-assembled from 770 dendrons that exhibits an ultrahigh molar mass of 1.73 × 106 g/mol. Thus, the enhanced size of the self-assembled structures constructed from biphenylpropyl ether dendrons permitted for the first time discrimination of various molecular mechanisms of spherical self-assembly and elaborated a continuum between small filled spheres and very large hollow spheres that is dictated by the primary structure of the dendron. The comparative analysis of libraries of biphenylpropyl ether dendrons with the previously reported libraries of benzyl-, phenylpropyl-, and biphenyl-4-methyl ether dendrons demonstrated biomimetic self-assembly wherein the primary structure of the dendron and to a lesser extent the structure of its repeat unit determines the supramolecular tertiary structure. A "nanoperiodic table" of self-assembling dendrons and supramolecular dendrimers that allows the prediction of the general features of tertiary structures from primary structures was elaborated.

A compound of the formula (I): wherein X1 and X2 are the same or different and each is a bond or a spacer having 1 to 20 atom(s) in the main chain; one of R1 and R2 is a cycle group having substituent(s) selected from 1) an optionally substituted carboxy-C1-6 alkoxy group and 2) an optionally substituted carboxy-C1-6 aliphatic hydrocarbon group, wherein the cycle group optionally has additional substituent(s), and the other is an optionally substituted cycle group or a hydrogen atom; and R3, R4 and R5 are the same or different and each is a hydrogen atom or a substituent, or R4 may link together with R3 or R5 to form an optionally substituted ring; provided that when R3 is a hydrogen atom, R4 is a hydrogen atom and R5 is methyl, X2—R2 is not 4-cyclohexylphenyl; when R3 is 4-methoxyphenyl, R4 is a hydrogen atom and R5 is methyl, X2—R2 is not 4-methoxyphenyl; and when R1 or R2 is a hydrogen atom, the adjacent X1 or X2 is not a C1-7 alkylene; or a salt thereof exhibits a protein tyrosine phosphatase inhibitory action and is useful as a prophylactic or therapeutic agent for diabetes or the like.

The synthesis of three liquid crystals with the general formula N,N'-bis(p-alkoxyphenylbenzylidene)-α,α'-bi-p-toluidine where the alkoxy group is represented by methoxy (BABT; nematic range of 253-370 deg C), n-butoxy (BBPT; nematic range of 232-331 deg C), and benzyloxy (BBzPT; nematic range 270-346 deg C) is reported.The liquid crystals were synthesized by the condensation of the appropriate 4'-alkoxybiphenyl-4-carboxaldehyde with α,α'-bi-p-toluidine.The aldehydes were prepared by a five-step procedure starting with 4-hydroxybiphenyl.BABT was chromatographically evaluated.BABT operating in the supercooled nematic region at 230 deg deg C provided better separations of methylbenzanthracene isomers than conventional SE-30, Dexsil 300, and Silicon Gum MS2211 columns.