The Structure of Maneb, An Important Manganese-Containing Bis(dithiocarbamate) Fungicide.

Maneb is a manganese(II)-containing fungicide with a multi-site effect and no resistance, therefore it is widely applied in many parts of the world. There is, however, mounting evidence for neurotoxic effects with Parkinson-like symptoms (manganism) related to usage of Maneb. Due to its insolubility in most solvents and its paramagnetism, structural elucidation is not trivial, and thus its exact molecular structure remains unknown. We report herein a synthesis procedure to prepare Maneb reproducibly in pure form and the use of various analytical techniques including X-ray diffraction, X-ray absorption spectroscopy and electron diffraction to determine the molecular structure of Maneb in the solid state and also in solution.

Facile N9-Alkylation of Xanthine Derivatives and Their Use as Precursors for N-Heterocyclic Carbene Complexes.

The xanthine-derivatives 1,3,7-trimethylxanthine, 1,3-dimethyl-7-benzylxanthine and 1,3-dimethyl-7-(4-chlorobenzyl)xanthine are readily ethylated at N9 using the cheap alkylating agents ethyl tosylate or diethyl sulfate. The resulting xanthinium tosylate or ethyl sulfate salts can be converted into the corresponding PF6- and chloride salts. The reaction of these xanthinium salts with silver(I) oxide results in the formation of different silver(I) carbene-complexes. In the presence of ammonia, ammine complexes [Ag(NHC)(NH3)]PF6 are formed, whilst with Et2NH, the bis(carbene) salts [Ag(NHC)2]PF6 were isolated. Using the xanthinium chloride salts neutral silver(I) carbenes [Ag(NHC)Cl] were prepared. These silver complexes were used in a variety of transmetallation reactions to give the corresponding gold(I), ruthenium(II) as well as rhodium(I) and rhodium(III) complexes. The compounds were characterized by various spectroscopic methods as well as X-ray diffraction.

Synthesis, Reactivity and Antimicrobial Activity of a Series of 2-Arylamino-1,3-selenazoles.

A series of 2-arylamino-1,3-selenazoles was synthesized and their reactivity was studied. The 2-arylamino-1,3-selenazoles and their reaction products were characterized by various spectroscopic methods and X-ray diffraction. In addition, the antimicrobial activity of the 2-arylamino-1,3-selenazoles in a panel of seven bacteria and fungi was examined.

Ring Expansion of 2-Azido-2-phenyl-indan-1,3-dione for the Generation of Heterocyclic Scaffolds.

A novel ring expansion based on the readily available 2-azido-2-phenyl-indan-1,3-dione is described. Treatment with primary amines and cesium carbonate in a two-step sequence gives rise to 3-amino-2,3-dihydroisoquinoline-1,4-diones with an unprecedented substitution pattern. The corresponding conversion using amino acid methyl esters leads directly to a novel tricyclic 1,10a-dihydroimidazo-isoquinoline-2,5,10-trione scaffold, a structure that has never been reported before, to the best of our knowledge.

Silver(I) Complexes with Camphorsulfonato and Phosphine Ligands: Structural Diversity and Antibacterial Activity.

A series of silver(I) camphorsulfonato complexes containing various phosphine ligands having the stoichiometry [Ag(camphSO3)(PR3)] [PR3 = PTA (1,3,5-triaza-7-phosphaadamantane), PASO2 (2-thia-1,3,5-triaza-7-phosphaadamantane-2,2-dioxide), PPh3, PCy3, P(CH2CH2CN)3, PPyPh2, or P(o-tol)3] were prepared and fully characterized by NMR spectroscopic methods and X-ray crystallography. Depending on the nature of the phosphine, a variety of different supramolecular structures, including dimers, macrocycles, and coordination polymers, were observed in the solid state. The in vitro antimicrobial activity in seven different pathogens (Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii, Candida albicans, and Cryptococcus neoformans var. grubii) as well as toxicity in human cells was also examined. While all compounds show some activity against the bacteria, they were especially active against the fungus C. neoformans. The most active and at the same time least toxic compound was found to be the water-soluble complex [Ag(camphSO3)(PTA)2].

A Synthetic Route Toward Tetrazoles: The Thermolysis of Geminal Diazides.

A new synthetic route toward the tetrazole core is described, which is based on a general fragmentation pattern that was found in a range of compounds featuring geminal diazido units. Through a simple two-step procedure, the synthesis of structurally diverse target compounds containing a tetrazole, such as tetrazoloquinoxalinones, benzoylaryltetrazoles, tetrazolotriazinones, and tetrazoloazepinones, was easily accomplished, starting from broadly accessible substrates (i.e., oxindoles, diarylethanones, pyrazolones, and phenanthrols). The initial oxidative diazidation reaction with iodine and sodium azide under mild conditions is followed by the thermal fragmentation under microwave irradiation, leading to the tetrazole products. Noteworthy, an experimental solution is presented in which the potentially hazardous diazide intermediates are not isolated and the concentration of crude reaction mixtures containing diazides is not required to achieve the tetrazoles in good yields.

Minimally manipulated murine regulatory T cells purified by reversible Fab Multimers are potent suppressors for adoptive T-cell therapy.

The transfer of regulatory T cells, either freshly isolated, or modified, represents a promising therapeutic approach to dampen misdirected immune responses, like autoimmune diseases, chronic inflammatory syndromes and graft versus host disease. Clinical isolation of highly pure regulatory T cell (Treg) populations is still challenging and labeling reagents can influence their viability and functionality, potentially altering the potency of isolated Treg cell products. Here we show that reversible Fab multimer-based Treg purification can prevent conventional antibody label-induced interferences in vitro and in vivo. Remaining isolation reagents negatively interfere with Treg engraftment efficacy in C57BL/6 wild-type mice due to Fcγ-receptor- as well as IL-2 receptor-mediated mechanisms. Using a preclinical model for acute GvHD, we further show that purified 'label-freed' Tregs are protective at substantially lower cell numbers as compared to conventional nonreversible antibody staining, translating into significantly improved survival of mice treated with minimally manipulated Tregs. These findings have important clinical relevance for future Treg-based cell therapies.

Flow cytometry-based TCR-ligand Koff -rate assay for fast avidity screening of even very small antigen-specific T cell populations ex vivo.

High epitope-specific sensitivity of CD8(+) T cells is required for optimal immune protection against intracellular pathogens as well as certain malignancies. The quality of antigen recognition of CD8(+) T cells is usually described as "avidity" to its cognate peptide MHCI complex. T cell avidity is mainly dependent on the structural qualities of the T cell receptor (TCR), as convincingly demonstrated by recombinant TCR re-expression experiments. Based on reversible MHCI multimer staining and koff -rate measurements of monomeric peptide MHCI complexes, we recently established a microscopic assay for determining the structural avidity of individual CD8(+) T cells. Here we demonstrate that this assay can be adapted for rapid flow-cytometric avidity screening of epitope-specific T cell populations. Furthermore, we show that-in combination with conventional nonreversible MHCI multimer staining-even very small epitope-specific CD8(+) T cell populations can be analyzed directly ex vivo without the need for previous TCR cloning or T cell sorting. This simplified approach provides highly accurate mean TCR-ligand koff -rate values for poly- or oligoclonal T cell populations and is ideally suited for high-throughput applications in basic research as well as clinical settings. © 2016 International Society for Advancement of Cytometry.

Geminal Diazides Derived from 1,3-Dicarbonyls: A Protocol for Synthesis.

Geminal diazides constitute a rare class of compounds where only a limited number of methods are available for their synthesis. We present the reaction of 1,3-dicarbonyl compounds (as exemplified by malonates, 3-oxoesters, and 1,3-diketones) with molecular iodine and sodium azide in aqueous DMSO providing a general access to geminal diazides. A broad range of geminal diazides with various structural motifs including sterically demanding substituents and ordinary functional groups were synthesized, and it was shown that the diazidation of 1,3-dicarbonyls can be selectively achieved even in the presence of other 1,3-dicarbonyls with substituents at 2-position. Additionally, several diazides were studied regarding their thermal stability.

Exposure to the environmentally relevant fungicide Maneb: Studying toxicity in the soil nematode Caenorhabditis elegans.

Maneb is a manganese-containing ethylene bisdithiocarbamate fungicide and is still commonly used as no cases of resistance have been documented. However, studies have shown that Maneb exposure has neurodegenerative potential in mammals, resulting in symptoms affecting the motor system. Despite its extensive use, structural elucidation of Maneb has only recently been accomplished by our group. This study aimed to examine the bioavailability of Maneb, the quantification of oxidative stress-related endpoints and neurotransmitters employing pure Maneb, its metabolites and structural analogues, in the model organism Caenorhabditis elegans. Exposure to Maneb did not increase the bioavailability of Mn compared to manganese chloride, although Maneb was about 8 times more toxic with regard to lethality. Maneb generated not significantly reactive oxygen and nitrogen species (RONS) but decreased the ATP level while increasing the amount of glutathione and its oxidized form in a dose-dependent manner. Nevertheless, an alteration in the neurotransmitter homeostasis of dopamine, acetylcholine, and gamma-butyric acid (GABA) was observed as well as morphological changes in the dopaminergic neurons upon Maneb exposure, which underlines the assumption of the neurotoxic potential of Maneb. This study showed that Maneb exhibits effects based on a combined interaction of the ligand and manganese.

trans-thionate derivatives of Pt(II) and Pd(II) with water-soluble phosphane PTA and DAPTA ligands: antiproliferative activity against human ovarian cancer cell lines.

A series of PTA and DAPTA platinum(II) and palladium(II) thionate complexes of the type trans-[M(SN)2P2] were prepared from the reaction of cis-[MCl2P2] [M = Pt, Pd; P = PTA (1,3,5-triaza-7-phosphaadamantane), DAPTA (3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane)] with the in situ generated sodium salts of the heterocyclic thiones S-m-methylpyrimidine-2-thione, S-4,6-dimethylpyrimidine-2-thione, S-4,6-dihydroxypyrimidine-2-thione, benzothiazole-2-thione, benzoxazole-2-thione, S-1,3,4,-thiadiazole-2-thione, S-4,5-H-thiazolan-2-thione, and S-pyrimidine-4(1H)-one-2-thione. The X-ray structures of six of the compounds confirm the trans disposition and, only in the case of [Pd2Cl2(S-pyrimidine-4(1H)-one-2-thionate)2(PTA)2], a dinuclear structure with a Pd-Pd distance of 3.0265(14)Å was observed. In vitro cytotoxicities against human ovarian cancer cell lines A2780 and A2780cisR were evaluated for ten complexes showing a high inhibition of cellular growth with a comparable inhibitory potency (IC50) against A2780 cells to that of cisplatin. Notably, the compounds also show significant (up to 7-fold higher) activity in cisplatin-resistant A2780cisR cell lines.

Synthesis of mesomeric betaine compounds with imidazolium-enolate structure.

The synthesis of a heterocyclic mesomeric betaine by quaternization reaction of 1-butylimidazole and tetrabromo-1,4-benzoquinone is presented. The structure was verified by means of X-ray single-crystal analysis, NMR and IR spectroscopy. Inclusion complexes of the heterocyclic mesomeric betaine with randomly methylated (1.8) ß-cyclodextrin were investigated by UV-vis spectroscopy. Furthermore, the reaction conditions were applied to poly(vinylimidazole) and 1,4-bis(1H-imidazol-1-yl)butane to obtain functionalized polymer networks and condensate polymers, respectively.

TET3 promotes AML growth and epigenetically regulates glucose metabolism and leukemic stem cell associated pathways.

Acute myeloid leukemia (AML) is considered a poor prognosis malignancy where patients exhibit altered glucose metabolism and stem cell signatures that contribute to AML growth and maintenance. Here, we report that the epigenetic factor, Ten-Eleven Translocation 3 (TET3) dioxygenase is overexpressed in AML patients and functionally validated human leukemic stem cells (LSCs), is required for leukemic growth by virtue of its regulation of glucose metabolism in AML cells. In human AML cells, TET3 maintains 5-hydroxymethylcytosine (5hmC) epigenetic marks and expression of early myeloid progenitor program, critical glucose metabolism and STAT5A signaling pathway genes, which also positively correlate with TET3 expression in AML patients. Consequently, TET3 depletion impedes hexokinase activity and L-Lactate production in AML cells. Conversely, overexpression of TET3 in healthy human hematopoietic stem progenitors (HSPCs) upregulates the expression of glucose metabolism, STAT5A signaling and AML associated genes, and impairs normal HSPC lineage differentiation in vitro. Finally, TET3 depletion renders AML cells highly sensitive to blockage of the TET3 downstream pathways glycolysis and STAT5 signaling via the combination of 2-Deoxy-D-glucose and STAT5 inhibitor which preferentially targets AML cells but spares healthy CD34+ HSPCs.

TET1 promotes growth of T-cell acute lymphoblastic leukemia and can be antagonized via PARP inhibition.

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological cancer characterized by skewed epigenetic patterns, raising the possibility of therapeutically targeting epigenetic factors in this disease. Here we report that among different cancer types, epigenetic factor TET1 is highly expressed in T-ALL and is crucial for human T-ALL cell growth in vivo. Knockout of TET1 in mice and knockdown in human T cell did not perturb normal T-cell proliferation, indicating that TET1 expression is dispensable for normal T-cell growth. The promotion of leukemic growth by TET1 was dependent on its catalytic property to maintain global 5-hydroxymethylcytosine (5hmC) marks, thereby regulate cell cycle, DNA repair genes, and T-ALL associated oncogenes. Furthermore, overexpression of the Tet1-catalytic domain was sufficient to augment global 5hmC levels and leukemic growth of T-ALL cells in vivo. We demonstrate that PARP enzymes, which are highly expressed in T-ALL patients, participate in establishing H3K4me3 marks at the TET1 promoter and that PARP1 interacts with the TET1 protein. Importantly, the growth related role of TET1 in T-ALL could be antagonized by the clinically approved PARP inhibitor Olaparib, which abrogated TET1 expression, induced loss of 5hmC marks, and antagonized leukemic growth of T-ALL cells, opening a therapeutic avenue for this disease.

[µ-1,3-Bis(diphenyl-phosphino)propane-κP:P']bis-[bromidogold(I)].

The title compound, [Au(2)Br(2)(C(27)H(26)P(2))], features linearly coordinated Au(I) atoms within P,Br-donor sets. The central portion of the mol-ecule is practically planar as quanti-fied by the Br-Au⋯Au-Br torsion angle of -169.9 (2)°. The P-Au-Br chromophores are twisted with respect to each other [dihedral angle = 52.3 (6)°]. The benzene rings on each P atom lie on either side of this plane. The Au atoms are positioned at the periphery of the mol-ecule, which facilitates the formation of Au⋯Au inter-actions [3.2575 (11) Å] that result in the formation of supra-molecular chains along the b-axis direction. The Au⋯Au inter-actions are responsible for the deviations from the ideal linear geometry for each Au atom.

[µ-1,1'-Bis(diphenyl-phosphino)ferro-cene-κP:P']bis-[chloridogold(I)]-chloro-form-hexane (2/2/1).

In the title mixed solvate, [Au(2)Fe(C(17)H(14)P)(2)Cl(2)]·CHCl(3)·0.5CH(3)(CH(2))(4)CH(3), the hexane solvent mol-ecule is disposed about an inversion centre. The Au atoms exist within nearly ideal linear coordination defined by P,Cl-donor sets, and when viewed down the P⋯P axis the Au atoms are gauche to each other. In the crystal structure, the chloro-form solvent mol-ecule is associated with the complex via a C-H⋯Cl contact, and the hexane solvent mol-ecules occupy voids defined by the remaining components of the structure.

Efficient and reproducible depletion of hepatitis B virus from plasma derived extracellular vesicles.

Extracellular vesicles (EVs) are emerging fundamental players in viral infections by shuttling viral components, mediating immune responses and likely the spread of the virus. However, the obstacles involved in purifying EVs and removing contaminating viral particles in a reliable and effective manner bottlenecks the full potential for the development of clinical and diagnostic treatment options targeting EV. Because of the similarities in size, density, membrane composition and mode of biogenesis of EVs and virions there are no standardized approaches for virus-removal from EV preparations yet. Functional EV studies also require EV samples that are devoid of antibody contaminants. Consequently, the study of EVs in virology needs reliable and effective protocols to purify EVs and remove contaminating antibodies and viral particles. Here, we established a protocol for EV purification from hepatitis B virus (HBV)-containing plasma by a combination of size-exclusion chromatography and affinity-based purification. After purification, EV samples were free of virus-sized particles, HBV surface antigen, HBV core antigen, antibodies or infectious material. Viral genomic contamination was also decreased following purification. By using appropriate antibodies and size parameters, this protocol could potentially be applied to purification of EVs from other viral samples. In summary, we established a fast, reproducible and robust approach for the removal of HBV from EV preparations. Looking forward to the point of purifying EVs from clinical samples, this method should enable studies shedding light on the underlying mechanisms of EVs in viral infections and their diagnostic and prognostic potential.

Reaction of 2-[(2-aminoethyl)amino]ethanol with pyridine-2-carbaldehyde and complexation of the products with CuII and CdII along with docking studies.

The reaction between 2-[2-(aminoethyl)amino]ethanol and pyridine-2-carbaldehyde in a 1:2 molar ratio affords a mixture containing 2-({2-[(pyridin-2-ylmethylidene)amino]ethyl}amino)ethanol (PMAE) and 2-[2-(pyridin-2-yl)oxazolidin-3-yl]-N-(pyridin-2-ylmethylidene)ethanamine (POPME). Treatment of this mixture with copper(II) chloride or cadmium(II) chloride gave trichlorido[(2-hydroxyethyl)({2-[(pyridin-2-ylmethylidene)amino]ethyl})azanium]copper(II) monohydrate, [Cu(C10H16N3O)Cl3]·H2O or [Cu(HPMAE)Cl3]·H2O, 1, and dichlorido{2-[2-(pyridin-2-yl)oxazolidin-3-yl]-N-(pyridin-2-ylmethylidene)ethanamine}cadmium(II), [CdCl2(C16H18N4O)] or [CdCl2(POPME)], 2, which were characterized by elemental analysis, FT-IR, Raman and 1H NMR spectroscopy and single-crystal X-ray diffraction. PMAE is potentially a tetradentate N3O-donor ligand but coordinates to copper here as an N2 donor. In the structure of 1, the geometry around the Cu atom is distorted square pyramidal. In 2, the Cd atom has a distorted octahedral geometry. In addition to the hydrogen bonds, there are π-π stacking interactions between the pyridine rings in the crystal packing of 1 and 2. The ability of PMAE, POPME and 1 to interact with ten selected biomolecules (BRAF kinase, CatB, DNA gyrase, HDAC7, rHA, RNR, TrxR, TS, Top II and B-DNA) was investigated by docking studies and compared with doxorubicin.

Synthesis, characterization, and in vitro cytotoxicity of some gold(I) and trans platinum(II) thionate complexes containing water-soluble PTA and DAPTA ligands. X-ray crystal structures of [Au(SC4H3N2)(PTA)], trans-[Pt(SC4H3N2)2(PTA)2], trans-[Pt(SC5H4N)2(PTA)2], and trans-[Pt(SC5H4N)2(DAPTA)2].

A series of gold(I) and platinum(II) complexes of the type [Au(SR)(P)] and trans-[Pt(SR) 2(P) 2] [SR = 2-thiopyridine (SPy), 2-thiopyrimidine (SPyrim); P = 1,3,5-triaza-7-phosphaadamantane (PTA), 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane (DAPTA)] were prepared and characterized, and their in vitro cytotoxicities against a panel of seven human cancer cell lines were evaluated. The highly water soluble gold(I) complexes [Au(SR)(P)] [P = PTA and SR = SPy ( 1), SPyrim ( 2); P = DAPTA and SR = SPy ( 3), SPyrim ( 4)] showed low cytotoxicity, while the platinum(II) complexes trans-[Pt(SR) 2(P) 2] [P = PTA and SR = SPyrim ( 5), SPy ( 6); P = DAPTA and SR = SPyrim ( 7), SPy ( 8)] demonstrated potent cytotoxicity for ovarian, colon, renal, and melanoma cancer cell lines on the basis of a comparison with ID 50 values for some established cytotoxic drugs. Single crystals of 2, 5, 6, and 8 suitable for X-ray structural characterization were obtained, and the study revealed the trans configuration for 5, 6, and 8 in their solid states.

Synthesis and Reactivity of 3,3-Diazidooxindoles.

The synthesis of previously unknown 3,3-diazidooxindoles as synthetically useful derivatives of isatins was accomplished through the direct oxidative diazidation of 2-oxindoles. The method yielded the diazido compounds from the starting oxindoles under mild and simple conditions with NaN3 and iodine, in good yields. The notable reactivity of this new class of compounds toward primary and secondary nucleophilic amines is also described, which gives access to either 4-imino-3,4-dihydroquinazolin-2(1 H)-one derivatives or cyanophenylureas.