Isolation of Bacillus stearothermophilus constituent that suppresses mouse mixed leukocyte reaction in vitro.

A novel immunosuppressant, Fr.5-B, has been isolated from the debris of Bacillus stearothermophilus UK563 autolysate. Fr.5-B suppressed mouse mixed leukocyte reaction at doses ranging from 10(-4) to 1 microgram/ml, but not proliferation stimulated by concanavalin A and lipopolysaccharide.     

Eta 1 and eta 2 Coordination of 1-amino-closo-dodecaborate

The reaction of the sodium salt of 1-amino-closo-dodecaborate [Na]2[NH2-B12H11] ([Na]2[1]) with [Au(PPh3)Cl] and [Ni(THF)2(Br)2] led to eta 1(N) coordination of 1in [Na][Au(PPh3)(NH2-B12H11)] (2) and [Na]6[Ni(NH2-B12H11)4] (3), respectively. Furthermore, eta 2(N,BH) coordination of was found in [MePPh3][Rh(PPh3)2(NH2-B12H11)] (4), which was synthesized by the reaction of [MePPh3][Na][1] with [Rh(PPh3)3Cl]. All compounds were characterized by single crystal X-ray diffraction and heteronuclear NMR spectroscopy.     

Synthesis and structures of selected benzamidinates of Li, Na, Al, Zr and Sn(II) using the C1-symmetric ligands [N(SiMe3)C(C6H4Me-4 or Ph)NPh]-

Several compounds based on the C(1)-symmetric ligands [N(R)C(Ar)NPh]- [abbreviated as B1 (Ar = C(6)H(4)Me-4) or B2 (Ar = Ph), R = SiMe(3)] are reported. They are the crystalline metal benzamidinates [Li(mu:kappa2-B1)(OEt2)](2) (1), [Al(kappa2-B1)2Me] (2), [Al(kappa2-B1)2X] [X = Cl/Me, 1 : 1 (3)], [Sn(kappa2-B1)2] (4), Zr(kappa2-B1)2Cl2 (5), [Zr(kappa2-B1)3Cl] (6), [Na(mu:kappa2-B1)(tmeda)]2 (7), K[B1] (8), Li(B2)(OEt2) (9) and Zr(kappa2-B1)3Cl (10) and the known benzamidine Z-H2NC(C6H4Me-4) = NPh (11). They were prepared by (i) insertion of the nitrile 4-MeC6H4CN (1, 7, 8, 11) or PhCN (9) into the appropriate M-N(R')Ph [R' = R and M = Li (1, 9), Na (7), K (8)] bond and subsequent hydrolysis for 11 [R' = H and M = Li], or (ii) a ligand transfer reaction using the lithium amidinate 1 and Al(Me)2Cl (2, 3), SnCl2 (4) or ZrCl4 (5, 6), or Li(B2) and ZrCl4 (10). The X-ray structures of 1, 2, 3, 4, 6b (i.e..3PhMe) 7, and 11 are presented. Exploratory polymerisation experiments are described, using 2, 5 or 6 as a procatalyst with methylaluminoxane (MAO) (Al : Zr ca. 500 : 1) as promoter. Thus toluene solutions were exposed to C2H4 under ambient conditions; while 2 was unresponsive, 5 and 6 showed modest activity in the formation of polyethylene.     

硼氢二茂铁季铵盐的结构化学研究——Ⅰ、十硼十氢双(二茂铁甲基三甲基)铵晶体结构

本文报告了(C_5H_5FeC_5H_4CH_2N(CH_3)_3)_2B_(10)H_(10)晶体的结构。该晶体属三斜晶系、空间群为P_1~-。晶胞参数为:a=10.043(2),b=10.513(7),C=15.094(10),a=85.01(6),β=97.58(3),Υ=94.87(3)°,V=1625.7~3,Z=2。晶体在室温下用CAD-4四圆衍射仪收集衍射强度数据(MoKa),用重原子法解出铁原子坐标,综合应用E图、Fourief合成和差Fourier合成解出其他非氢原子坐标,按SDP加氢程序等求解阳离子中40个氢原子位置。各原子坐标及热振动参数经全矩阵最小二乘方修正,对于2258个独立衍射点(I≥3σI)],偏离因子R=0.043。 结构分析表明,B_(10)H_(10)~(2+)阴离子和C_5H_5FeC_5H_4CH_2N(CH_3)_3~+阳离子分别按畸变的八面体和畸变的三角形配位。两个二茂铁季铵阳离子中,两对戊二稀环平面间距为3.271(5)。阳离子中主要键长平均值为:Fe-C=2.026,C—C(环)=1.401,C—N=1.503。B_(10)H_(10)~(2+)阴离子为四方(三角)十六面体笼状结构,主要键长平均值为:B—B(顶点到正方形平面原子)1.706A,B—B(其它原子间)=1.830。     

Synthesis, characterization and optical properties of pi-conjugated systems incorporating closo-dodecaborate clusters: new potential candidates for two-photon absorption processes

Non-centrosymmetric pi-conjugated systems incorporating closo-dodecaborate clusters, [NC-C6H4-C(H=N(H)-B12H11]-(2), [NC-C6H4-C(H)=C(H)-C(6)H(4)-C(H)=N(H)-B12H11]-(3), and [NC-C6H4-C(H)=C(H)-C6H4-C(H)=C(H)-C6H4-C(H)=N(H)-B12H11]-(4) have been synthesized by reaction of the monoamino derivative of B12, [B12H11NH3]-(1), with various arylaldehydes, R-C6H4-CHO. These Schiff base-like compounds were fully characterized by multinuclear NMR spectroscopy and mass spectrometry. In order to evaluate these boron rich pi-systems as potential materials for two-photon absorption (TPA) processes, UV linear absorption curves were recorded for 3 and 4, and comparatively studied with those of the boron-free pi-systems NC-C6H4-C(H)=N-CH3(5) and NC-C6H4-C(H)=C(H)-C6H4-C(H)=N-CH3(6). The donor effect of the boron cluster was evidenced by a shift to the lower energy of the absorption band in the spectra of systems incorporating B12. The two photon absorption (TPA) spectrum of compound , obtained by the up-conversion method, shows a resonance at 720 nm with a cross-section sigma(TPA) of 35 x 10(-50) cm(4) s photon(-1) molecule(-1). This value suggests the potential of B12 clusters to be used as new donor groups for the synthesis of non-linear materials.     

Synthesis and Crystal Structure of [(PPh3)(CH3COS)2NiB10H10]·0.4(C5H12)

The title compound [(PPh3)(CH3COS)2NiB10H10]·0.4(C5H12) has been synthesized by the reaction of [NiCl2(PPh3)2], closo-[B10H10]2- and CH3COSH in CH2Cl2 solution. It was recrystallized from n-pentane/CH2Cl2 solution and its structure was determined by X-ray diffraction analysis. The crystal is triclinic, space group P1, Mr=618.23, with a=10.049(1), b=12.638(2), c=14.077(2) , α=110.13(1), β=87.65(1), γ=96.01(1)°, V=1669.3(4)(A)3, Dc=1.230 g/cm3, Z=2, λ(MoKα)=0.71073(A), μ=7.76 cm-1, F(000)=642. The final refinement is converged with R=0.042 (5986 observed reflections with I≥2σ(I)), wR2 =0.151. The cluster is a nido eleven-vertex {NiB10} cage with the Ni atom in the open NiB4 face. Cyclizations resulting in two five-membered rings, Ni(7)-S(1)-C(1)-O(1)-B(2) and Ni(7)-S(2)-C(2)-O(2)-B(3), have occurred.     

Immunomodulatory constituents from an ascomycete, Microascus tardifaciens.

Fractionation guided by the immunosuppressive activity of the defatted AcOEt extract of an Ascomycete, Microascus tardifaciens, afforded eight constituents, questin (emodin 8-O-methylether) (1), rubrocristin (2), 5,7-dihydroxy-4-methylphthalide (3), cladosporin (asperentin) (4), cladosporin 8-O-methylether (5), tradioxopiperazine A [cyclo-L-alanyl-5-isopentenyl-2-(1',1'-dimethylallyl)-L-tryptophan] (6), tradioxopiperazine B [cyclo-L-alanyl-7-isopentenyl-2-(1',1'-dimethylallyl)-L-tryptophan] (7), and asperflavin (8), among which 6 and 7 were new compounds. Compounds 1 and 2 showed considerably high immunosuppressive activity, 6 was moderate and, 3, 4, 5, 7 and 8 showed low activity.     

[B20H18]n-(n=0,2,4,6)离子异构体的结构、稳定性与电子计数规则

对单个多面体硼烷(Polyhedral boranes)已有较多的理论研究，由多个多面体通过共用一个或多个顶点而构成的稠合型硼烷(Macropolyhedral borones)，具有多种多样的结构类型，并已被大量合成出来，目前对稠合型硼烷结构及成键特性的理论研究尚不充分，它们不能再以简单的closo，nido和arachno分类，Wade规则也不再适于解释其结构，理论上各种电子计数规则已有不少报道，对预言和发现新的分子十分重要。     

Complex [Ag(PPh3)4][2-B10H9NH3 · 2DMF]: Synthesis and Structure

Russian Journal of Coordination Chemistry - The formation of complex salt [Ag(PPh3)4][2-B10H9NH3 ? 2DMF] (I) by the reaction of the salts of the [2-B10H9NH3]– anion with [Ag(PPh3)4]NO3...     

Transition-metal-promoted reactions of boron hydrides. 17. Titanium-catalyzed decaborane-olefin hydroborations.

The titanium-catalyzed hydroboration reactions of decaborane with a variety of terminal olefins have been found to result in the exclusive, high-yield formation of monosubstituted decaborane 6-R-B(10)H(13) products, arising from anti-Markovnikov addition of the cage B6-H to the olefin. The titanium-catalyzed reactions are slow, often less than one turnover per hour; however, their high selectivities and yields coupled with the fact that they are simple, one-pot reactions give them significant advantages over the previously reported routes to 6-R-B(10)H(13) compounds. The catalyst also has extended activity with reactions carried out for as long as 13 days, showing little decrease in reactivity, thereby allowing for the production of large amounts of 6-R-B(10)H(13). The titanium-catalyzed reactions of decaborane with the nonconjugated diolefins, 1,5-hexadiene and diallylsilane, were found to give, depending upon reaction conditions and stoichiometries, high yields of either alkenyl-substituted 6-(CH(2)=CH(CH(2))(4))-B(10)H(13) (4) and 6-(CH(2)=CHCH(2)SiMe(2)(CH(2))(3))-B(10)H(13) (5) or linked-cage 6,6'-(CH(2))(6)-(B(10)H(13))(2) (6) and Me(2)Si(6-(CH(2))(3)-B(10)H(13))(2) (7) compounds, respectively. The unique tetra-cage product, Si(6-(CH(2))(3)-B(10)H(13))(4) (8), was obtained by the catalyzed reaction of 4 equiv of decaborane with tetraallylsilane. Sequential use of the titanium catalyst and previously reported platinum catalysts (PtBr(2) or H(2)PtCl(6).6H(2)O with an initiator) provides an efficient pathway to asymmetrically substituted 6-R-9-R'-B(10)H(12) species. The structures of compounds 5, 6, and 8, as well as a platinum derivative, (PSH(+))(2)-commo-Pt-[nido-7-Pt-8-(n-C(8)H(17))B(10)H(11)](2)(2-), of 6-(n-octyl)decaborane have been established by single-crystal crystallographic determinations.     

Automated method to estimate catecholamine and indoleamine content and turnover rates

A double-label isotopic method for estimation of the rate of formation of serotonin (5-HT) and dopamine (DA) in mouse striatum, hippocampus and cortex was standardized. Mice received an intravenous pulse injection of [3H]tryptophan (TRP) and [3H]tyrosine (TYR) at 2.5, 5, 10 or 20 min before sacrifice by microwave irradiation. Compounds of interest were separated by automated high-performance liquid chromatography and their contents were determined by electrochemical detection. Programmed collection of the TYR, DA, 5-HT and TRP peaks allowed determination of their radioactivity by liquid scintillation. Conversion of [3H]TYR to [3H]DA was nearly ten times greater in striatum than cortex, whereas the formation of [3H]5-HT from [3H]TRP was similar in striatum, cortex and hippocampus.     

Cationic Re(V) oxo complexes with poly(pyrazolyl)borates: synthesis, characterization, and stability

Cationic Re(V) oxo compounds of the type [ReO(OSiMe3)(eta 2-B(pz)4)(L)2]X [X = Cl, L = 4-(NMe2)C5H4N (1), 1-Meimz (1-methylimidazole; 2), 1/2 dmpe (1,2-bis(dimethylphosphino)ethane; 3), py (4a); X = I, L = py (4b)] can be prepared by reacting trans-[ReO2(eta 2-B(pz)4)(L)2] with XSiMe3. In solution, cations 1-4 are reactive species, and those with unidentate nitrogen donor ligands (1, 2, and 4) rearrange into the neutral derivatives [ReO(Cl)(OSiMe3)(eta 2-B(pz)4)(L)] [L = py (5), 4-(NMe2)C5H4N (6), 1-Meimz (7)], which are also reported herein. Compounds 1-3 and 5-7 have been fully characterized by the usual spectroscopic techniques, which in some cases includes X-ray crystallographic analysis (3, 6, and 7). Compound 3 crystallizes from CH2Cl2/n-hexane as yellow crystals with one molecule of CH2Cl2 solvent, and compounds 6 and 7 crystallize from THF/n-hexane as violet and red crystals, respectively, with one molecule of THF solvent in the case of 6. Crystallographic data: 3, orthorhombic space group Pn2(1)a, a = 11.311(2) A, b = 19.135(2) A, c = 15.443(2) A, V = 3342.4(8) A3, Z = 4; 6, triclinic space group P1, a = 8.7179(11) A, b = 12.5724(8) A, c = 17.750(2) A, alpha = 70.454(7) degrees, beta = 77.935(9) degrees, gamma = 77.129(8) degrees, V = 1768.1(3) A3, Z = 2; 7, monoclinic space group P2(1)/c, a = 16.356(2) A, b = 20.384(3) A, c = 17.360(3) A, beta = 106.971(12) degrees, V = 5535.8(14) A3, Z = 8.     

Synthesis,Crystal Structure and Antitumor Activity in Vitro of a New Benzoate Binuclear Cupper（ Ⅱ） Complex

The title compound, [Cu2（C7H5O2）4（C2H6O）2], was synthesized by the reaction of benzoic acid, copper acetate and ethanol in an aqueous solution. Trypan blue dye exclusion method was used in experiment. X-ray single-crystal analysis has revealed that compound 1 （C32H32Cu2O10） crystallizes in the monoclinic system, space group C2/c, Mr = 703.66, a = 47.340（5）, b = 6.6613（4）, c = 22.028（2）A,β = 113.284（4）°, V = 6380.6（10） A^3, Z = 8, Dc= 1.465 g/cm^3, F（000） = 2896,μ = 1.388 mm^-11, the final R = 0.0515 and wR = 0.1172 for 5712 observed reflections with I 〉 2σ（I）. X-ray crystal structure analysis suggests that compound [CH2（C7H5O2）4（C2H6O）2] has a binuclear structure with two Cu（II） atoms coordinated by four benzoate groups and two ethanol molecules. The crystal packing is stabilized by intermolecular O-H...O hydrogen bonds. The compound inhibits the proliferation of K562 cells （chronic myeloid leukemic cells） significantly and dose-dependently in 48 h, and IC50 of K562 is 17.3μg/mL by trypan blue dye exclusion method.     

Metabolic fates of L-tryptophan in Saccharomyces uvarum (Saccharomyces carlsbergensis).

The metabolism of L-tryptophan by Saccharomyces uvarum (carlsbergensis) was investigated by simultaneous measuring of fluxes through kynureninase, through transaminases and into protein using L-[methylene-14C] and L-[side chain-2,3-3H]tryptophan. In yeasts cultivated in synthetic medium (S medium), the flux into protein was predominant, closely followed by the flux leading to 2-3H liberation. The proportion of L-tryptophan metabolized via the latter flux increased over 10-fold (75% of total tryptophan metabolized) as the concentration of L-tryptophan was raised from 5 x 10(-5) to 5 x 10(-4) M. L-Tryptophan metabolized via the kynureninase flux was less than 5% of total tryptophan metabolized. In yeast extract-polypepton-glucose medium (YPG medium), more tryptophan was incorporated into protein than in the S medium. Contribution of the kynureninase flux remained very low. Tryptophan metabolism via each flux changed depending on the growth phase. 2-3H liberation was shown to be primarily due to tryptophol synthesis by high performance liquid chromatography (HPLC) and nuclear magnetic resonance (NMR), indole-3-acetic acid and kynurenic acid also contributing to 2-3H liberation but to a much lesser extent. 2-3H liberation increased dose-dependently at tryptophan concentration higher than 10(-5)M, while the kynureninase flux reached its plateau at 10(-5)M. Formation of tryptophol and indole-3-acetic acid via indole-3-pyruvic acid and indole-3-acetaldehyde with indole aldehyde as a by-product was confirmed using exogenous tryptophan metabolites with indole rings.     

PTP1B Inhibitory Secondary Metabolites from an Antarctic Fungal Strain Acremonium sp. SF-7394

Chemical investigation of the Antarctic lichen-derived fungal strain Acremonium sp. SF-7394 yielded a new amphilectane-type diterpene, acrepseudoterin (1), and a new acorane-type sesquiterpene glycoside, isocordycepoloside A (2). In addition, three known fungal metabolites, (−)-ternatin (3), [D-Leu]-ternatin (4), and pseurotin A (5), were isolated from the EtOAc extract of the fungal strain. Their structures were mainly elucidated by analyzing their NMR and MS data. The absolute configuration of 1 was proposed by electronic circular dichroism calculations, and the absolute configuration of the sugar unit in 2 was determined by a chemical method. The inhibitory effects of the isolated compounds on protein tyrosine phosphatase 1B (PTP1B) were evaluated by enzymatic assays; results indicated that acrepseudoterin (1) and [D-Leu]-ternatin (4) dose-dependently inhibited the enzyme activity with IC₅₀ values of 22.8 ± 1.1 μM and 14.8 ± 0.3 μM, respectively. Moreover, compound 1 was identified as a competitive inhibitor of PTP1B.     

Relative stabilities of weakly coordinating anions: a computational study

This article describes BP86/SV(P) (DFT) calculations on a representative set of weakly coordinating anions (WCAs) of type [M(L)n]-, their parent neutral Lewis acids M(L)(n-1) and their ate complexes with fluoride, that is, [FM(L)(n)](n-1) (M=B, L=F, OTeF5, C6H5, C6F5, C6H3(CF3)2, CF3; M=P, As, Sb, L=F, OTeF5; M=Al, L=OC(CF3)3). Compounds with fluoride bridges, that is, Sb(n)F(5n) and [Sb(n)F(5n+1)]- (n=2, 3, 4), Al2(L)5F and [(L)3Al-F-Al(L)3]- (L=OC(CF3)3), (F4C6[1,2-B(L)2]2, [F4C6[1,2-B(L)2]2F]-, [F4C6[1,2-B(L)2]2OMe]- (L=C6F5) were also calculated. Based on these BP86/SV(P) and auxiliary MP2/TZVPP, G2, and CBS-Q calculations the relative stabilities and coordinating abilities of these WCAs were established with regard to the fluoride ion affinities (FIA) of the parent Lewis acids, the ligand affinity (LA) of the WCAs, the decomposition of a given WCA in the presence of a hard (H+, proton decomposition PD) and a soft electrophile (Cu+, copper decomposition CuD), the position of the HOMO, the HOMO-LUMO gap, and population analyses of the anions providing partial charges for all atoms. To obtain data that is more reliable, the assessed quantities were calculated through isodesmic reactions. If parts of the calculations could not be done isodesmically, higher levels such as MP2/TZVPP, G2, and CBS-Q were used to obtain reliable values for these reactions. Although the obtained results can not be taken as absolute, the relative ordering of the stabilities of all WCAs will undoubtedly be correct, since a single methodology was chosen for the investigation. To include media effects the decomposition reactions of a subset of 14 WCAs with the SiMe3+ and [Cp2ZrMe]+ ions were also calculated in PhCl and 1,2-F2C6H4 (COSMO solvation model). We found that in most cases gas-phase calculations and solution calculations give comparable results for the stability of the anion. Applications of the LA and FIA that allow one to decide, on thermodynamic grounds, which WCA or Lewis acid is the most suitable for a given problem are sketched.     

Central nervous system antigen (NS-5) and its presence during murine ontogenesis.

An antiserum raised by immunization of C3H.SW/Sn mice with cerebellum from 4-day-old C57BL/6J mice recognizes a cell surface component(s) [NS-5] present in different degrees on various parts of the mouse central nervous system. When analyzed by an antiserum- and complement-mediated cell cytotoxicity test and by the ability of various tissuesto absorb anti-NS-5 antiserum activity, the antigen(s) was detectable on cerebellum, retina, olfactory bulb, cortex, basal ganglia, and medulla but not on nonneural tissues with the exception of mature spermatozoa and 4-day-old kidney. The antigen(s) detected by the anti-NS-5 antiserum was found in similar quantities on young and adult rat and mouse cerebellum; however, it was not detectable on any of 16 clonal cell lines derived from the rat central nervous system. During preimplantation stages of murine development, the antigen could be detected on all cells of (2-4)-cell and (8-16)-cell stages and on the trophoblastic cells of blastocysts by indirect immunofluorescence, Embryos on day 9 of gestation, the earliest tested after implantation, expressed the antigen(s), but expression was restricted to the nervous system.     

Hydrogen-bonded 1D and 2D Assemblies of Tetraiso-butyl-resorcin[4]arene in the Crystalline State

1 INTRODUCTION There is continuing interest in the assembly of molecular capsules based on concomitant formation of multiple hydrogen bonds between smaller mole- cular components[1]. A particularly attractive buil- ding block is calix[4]resorcinarenes with eight pen- dant hydroxyl functional groups[2]. In a crystal engi- neering design strategy for molecular self-assembly, cocrystallization of C-methylcalix[4]resorcinarenes with nitrogen-donor molecules such as pyridines in the presence …     

A computational investigation of the geometrical structure and protodeboronation of boroglycine, H2N-CH2-B(OH)2

In this article the geometrical structure of the simple, achiral, alpha-amino boronic acid boroglycine, H2N-CH2-B(OH)2, was investigated using density functional theory (DFT), second-order M?ller-Plesset (MP2) perturbation theory, and coupled cluster methodology with single- and double-excitations (CCSD); the effects of an aqueous environment were incorporated into the results by using a few explicit water molecules and/or self-consistent reaction field (SCRF) calculations with the IEF polarizable continuum model (PCM). Neutral reaction mechanisms were investigated for the direct protodeboronation (hydrolysis) of boroglycine (H2O+H2N-CH2-B(OH)2-->B(OH)3+H2N-CH3), for which DeltaH degrees 298 was -21.9 kcal/mol at the MP2(FC)/aug-cc-pVDZ level, and for the 1,2-carbon-to-nitrogen shift of the -B(OH)2 moiety (H2N-CH2-B(OH)2-->H3C-NH-B(OH)2), for which the corresponding value of DeltaH degrees 298 was -18.2 kcal/mol. A boron-oxygen double-bonded intermediate was found to play an important role in the 1,2-rearrangement mechanism.