Biotransformation of a C-glycosylflavone, abrusin 2''-O-beta-D-apioside, by human intestinal bacteria

After anaerobic incubation of abrusin 2'-O-beta-D-apioside (1) with a human fecal suspension, five metabolites were isolated and identified as abrusin (2), 1-(2',6'-dihydroxy-3',4'-dimethoxyphenyl)-3-(4'-hydroxyphenyl)propan-1- one (5), 5,6-dimethoxybenzene-1,3-diol (6), 3-(4'-hydroxyphenyl)propionic acid (7) and 3-phenylpropionic acid (8). However, methyl ether derivatives of abrusin (4'-O-methylabrusin and 4'-O-, 5-O-dimethylabrusin) resisted degradation under the same conditions.     

Al and Zn complexes bearing N,N,N-tridentate quinolinyl anilido-imine ligands: synthesis, characterization and catalysis in l-lactide polymerization

Reactions of N,N,N-tridentate quinolinyl anilido-imine ligands with AlMe(3) afford mononuclear aluminum complexes {κ(3)-[{2-[ArN[double bond, length as m-dash]C(H)]C(6)H(4)}N(8-C(9)H(6)N)]}AlMe(2) (Ar = 2,6-Me(2)C(6)H(3) (1a), 2,6-Et(2)C(6)H(3) (1b), 2,6-(i)Pr(2)C(6)H(3) (1c)) or dinuclear complexes AlMe(3){κ(1)-[{2-[ArN[double bond, length as m-dash]C(H)C(6)H(4)]N(8-C(9)H(6)N)}-κ(2)]AlMe(2) (R = 2,6-Me(2)C(6)H(3) (2a), 2,6-Et(2)C(6)H(3) (2b), 2,6-(i)Pr(2)C(6)H(3) (2c)) depending on the ratios of reactants used. Similar reactions of ZnEt(2) with these ligands give the monoligated ethyl zinc complexes {κ(3)-[{2-[ArN[double bond, length as m-dash]C(H)]C(6)H(4)}N(8-C(9)H(6)N)]}ZnEt (Ar = 2,6-Me(2)C(6)H(3) (3a), 2,6-Et(2)C(6)H(3) (3b), 2,6-(i)Pr(2)C(6)H(3) (3c)) or bisligated complexes {κ(3)-[{2-[ArN[double bond, length as m-dash]C(H)]C(6)H(4)}N(8-C(9)H(6)N)]}Zn{κ(2)-[{2-[ArN[double bond, length as m-dash]C(H)]C(6)H(4)}N(8-C(9)H(6)N)]} (Ar = 2,6-Me(2)C(6)H(3) (4a), 2,6-Et(2)C(6)H(3) (4b), 2,6-(i)Pr(2)C(6)H(3) (4c)). These complexes were well characterized by NMR and the structures of 1a, 2a, 2c, 3b and 4c were confirmed by X-ray diffraction analysis. The aluminum and zinc complexes were tested to initiate lactide polymerization in which the zinc complexes show moderate to high activities in the presence of benzyl alcohol.     

Synthesis,Properties, Structure and Reactivity of Sodium 2,3,4,5-Tetra- tert -butylcyclopentaphosphanide

The reaction between Na, t BuPCl 2 , and PCl 3 in thf gives Na[ cyclo -( t Bu 4 P 5 )] ( 1 ). 1 reacts with PCl 3 to yield ( cyclo - t Bu 3 P 4 ) t BuPCl ( 2 ), and with a proton source, such as HCl, NH 4 Cl, or t BuCl, to give cyclo - t Bu 4 P 5 H ( 3 ). The reaction of 1 with [MCl 2 (PRR' 2 ) 2 ] (M = Ni; R = R' = Et; M = Pd, Pt, R = Ph, R' = Me) gives [Ni{ cyclo -( t Bu 3 P 5 )}(PEt 3 ) 2 ] ( 4 ), [Pd{ cyclo -( t Bu 4 P 5 )} 2 ] ( 5 ), and [PtCl{ cyclo -( t Bu 3 P 4 ) t BuP}(PPhMe 2 )] ( 6 ). 1-6 were characterized by 31 P{ 1 H} NMR spectroscopy, and 1 and 4-6 were also characterized by X-ray crystallography.     

Homoleptic trimethylsilylacetylide complexes of chromium(III), iron(II), and cobalt(III): syntheses, structures, and ligand field parameters

A straightforward method for synthesizing soluble homoleptic trimethylsilylacetylide complexes of first-row transition metal ions is presented. Reaction of anhydrous CrCl2 with an excess of LiCCSiMe3 in THF at -25 degrees C affords orange Li3[Cr(CCSiMe3)6].6THF (1), while analogous reactions employing M(CF3SO3)2 (M = Fe or Co) generate pale yellow Li4[Fe(CCSiMe3)6].4LiCCSiMe3.4Et2O (2) and colorless Li3[Co(CCSiMe3)6].6THF (3). Slightly modified reaction conditions lead to Li8[Cr2O4(CCSiMe3)6].6LiCCSiMe3.4glyme (4), featuring a bis-mu-oxo-bridged binuclear complex, and Li3[Co(CCSiMe3)5(CCH)].LiCF3SO3.8THF (5). The crystal structures of 1-3 show the trimethylsilylacetylide complexes to display an octahedral coordination geometry, with M-C distances of 2.077(3), 1.917(7)-1.935(7), and 1.908(3) angstroms for M = Cr(III), Fe(II), and Co(III), respectively, and nearly linear M-C[triple bond]C angles. The UV-visible absorption spectrum of [Cr(CCSiMe3)6]3- in hexanes exhibits one spin-allowed d-d transition (4T2g <-- 4A1g) and three lower-energy spin-forbidden d-d transitions. The spectra of [Fe(CCSiMe3)6]4- and [Co(CCSiMe3)6]3- in acetonitrile display high-intensity charge-transfer bands, which obscure all d-d transitions except for the lowest-energy spin-allowed band (1T1g <-- 1A1g) of the latter complex. Time-dependent density functional theory (TD-DFT) calculations were employed as an aide in assigning the observed transitions. Taken together, the results are most consistent with the ligand field parameters delta(o) = 20,200 cm(-1) and B = 530 cm(-1) for [Cr(CCSiMe3)6]3-, delta(o) = 32 450 cm(-1) and B = 460 cm(-1) for [Fe(CCSiMe3)6]4- and delta(o) = 32 500 cm(-1) and B = 516 cm(-1) for [Co(CCSiMe3)6]3-. Ground-state DFT calculations support the conclusion that trimethylsilylacetylide acts as a pi-donor ligand.     

2-[2-(4, 6-二甲基)-嘧啶基]-4-苯基-1, 2, 4-恶二唑烷-3, 5-二酮的合成

异氰酸苯酯和N-[2-(4, 6-二甲基)-嘧啶基]-羟胺(5)反应生成1-[2-(4, 6-二甲基)-嘧啶基]-1-羟基-3-苯基脲(6)。化合物(6)在三乙胺存在下和氯甲酸乙酯反应生成2-[2-(4, 6-二甲基)-嘧啶基]-4-苯基-1, 2, 4-恶二唑烷-3, 5-二酮(1)。     

Studies on the constituents of Broussonetia species VIII. Four new pyrrolidine alkaloids, broussonetines R, S, T, and V and a new pyrroline alkaloid, broussonetine U, from Broussonetia kazinoki Sieb

Four new pyrrolidine alkaloids, broussonetines R, S, T, and V and a new pyrroline alkaloid, broussonetine U were isolated from the branches of Broussonetia kazinoki SIEB. (Moraceae) in low yield. Broussonetines R, S and T were formulated as (2R,3R,4R,5R)-2-hydroxymethyl-3,4-dihydroxy-5-[(1R)-1-hydroxy-3-[6-(4-hydroxybutyl)-cyclohexy-2-on-1(6)-enyllpropyl] pyrrolidine (1), (2R,3R,4R,5R)-2-hydroxymethyl-3,4-dihydroxy-5-[(1R,10S)-1,10,13-trihydroxytridecyl] pyrrolidine (2), (2R,3R,4R,5R)-2-hydroxymethyl-3,4-dihydroxy-5-[(1R,5S)-1,5, 13-trihydroxy-10-oxo-tridecyl] pyrrolidine (3). And broussonetines U and V were proposed to be (2S,3S,4S)-2-hydroxymethyl-3, 4-dihydroxy-5-(9-oxo-13-hydroxytridecyl)-5-pyrroline (4), (2R,3S,4R,5R)-2-hydroxymethyl-3,4-dihydroxy-5-[(E)-9-oxo-13-hydroxy-3-tridecenyl] pyrrolidine (5), respectively, by spectroscopic and chemical methods.     

Syntheses, crystal and solution structures, ligand-exchange, and ligand-coupling reactions of mixed pentaarylantimony compounds

All possible combinations of mixed pentaarylantimony compounds bearing p-methylphenyl and p-trifluoromethylphenyl groups were synthesized; ArnTol5-nSb (n=0-5: Ar=p-CF3C6H4, Tol=p-CH3C6H4): Tol5Sb (1), ArTol4Sb (2), Ar2Tol3Sb (3), Ar3Tol2Sb (4), Ar4TolSb (5), and Ar5Sb (6). Compounds 2-5 are the first well-characterized examples of mixed acyclic pentaarylantimony species. The structures of 2-6 were determined by X-ray crystallography to feature trigonal-bipyramidal (TBP) geometry with the more electronegative p-trifluoromethylphenyl substituents selectively occupying the apical positions. Consideration of the chemical shifts of the ipso carbons of the aryl and tolyl groups suggested that the solution structures of 1-6 were also TBP, although their pseudorotation could not be frozen even at -80 degrees C. Ligand-exchange reactions (LERs) took place between 1 and 6 at approximately 60 degrees C in [D6]benzene and all six species 1-6 were found in the equilibrium mixture. The relative stabilities of 1-6 were determined quantitatively by comparison of the observed molar ratios of 1-6 in equilibrium with calculated statistical molar ratios, and Ar2Tol3Sb (3) was found to be the most stable. The ligand-coupling reactions (LCRs) of 2-5 in solution were greatly accelerated by adding Cu(acac)2 or Li+TFPB- (TFPB: [3,5-(CF3)2 C6H3]4 B), whereby the rate becomes comparable to the LER. The use of flash vacuum thermolysis (FVT) allowed the LCR to occur with very little ligand-exchange; the exception ArTol4Sb had very fast ligand-exchange. The selectivities of the LCRs were calculated from the yield of the biaryls synthesized by using FVT. These results were highly consistent with reactions catalyzed in solution, in which bitolyl was not obtained at all. The experimental results suggested that the LCR of pentaarylantimony compounds proceeds in the manner of apical-apical coupling.     

Rhodiolosides A-E, monoterpene glycosides from Rhodiola rosea

Five new monoterpene glycosides, rhodiolosides A-E (1-5), were isolated from the roots of Rhodiola rosea (Crassulaceae). Their structures were elucidated as (2E,6E,4R)-4,8-dihydroxy-3,7-dimethyl-2,6-octadienyl beta-D-glucopyranoside (1), (2E,4R)-4-hydroxy-3,7-dimethyl-2,6-octadienyl alpha-D-glucopyranosyl(1-->6)-beta-D-glucopyranoside (2), (2E,4R)-4-hydroxy-3,7-dimethyl-2,6-octadienyl beta-D-glucopyranosyl(1-->3)-beta-D-glucopyranoside (3), (2E,4R)-4,7-dihydroxy-3,7-dimethyl-2-octenyl beta-D-glucopyranoside (4), and (2E)-7-hydroxy-3,7-dimethyl-2-octenyl alpha-L-arabinopyranosyl(1-->6)-beta-D-glucopyranoside (5), on the basis of various spectroscopic analyses and chemical degradation.     

Human intestinal bacteria capable of transforming secoisolariciresinol diglucoside to mammalian lignans, enterodiol and enterolactone

Seven metabolites were isolated after anaerobic incubation of secoisolariciresinol diglucoside (1) with a human fecal suspension. They were identified as (-)-secoisolariciresinol (2), 3-demethyl-(-)-secoisolariciresinol (3), 2-(3-hydroxybenzyl)-3-(4-hydroxy-3-methoxybenzyl)butane-1,4-diol (4), didemethylsecoisolariciresinol (5), 2(3-hydroxybenzyl)-3-(3,4-dihydroxybenzyl)butane-1,4-diol (6), enterodiol (7) and enterolactone (8). Furthermore, two bacterial strains, Peptostreptococcus sp. SDG-1 and Eubacterium sp. SDG-2, responsible for the transformation of 1 to a mammalian lignan 7, were isolated from a human fecal suspension. The former transformed 2 to 3 and 5, as well as 4 to 6, and the latter transformed 5 to 6 and 7.     

Self-assembly, structures, and photophysical properties of 4,4'-bipyrazolate-linked metallo-macrocycles with dimetal clips

By employing functional diimine ligands coordinated dipalladium(II,II) or diplatinum(II,II) clips as corners and the coplanar 4,4'-bipyrazolate dianion (L(2-)) ligand as linker, a series of bipyrazolate-bridged metallo-macrocycles, namely, [M8L4](NO3)8 (M = Pd(dmbpy), 1; Pd(bpy), 2; Pt(bpy), 3a; Pd(phen), 4; Pt(phen), 5; Pd(15-crown-5-phen), 6; Pd(18-crown-6-phen), 8; Pd(benzo-24-crown-8-phen), 10a; Pt(15-crown-5-phen), 7a, Pt(18-crown-6-phen), 9a; Pt(benzo-24-crown-8-phen), 11a) and [M6L3](NO3)6 (M = Pt(bpy), 3b; Pt(15-crown-5-phen), 7b; Pt(18-crown-6-phen), 9b; Pd(benzo-24-crown-8-phen), 10b; Pt(benzo-24-crown-8-phen), 11b), have been synthesized through a directed self-assembly approach that involves spontaneous deprotonation of the 1H-bipyrazolyl ligands in aqueous solution. All these compounds have a crown-shaped cavity that can serve as host to solvent molecules and anions. The structures are characterized by elemental analysis, (1)H and (13)C NMR, ESI-MS, and in the cases of 1a (the BF4(-) salt of 1), 2a (the BF4(-) salt of 2), and 3b by single-crystal X-ray diffraction analysis. Photophysical properties for complexes 1 and 2 are discussed.     

Investigations on the stability of bendamustin, a cytostatic agent of the nitrogen mustard type, I. Synthesis, isolation, and characterization of reference substances

Summary The following compounds were chosen as reference substances for HPLC investigations on 4-(6-bis(2-chloro-ethyl)amino-3-methylbenzimidazoyl(2))butyric acid (bendamustin), an antineoplastic agent of the N-lost type (synthesized or isolated from crude bendamustin): 4-(6-((2-chloroethyl)(2-hydroxyethyl)amino)-3-methylbenzimidazoyl(2))butyric acid (HP1), 4-(6-bis(2-hydroxyethyl)amino-3-methylbenzimidazoyl(2))butyric acid (HP2), ethyl-4-(6-bis(2-hydroxyethyl)amino-3-methylbenzimidazoyl(2))butyrate (dihydroxyester), and ethyl-4-(6-bis(2-chloroethyl)amino-3-methylbenzimidazoyl(2))butyrate (dichloroester). Furthermore, the so far unidentified side product 4-(7,8-dihydro-6-(2-chloroethylamino)-3-methyl-1,4-thiazino[3,2-g]benzimidazoyl(2))-butyric acid (NP1), formed in the last step of the synthesis, was isolated and identified.

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Untersuchungen zur Stabilität von Bendamustin, einem Cytostatikum vom N-Lost-Typ, 1. Mitt.: Synthese, Isolierung und Charakterisierung von Vergleichssubstanzen

Zusammenfassung Die folgenden Verbindungen wurden als Vergleichssubstanzen für HPLC-analytische Untersuchungen von 4-(6-Bis(2-chlorethyl)amino-3-methylbenzimidazoyl(2))buttersäure (Bendamustin), einem Antitumormittel des N-lost-Typs, synthetisiert oder aus Bendamustin-Rohstoff vor der Endreinigung isoliert: (4-(6-((2-Chlorethyl)(2-hydroxyethyl)amino)-3-methylbenzimidazoyl(2))buttersäure (HP1), 4-(6-Bis(2-hydroxyethyl)amino-3-methylbenzimidazoyl(2))buttersäure (HP2), 4-(6-Bis(2-hydroxyethyl)amino-3-methylbenzimidazoyl(2))buttersäureethylester (Dichlorester). Weiterhin konnte das bislang unbekannte Nebenprodukt 4-(7,8-Dihydro-6-(2-chlorethylamino)-3-methyl-1,4-thiazino[3,2-g]benzimidazoyl(2))buttersäure (NP1), welches sich im letzten Schritt der Synthese bildet, isoliert und identifiziert werden.

     

Energetics of the O-H bond and of intramolecular hydrogen bonding in HOC6H4C(O)Y (Y = H, CH3, CH2CH=CH2, C[triple bond]CH, CH2F, NH2, NHCH3, NO2, OH, OCH3, OCN, CN, F, Cl, SH, and SCH3) compounds

The energetics of the phenolic O-H bond in a series of 2- and 4-HOC 6H 4C(O)Y (Y = H, CH3, CH 2CH=CH2, C[triple bond]CH, CH2F, NH2, NHCH 3, NO2, OH, OCH3, OCN, CN, F, Cl, SH, and SCH3) compounds and of the intramolecular O...H hydrogen bond in 2-HOC 6H 4C(O)Y, was investigated by using a combination of experimental and theoretical methods. The standard molar enthalpies of formation of 2-hydroxybenzaldehyde (2HBA), 4-hydroxybenzaldehyde (4HBA), 2'-hydroxyacetophenone (2HAP), 2-hydroxybenzamide (2HBM), and 4-hydroxybenzamide (4HBM), at 298.15 K, were determined by micro- or macrocombustion calorimetry. The corresponding enthalpies of vaporization or sublimation were also measured by Calvet drop-calorimetry and Knudsen effusion measurements. The combination of the obtained experimental data led to Delta f H m (o)(2HBA, g) = -238.3 +/- 2.5 kJ.mol (-1), DeltafHm(o)(4HBA, g) = -220.3 +/- 2.0 kJ.mol(-1), Delta f H m (o)(2HAP, g) = -291.8 +/- 2.1 kJ.mol(-1), DeltafHm(o)(2HBM, g) = -304.8 +/- 1.5 kJ.mol (-1), and DeltafHm(o) (4HBM, g) = -278.4 +/- 2.4 kJ.mol (-1). These values, were used to assess the predictions of the B3LYP/6-31G(d,p), B3LYP/6-311+G(d,p), B3LYP/aug-cc-pVDZ, B3P86/6-31G(d,p), B3P86/6-311+G(d,p), B3P86/aug-cc-pVDZ, and CBS-QB3 methods, for the enthalpies of a series of isodesmic gas phase reactions. In general, the CBS-QB3 method was able to reproduce the experimental enthalpies of reaction within their uncertainties. The B3LYP/6-311+G(d,p) method, with a slightly poorer accuracy than the CBS-QB3 approach, achieved the best performance of the tested DFT models. It was further used to analyze the trends of the intramolecular O...H hydrogen bond in 2-HOC 6H 4C(O)Y evaluated by the ortho-para method and to compare the energetics of the phenolic O-H bond in 2- and 4-HOC 6H 4C(O)Y compounds. It was concluded that the O-H bond "strength" is systematically larger for 2-hydroxybenzoyl than for the corresponding 4-hydroxybenzoyl isomers mainly due to the presence of the intramolecular O...H hydrogen bond in the 2-isomers. The observed differences are, however, significantly dependent on the nature of the substituent Y, in particular, when an intramolecular H-bond can be present in the radical obtained upon cleavage of the O-H bond.     

Synthesis, characterization, and photochromic properties of hybrid organic-inorganic materials based on molybdate, DABCO, and piperazine

Prompted by our interest in new photochromic organic-inorganic hybrid materials, the reactivity of [Mo7O24]6- toward a structure-directing reagent diamine such as 1,4-diazabicyclo[2.2.2]octane (DABCO) and piperazine (pipz) has been investigated, and three new molybdenum(VI)-containing compounds, namely, (H2DABCO)3[Mo7O24].4H2O (1), (H2DABCO)[Mo3O10].H2O (2), and (H2DABCO)2(NH4)2[Mo8O27].4H2O (3), have been synthesized and characterized. New synthetic routes to achieve the known compounds (H2DABCO)2(H2pipz)[Mo8O27] (4), (H2pipz)3[Mo8O27] (5), and (H2DABCO)2[Mo8O26].4H2O (6) are also reported. All of these compounds contain different poly(oxomolybdate) clusters, i.e., discrete [Mo7O24]6- blocks in 1, infinite polymeric chains 1/infinity[Mo3O10]2- in 2, 1/infinity[Mo8O27]6- in 3-5, and 1/infinity[Mo8O26]4- in 6, associated in a tridimensional assembly by hydrogen bonds with H2DABCO2+ and/or H2pipz2+ cations. Interconversion pathways and chemical factors affecting the stabilization of the different species are highlighted and discussed. At the opposite of 6, compounds 1-5 show photochromic behavior under UV excitation. Namely, compounds 1-5 shift from white or pale yellow to pale pink, reddish brown, or purple under UV illumination depending on the chemical nature of the mineral framework, with the kinetics of the color change being dictated by the nature of the organic component and by the organic-inorganic interface.     

Donor-Free Alkali Metal Thiolates: Synthesis and Structure of Dimeric, Trimeric, and Tetrameric Complexes with Sterically Encumbered Terphenyl Substituents

The synthesis and characterization of the tetrameric lithium thiolate (LiSC(6)H(2)-2,4,6-Ph(3))(4).C(7)H(8) (1), the trimeric lithium thiolate (LiSC(6)H(3)-2,6-Mes(2))(3).C(6)H(14)()()(2) (Mes = 2,4,6-Me(3)C(6)H(2)), the thiol HSC(6)H(3)-2,6-Trip(2) (3) (Trip = 2,4,6-i-Pr(3)C(6)H(2)), and the complete alkali metal series of dimeric thiolates (MSC(6)H(3)-2,6-Trip(2))(2) (M = Li (4, 5), Na (6), K (7), Rb (8), Cs (9)) are described. The compounds were characterized by (1)H, (7)Li, and (13)C NMR and IR spectroscopy and by X-ray crystallography. The compounds 1 and 2 crystallize as four- and three-rung ladder framework structures. The compounds 4-9 crystallize as dimers with M(2)S(2) cores. In addition, the metal ions interact with the ortho aryl groups to varying degrees in all the structures. The extent of these interactions appears to be determined mainly by ionic sizes and geometric factors. The coordination geometry of the thiolato sulfurs also varies from pyramidal in 1, 2, 4, 5, and 6 and one planar and one slightly pyramidal sulfur geometry in 7 to both sulfurs being planar coordinated in 8 and 9. Crystal data at 130 K are as follows: (LiSC(6)H(2)-2,4,6-Ph(3))(4).C(7)H(8) (1), a = 15.961(2) ?, b = 16.243(3) ?, c = 17.114(3) ?, alpha = 89.375(14) degrees, beta = 85.334(14) degrees, gamma = 63.343(12) degrees, V = 3950(1) ?(3), space group P&onemacr;, Z = 2, R(1) = 0.082; (LiSC(6)H(3)-2,6-Mes(2))(3).C(6)H(14)()()(2), a = 14.554(4) ?, b = 14.010(4) ?, c = 32.832(8) ?, beta = 95.20(2) degrees, V = 6667(2) ?(3), space group P2(1)/n, Z = 4, R(1) = 0.089; HSC(6)H(3)-2,6-Trip(2) (3), a = 8.180(2) ?, b = 25.437(5) ?, c = 15.752(3) ?, V = 3278(1) ?(3), space group Pnma, Z = 4, R(1) = 0.045; (LiC(6)H(3)-2,6-Trip(2))(2) (4), a = 12.652(2) ?, b = 14.218(1) ?, c = 18.713(2) ?, alpha = 83.56(1) degrees, beta = 84.36(1) degrees, gamma = 73.82(1) degrees, V = 3205(1) ?(3), space group P&onemacr;, Z = 2, R(1) = 0.055; (LiC(6)H(3)-2,6-Trip(2))(2).C(7)H(8) (5), a = 15.383(3) ?, b = 14.381(2) ?, c = 16.524(2) ?, beta = 111.10(1), V = 3410.3(9) ?(3), space group P2(1)/n, Z = 2, R(1) = 0.086; (NaSC(6)H(3)-2,6-Trip(2))(2).0.5C(7)H(8) (6), a = 13.952(2) ?, b = 20.267(2) ?, c = 24.475(3) ?, beta = 98.673(9) degrees, V = 6842(1) ?(3), space group P2(1)/n, Z = 4, R(1) = 0.068; (KSC(6)H(3)-2,6-Trip(2))(2).C(7)H(8) (7), a = 13.683(4) ?, b = 15.071(4) ?, c = 17.824(5) ?, alpha = 82.73(2), beta = 86.09(2), gamma = 88.46(2), V = 3637(2) ?(3), space group P&onemacr;, Z = 2, R(1) = 0.072; (RbSC(6)H(3)-2,6-Trip(2))(2).C(7)H(8) (8), a = 19.710(3) ?, b = 20.892(3) ?, c = 18.755(2) ?, beta = 106.900(9) degrees, V = 7389(2) ?(3), space group P2(1)/n, Z = 4, R(1) = 0.069; (CsSC(6)H(3)-2,6-Trip(2))(2) (9), a = 13.109(3) ?, b = 15.941(3) ?, c = 17.748(4) ?, alpha = 101.65(2) degrees, beta = 100.76(2) degrees, gamma = 104.25(2) degrees, V = 3410(1) ?(3), space group P&onemacr;, Z = 2, R(1) = 0.048.     

Simple, nitrogen-rich, energetic salts of 5-nitrotetrazole

A new family (ammonium, 1, hydrazinium, 2, guanidinium, 3, aminoguanidinium, 4, diamino-guanidinium, 5, and triaminoguanidinium, 6) of simple, nitrogen-rich energetic salts based on 5-nitro-2 H-tetrazole (HNT) were synthesized. In addition, the hemihydrate of 1 (1a) and the hydrate of 6 (6a) were also isolated. In all cases, stable salts were obtained and fully characterized by vibrational (IR, Raman) spectroscopy, multinuclear ((1)H, (13)C and (14)N) NMR spectroscopy, mass spectrometry, elemental analysis, and X-ray structure determination. Compounds 1and 2 crystallize in the monoclinic space group P2 1/c, 1a and 3 crystallize in C/2 c, 4 in P2 1/n, 5 in P2 1, 6 in orthorhombic P2 12 12 1, and 6a in triclinic P1. Initial safety testing (impact, friction, and electrostatic sensitivity) and thermal stability measurements (DSC) were also carried out. The NT salts all exhibit good thermal stabilities (decomposition above 150 degrees C). The constant volume energies of combustion (Delta c U(exp)) of 1-6 were experimentally determined by oxygen bomb calorimetry to be -1860(30) cal/g ( 1), -1770(30) cal/g ( 1a), -2110(150) cal/g (2), -2250(40) cal/g ( 3), -2470(30) cal/g (4), -2630(40) cal/g (5), -2690(50) cal/g (6), and -2520(50) cal/g (6a). Because of the significant experimental uncertainties obtained in these measurements, their validity was checked by way of quantum chemical calculation (MP2) of electronic energies and an approximation of lattice enthalpy. The predicted constant volume energies of combustion (Delta c U(pred)) calculated by this method were -2095.9 cal/g (1), -1975.7 cal/g ( 1a), -2362.4 cal/g (2), -2526.6 cal/g (3), -2654.6 cal/g (4), -2778.6 cal/g ( 5), -2924.0 cal/g (6), and -2741.4 cal/g ( 6a). From the experimentally determined density, chemical composition, and energies of formation (back calculated from the heats of combustion) the detonation pressures and velocities of 1 (7950 m/s, 23.9 GPa), 1a (7740 m/s, 22.5 GPa), 2(8750 m/s, 30.1 GPa), 3 (7500 m/s, 20.1 GPa) 4(8190 m/s, 24.7 GPa), 5(8230 m/s, 24.4 GPa), 6 (8480 m/s, 26.0 GPa) and 6a (7680 m/s, 20.7 GPa) were predicted using the EXPLO5 code.     

Synthesis, characterization, and reactivity of [Li(N6,N9-Me2Ade(-H))]: a structurally characterized lithiated adenine

The reaction of N6,N9-dimethyladenine (N6,N9-Me2Ade, 1) with methyllithium in aprotic solvents such as tetrahydrofuran and pyridine resulted in the formation of the lithiated adenine [Li(N6,N9-Me2Ade-H)] (2) that was isolated as highly air and moisture sensitive tetrahydrofuran (2.(1/4)THF) and pyridine (2.py) adducts in excellent yields (>90%). The identities of 2.(1/4)THF and 2.py were confirmed by 1H and 13C NMR spectroscopy. In crystals of 2.(3/2)py, the dimethyladeninato ligand exhibited a chelating and bridging coordination mode (kappa2N6,N7:kappaN3) resulting in a 1-D polymeric chain-like structure in which the tetrahedral coordination sphere of the lithium atoms was completed by a pyridine molecule. Reactions of 2.(1/4)THF with electrophiles such as MeI, Me3SiCl, and Me3SnCl resulted in high yields (88-98%) of the formation of the adenine deriatives N6,N6,N9-Me3Ade-H (3), N6-(SiMe3)-N6,N9-Me2Ade(-H) (4), and N6-(SnMe3)-N6,N9-Me2Ade-H (5), respectively. Compounds 3-5 were characterized by 1H, 13C, 29Si (4), and 119Sn (5) NMR spectroscopy and MS investigations, and the stannylated derivative 5 also was characterized by single-crystal diffraction analysis exhibiting a mononuclear structure. The reaction of the stannylated adenine 5 with n-BuLi in n-hexane proceeded in the sense of a tin-lithium transmetalation reaction yielding the solvent-free lithium adeninate [Li(N6,N9-Me2Ade-H)] (2) in 90% yield.     

Catalytic oxidation of 3,5-Di-tert-butylcatechol by a series of mononuclear manganese complexes: synthesis, structure, and kinetic investigation

The manganese compounds [Mn(bpia)(OAc)(OCH(3))](PF(6)) (1), [Mn(bipa)(OAc)(OCH(3))](PF(6)) (2), [Mn(bpia)(Cl)(2)](ClO(4)) (3), [Mn(bipa)(Cl)(2)](ClO(4)) (4), [Mn(Hmimppa)(Cl)(2)] x CH(3)OH (5), and [Mn(mimppa)(TCC)] x 2CHCl(3) (6) (bpia = bis(picolyl)(N-methylimidazole-2-yl)amine; bipa = bis(N-methylimidazole-2-yl)(picolyl)amine; Hmimppa = ((1-methylimidazole-2-yl)methyl)((2-pyridyl)methyl)(2-hydroxyphenyl)amine; TCC = tetrachlorocatechol) were synthesized and characterized by various techniques such as X-ray crystallography, mass spectrometry, IR, EPR, and UV/vis spectroscopy, cyclic voltammetry, and elemental analysis. 1 and 2 crystallize in the triclinic space group Ponemacr; (No. 2), 4 and 6 crystallize in the monoclinic space group P2(1)/n (No. 14), and 5 crystallizes in the orthorhombic space group Pna2(1). Complexes 1-4 are structurally related to the proposed active site of the manganese-dependent extradiol-cleaving catechol dioxygenase exhibiting an N(4)O(2) donor set (1 and 2) or N(4)Cl(2) donor set (3 and 4). Cyclic voltammetric data show that the substitution of oxygen donor atoms with chloride causes a shift of redox potentials to more positive values. These compounds show high catalytic activity regarding the oxidation of 3,5-di-tert-butylcatechol to 3,5-di-tert-butylquinone exhibiting saturation kinetics at high substrate concentrations. The turnover numbers k(cat) = (86 +/- 7) h(-1) (1), k(cat) = (101 +/- 4) h(-1) (2), k(cat) = (230 +/- 4) h(-1) (3), and k(cat) = (130 +/- 4) h(-1) (4) were determined from the double reciprocal Lineweaver-Burk plot. Compounds 5 and 6 can be regarded as structural and electronic Mn analogues for substituted forms of Fe-containing intradiol-cleaving catechol dioxygenases. To our knowledge 5 is the first mononuclear Mn(II) compound featuring an N(3)OCl(2) donor set.     

Synthesis, reactivity studies, structural aspects, and solution behavior of half sandwich ruthenium(II) N,N',N'-triarylguanidinate complexes

[(η(6)-C(10)H(14))RuCl(μ-Cl)](2) (η(6)-C(10)H(14) = η(6)-p-cymene) was subjected to a bridge-splitting reaction with N,N',N'-triarylguanidines, (ArNH)(2)C═NAr, in toluene at ambient temperature to afford [(η(6)-C(10)H(14))RuCl{κ(2)(N,N')((ArN)(2)C-N(H)Ar)}] (Ar = C(6)H(4)Me-4 (1), C(6)H(4)(OMe)-2 (2), C(6)H(4)Me-2 (3), and C(6)H(3)Me(2)-2,4 (4)) in high yield with a view aimed at understanding the influence of substituent(s) on the aryl rings of the guanidine upon the solid-state structure, solution behavior, and reactivity pattern of the products. Complexes 1-3 upon reaction with NaN(3) in ethanol at ambient temperature afforded [(η(6)-C(10)H(14))RuN(3){κ(2)(N,N')((ArN)(2)C-N(H)Ar)}] (Ar = C(6)H(4)Me-4 (5), C(6)H(4)(OMe)-2 (6), and C(6)H(4)Me-2 (7)) in high yield. [3 + 2] cycloaddition reaction of 5-7 with RO(O)C-C≡C-C(O)OR (R = Et (DEAD) and Me (DMAD)) (diethylacetylenedicarboxylate, DEAD; dimethylacetylenedicarboxylate, DMAD) in CH(2)Cl(2) at ambient temperature afforded [(η(6)-C(10)H(14))Ru{N(3)C(2)(C(O)OR)(2)}{κ(2)(N,N')((ArN)(2)C-N(H)Ar)}]·xH(2)O (x = 1, R = Et, Ar = C(6)H(4)Me-4 (8·H(2)O); x = 0, R = Me, Ar = C(6)H(4)(OMe)-2 (9), and C(6)H(4)Me-2 (10)) in moderate yield. The molecular structures of 1-6, 8·H(2)O, and 10 were determined by single crystal X-ray diffraction data. The ruthenium atom in the aforementioned complexes revealed pseudo octahedral "three legged piano stool" geometry. The guanidinate ligand in 2, 3, and 6 revealed syn-syn conformation and that in 4, and 10 revealed syn-anti conformation, and the conformational difference was rationalized on the basis of subtle differences in the stereochemistry of the coordinated nitrogen atoms caused by the aryl moiety in 3 and 4 or steric overload caused by the substituents around the ruthenium atom in 10. The bonding pattern of the CN(3) unit of the guanidinate ligand in the new complexes was explained by invoking n-π conjugation involving the interaction of the NHAr/N(coord)Ar lone pair with C═Nπ* orbital of the imine unit. Complexes 1, 2, 5, 6, 8·H(2)O, and 9 were shown to exist as a single isomer in solution as revealed by NMR data, and this was ascribed to a fast C-N(H)Ar bond rotation caused by a less bulky aryl moiety in these complexes. In contrast, 3 and 10 were shown to exist as a mixture of three and five isomers in about 1:1:1 and 1·0:1·2:2·7:3·5:6·9 ratios, respectively in solution as revealed by a VT (1)H NMR, (1)H-(1)H COSY in conjunction with DEPT-90 (13)C NMR data measured at 233 K in the case of 3. The multiple number of isomers in solution was ascribed to the restricted C-N(H)(o-tolyl) bond rotation caused by the bulky o-tolyl substituent in 3 or the aforementioned restricted C-NH(o-tolyl) bond rotation as well as the restricted ruthenium-arene(centroid) bond rotation caused by the substituents around the ruthenium atom in 10.     

A Raman microprobe study of melt inclusions in kimberlites from Siberia, Canada, SW Greenland and South Africa

The geometries, energies and vibrational frequencies of various polyborates in both gaseous and aqueous phase were calculated at the B3LYP/aug-cc-pVDZ level. The calculated total symmetrical stretching Raman shifts of B(OH)(3), B(OH)(4)(-), B(2)O(OH)(4), B(2)O(OH)(5)(-), B(2)O(OH)(6)(2-), B(3)O(3)(OH)(3), B(3)O(3)(OH)(4)(-), B(3)O(3)(OH)(5)(2-), B(3)O(3)(OH)(6)(3-), B(4)O(5)(OH)(4)(2-) and B(5)O(6)(OH)(4)(-) were assigned to 877.40, 735.33, 785.22, 792.90, 696.79, 587.72, 599.06, 740.16, 705.01, 551.67 and 521.04cm(-1), respectively. The results can be used as the characteristic frequency for polyborates in aqueous phase at room temperature. At least six types of polyborates B(OH)(3), B(OH)(4)(-), B(3)O(3)(OH)(4)(-), B(3)O(3)(OH)(5)(2-), B(4)O(5)(OH)(4)(2-) and B(5)O(6)(OH)(4)(-), occur in aqueous solutions at ambient temperature. The chemical species distribution and the relevant interaction mechanisms among polyborates in the solutions were also suggested.     

Rossicasins A, B and rosicaside F, three new phenylpropanoid glycosides from Boschniakia rossica

Three phenylpropanoid glycosides have been isolated, together with the known phenylpropanoid glycosides rossicaside A (4), B (5), E (6), and trans-p-coumaryl alcohol 1-O-beta-D-glucopyranosyl(1-->4)-alpha-L-rhamnopyranosyl(1-->3)-beta-D-glucopyranoside (7), and an acylated oligosaccharide beta-D-glucopyranosyl(1-->4)-alpha-L-rhamnopyranosyl-(1-->3)-(4-O-trans-caffeoyl)-D-glucopyranose) (8), from the aqueous extract of Boschniakia rossica (CHAM. et SCHLECH.) FEDTSCH. et FLEROV. Spectroscopic evidence led to the assignments of their structures as trans-p-coumaryl-(6'-O-beta-D-xylopyranosyl)-O-beta-D-glucopyranoside (1), trans-p-coumaryl-(6'-O-alpha-L-arabinopyranosyl)-O-beta-D-glucopyranoside (2) and 2-(3,4-dihydroxyphenyl)-R,S-2-ethoxy-ethyl-O-beta-D-glucopyranosyl(1-->4)-alpha-L-rhamnopyranosyl(1-->3)(4-O-trans-caffeoyl)-beta-D-glucopyranoside (3), designated as rossicasin A, rossicasin B, and rossicaside F, respectively. Compound 7 was identified from the degradation reaction and this is the first isolation from a natural source.