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An aqueous solution dissolving pyridoxal 5′-phosphate (PLP) was exposed to sun-light at room temperature to yield a photolysis product, 4b,9b-dihydro-4b,9b-dihydroxy-1,6-dimethyl-4,9-bis(phosphonooxymethyl){pyrido[3′,4′:2,3]furo[4,5- b ]}pyrido[4,3- d ]furan ( 1 ), whose structure was crystallographically determined. The product 1 was found to be a novel C(sp 3 )–C(sp 3 ) side-sharing pyridodihydrofuran-condensed skeleton compound with the two pyridodihydrofuran planes taking a ‘V-shape’-like molecular configuration. Hydrogen bonding patterns of molecules of 1 in the crystal lattice are analyzed by the graph set approach. The most probable mechanism for the formation of 1 is described. [ABSTRACT FROM AUTHOR]

• Crystal structure of a dinuclear Rh2+ complex of theophylline was determined. • The Rh‒Rh core is occupied at either axial-side by theophylline ligands through N9. • Metal bonding not to expected N7 but to N9 is due to the crystal packing effect. • A discrete, cyclic hexameric water cluster intercalates between theophylline rings. • Metal binding sites of theophylline are reviewed in terms of interligand interaction. Reaction of theophylline with [Rh 2 (μ-OAc) 2 (μ-HNOCCF 3) 2 ] gave [Rh 2 (μ-OAc) 2 (μ-HNOCCF 3) 2 (theophylline) 2 ]·6H 2 O (1), whose crystal structure was determined by single-crystal X-ray diffraction. The dirhodium core, where the two different acetato and acetamidato ligands bridging the Rh‒Rh bond are in a trans configuration, is occupied at either axial-side by two theophylline ligands through N(9) with the formation of two kinds of intra-molecular interligand C−H (theophylline)···O hydrogen bonds, one being a bifurcated hydrogen bond between the C(3)-methyl hydrogen as a donor and the acetato and amidato oxygens as acceptors and the other between the C(8) hydrogen and the acetato oxygen. In the crystal lattice, a discrete, hydrogen-bonding, cyclic hexameric water cluster with the flattened chair conformation is sandwiched between theophylline bases, providing the first water hexagon that intercalates between aromatic rings. The participation of the acetamidato NH group in the formation of a hydrogen bond with a water molecule belonging to the water hexagon that governs the crystal packing makes it impossible for the acetamidato ligand to form an intra-molecular hydrogen bond with O(6), causing the failure of the metal bonding to theophylline through N(7). A critical review on metal bonding properties of theophylline observed in so far reported crystal structures is given, emphasizing the significance of intra-molecular interligand interactions (H-bonding, electrostatic repulsion, and steric constraint) as a factor that could affect metal binding sites/modes of theophylline. [ABSTRACT FROM AUTHOR]

Abstract: Metal ions play a key role in nucleic acid structure and activity. The elucidation of factors/rules that govern the binding of metal ions is therefore an essential step for the better understanding of nucleic acid functions. In this review, we deal with stereospecific intra-molecular interligand interactions as such a factor, involving hydrogen-bonding, electrostatic interaction, and steric constraints, especially focusing on their significance as a factor that could affect base-specific metal bonding to adenine and guanine bases in the solid state. [Copyright &y& Elsevier]

Abstract: We focused on the iron-complexes of sanshools (hydroxyl-α-sanshool, hydroxyl-β-sanshool, and γ-sanshool) as the key intermediates for the selective synthesis of these structurally unstable compounds. Consequently, we developed a concise and selective method for the total synthesis of sanshools in 5–6 steps (26–45% overall yield), including complexation of dienes with iron tricarbonyl group. [Copyright &y& Elsevier]

Abstract: Reaction between xanthine, tris(2-aminoethyl)amine (tren) and M(ClO4)2 (M=Zn2+, Cd2+, Ni2+ or Cu2+) under alkaline conditions gave five ternary tren–metal ion–xanthine complexes, among which crystal structures of [Zn(tren)(H2xan)]·ClO4 ·H2O (1), [Cd(tren)(H2xan)]·ClO4 ·H2O (2), [Ni(tren)(H2xan)(H2O)]·ClO4 ·H2O (3), and [Cu2{(μ-Hxan)Cu(tren)}2(μ-Hxan)2(H2O)2]·10H2O (4) (H3xan=neutral xanthine) were determined by X-ray diffraction. In the Zn2+ (1) and Cd2+ (2) complexes, which are isostructural to each other, the tren-capped metal ion binds to xanthine through N(7) with the formation of an intramolecular interligand hydrogen bond between the amino nitrogen of tren and O(6) of the base. The Ni2+ complex (3) involves the metal bonding to N(7) of the base with the formation of two intramolecular hydrogen bonds between O(6) of the base and the amino group of tren and the aqua ligand. The tetranuclear Cu2+ complex (4) forms a paddle-wheel type of centrosymmetrical dicopper tetraxanthinate structure, where the two copper ions are bridged by four xanthine ligands through N(3)/N(9) chelation and, in addition, two among the four xanthine ligands are metalated each by the tren-capped copper ion through N(7) with the formation of an intramolecular hydrogen bond between the amino group of tren and O(6) of the base. The significance of intramolecular interligand interaction as a factor that affects site-specific metal bonding is emphasized. A review of metal bonding properties of so far reported xanthine–metal complexes is given. [Copyright &y& Elsevier]

Abstract: Reaction of tris(2-aminoethyl)amine (tren) and Cu(ClO4)2, Ni(ClO4)2, or Ni(NO3)2 with purine nucleobases (adenine, 9-ethylguanine, and hypoxanthine) gave five ternary tren–metal ion–nucleobase complexes, [Ni(tren)(adeninato)(ClO4)]·adenine (1), [Cu(tren)(9-ethylguanine)]·(ClO4)2 (2), [{Ni(tren)(H2O)}2(hypoxanthinato)]·(ClO4)3 ·1.5H2O (3), [Ni(tren)(hypoxanthinato)(H2O)]·ClO4 ·2H2O (4), and [{Ni(tren)(H2O)}2(hypoxanthinato)]2 ·(NO3)6 ·4.5H2O (5), where 1 and 4 were prepared under pH 8–9 while 2, 3, and 5 were under pH 6–7, and their crystal structures were determined by X-ray diffraction. In the adenine complex 1, the tren-capped metal ion binds to the base through N(9) with the formation of an intramolecular interligand hydrogen bond between the amino group of tren and N(3) of the base, and the 9-ethylguanine complex 2 involves the metal bonding to N(7) of the base with the formation of an intramolecular hydrogen bond between the amino group of tren and O(6) of the base. In the hypoxanthine complexes 3 and 5, the metal ions bind to N(7) in addition to N(9), forming three intramolecular hydrogen bonds, two involving O(6) with the amino nitrogen of tren and the aqua ligand and one between the aqua ligand and N(3) of the base, whereas the hypoxanthine complex 4 involves the metal bonding solely to N(9) with the formation of an intramolecular hydrogen bond between the aqua ligand and N(3) of the base, where N(7) as well as N(1) are hemi-protonated. The absence of the metal–N(7) bonding for adenine in 1 while the metal bonding to N(7) specific for guanine derivatives in 2, 3 and 5 are rationalized in terms of interligand interactions. [Copyright &y& Elsevier]

Three silver(I) complexes, [Ag(ca2en)(PPh3)]ClO4 (1), [Ag(ca2en)(PPh3)2]ClO4 (2) and [Ag(ca2en)2]ClO4 (3), where ca2en = N,N′-bis(trans-cinnamaldehyde)ethylenediimine, have been synthesized and characterized spectroscopically. The crystal structure of (1) was determined by X-ray diffraction methods. Crystal data for 1: C38H35AgClN2O4P, triclinic, P1, a = 12.086(2), b = 18.204(2), c = 8.550(2) Å, α = 102.69(1), β = 105.85(1), γ = 91.47(1)°, V = 1758.0(5) Å3, Z = 2, R(F) = 0.070, wR (F) = 0.064, T = 296 K. The coordination geometry of the Ag atom is distorted trigonal involving two N atoms of ca2en and one P atom of triphenylphosphine (PPh3). [ABSTRACT FROM AUTHOR]

Mn(II) complexes Mn[HB(pz)3]2 (1) (pz = pyrazole) and Mn[HB(3,5-Me2-pz)3]2 (2) have been obtained by the reaction of Mn(OOCCH3)2 with NaHB(pz)3 and NaHB(3,5-Me2-pz)3 in MeOH, respectively. The two complexes (1) and (2) were characterized by IR, elemental analyses, and x-ray diffraction. Complex (1) crystallizes in the space group C2/c, a = 18.971(3) Å, b = 13.700(3) Å, c = 19.056(3) Å, β = 111.378(10), V = 4612.0(13) Å3, Z = 2. Complex (2) crystallizes in the space group R-3, a = 10.9832(18) Å, b = 10.983(2) Å, c = 24.785(3) Å, γ = 120°, V = 2589.3(7) Å3, Z = 3. X-ray structure analysis has shown that the complexes (1) and (2) all are monomeric neutral complexes, and possess similar coordination modes around the metal Mn centers. In addition, some related bonding distances, angles, and structural properties are discussed. [ABSTRACT FROM AUTHOR]

V(IV)O(H 2 O) 2 (2,6-pyridinedicarboxylate)·2H 2 O ( 1 ) was obtained by the reaction of VO(acac) 2 with 2,6-pyridine dicarboxylic acid in MeOH and water. Complex ( 1 ) was characterized by IR spectroscopy, element analysis and X-ray diffraction. It crystallizes in space group P . X-ray structure analysis has shown that complex ( 1 ) is a monomeric neutral complex containing vanadyl ion, 2,6-pyridinedicarboxylate ligand and coordinated water, possessing distorted octahedral geometry. Complex ( 1 ) is constructed from mononuclear vanadium, V(IV)O(H 2 O) 2 (2,6-pyridinedicarboxylate) units and crystallization water molecules held together in an extensive two-dimensional network via O-H···O hydrogen bonds, π-π stacking interactions between parallel aromatic pyridines, and face-to-face stacking interactions between parallel carbonyl groups of 2,6-pyridine dicarboxylic acid ligands along the plane formed by the x , z axis of the unit cell. [ABSTRACT FROM AUTHOR]

The V(V) complex VO2(acac)(1,10-phen) (1) has been obtained by the reaction of VO(acac)2 with 1,10-phenanthroline. The complex (1) was characterized by IR, elemental analyses and X-ray diffraction studies which reveal that it crystallizes in the space group P21/c, a = 8.052(4) Å, b = 16.140(6) Å, c = 12.153(4) Å, β = 90.69(15)°, V = 1579.2(11) Å3, Z = 4. It is a monomeric neutral oxovanadium(V) complex containing 1,10-phenaroline and acac as mixed ligands and possessing a disordered octahedron geometry around the vanadium atom. [ABSTRACT FROM AUTHOR]

The reaction of [Rh2(OAc)4] with adenine, 9-methyladenine, 9-ethylguanine, adenosine, guanosine, deoxyguanosine, or inosine in methanolic aqueous solution at room temperature gave specifically and quantitatively pink complexes of adenine or its derivatives (=L), [Rh2(OAc)4(L)] (the dirhodium-core:L ratio of 1:1). The reaction of [Rh2(HNOCCF3)4] or [Rh2(OAc)2(HNOCCF3)2] with these nucleobases or nucleosides (=L) gave non-specifically pink or red complexes with dirhodium-core:L=1:1 for adenine derivatives while 1:2 for guanine derivatives. Recrystallization of a 9-methyladenine adduct from a nitric acid solution yielded [Rh2(OAc)2(HNOCCF3)2(9-methyladeninium)2]·(NO3)2 (1), whose crystal structure was determined by X-ray diffraction, showing that two N(1)-protonated 9-methyladeninium molecules coordinate to both the axial-positions of a [Rh2(OAc)2(HNOCCF3)2] nucleus through N(7) with the formation of an intramolecular interligand N(6)&z.sbnd;H⋯O(acetato) hydrogen bond. Crystal structures of guanine derivatives, [Rh2(OAc)2(HNOCCF3)2(9-ethylguanine)2]·2MeOH·2H2O (2), [Rh2(HNOCCF3)4(L)2]·3H2O (L=guanosine (3), deoxyguanosine (4), or inosine (5)), and [Rh2(OAc)2(HNOCCF3)2(guanosine)2]·3H2O (6) were determined, showing that the dirhodium core is occupied at either axial-side by two guanine or hypoxanthine moieties through N(7) with the formation of an intramolecular interligand N(amidato)&z.sbnd;H⋯O(6) hydrogen bond. Each of guanosine molecules in 3, 4, and 6 or inosine molecules in 5 adopts the syn, gauche–gauche (or gauche–trans for one molecule in 3), and C(2′)-endo (or C(2′)-endo-C(3′)-exo for one molecule in 4) conformations to form an intramolecular O(5′)&z.sbnd;H⋯N(3) hydrogen bond. The formation of interligand N(6)&z.sbnd;H⋯O hydrogen-bonding associated with the sterically constrained octahedral coordination geometry about the rhodium atom bonded to N(7), as observed in 1, and/or to N(1) of adenine may give a structural basis for the adenine-specific reactivity of [Rh2(OOCR)4], where the carboxylato ligand could function as hydrogen-bonding acceptor only. Similarly, the formation of interligand N&z.sbnd;H⋯O(6) hydrogen-bonding observed in 2–6 suggests that [Rh2(HNHNCR)4] could function as guanine-specific reagents, where the amidinato ligand could function as hydrogen-bonding donor only. The interligand steric constraint due to the octahedral coordination geometry may also explain no reactivity of [Rh2(OOCR)4] toward native B-DNA (right-handed double-stranded structure) but specific bonding to single-stranded and possibly to left-handed double-stranded structures. [Copyright &y& Elsevier]

An investigation into the interactions between thiamine monophosphate (TMP) and anions has resulted in the preparation and X-ray characterization of the compounds (TMP)(Hg2Br5)·0.5H2O (1) and (TMP)2(Hg3I8) (2). In each compound the TMP molecule exists as a monovalent cation in the usual F conformation. The halogenomercurate anions occur in two-dimensional (2-D) network in 1 or one-dimensional (1-D) chain in 2. In both 1 and 2, the structures consist of alternating cationic sheets of the hydrogen-bonded TMP molecules and anionic sheets of the polymeric halogenomercurate anions. The TMP molecule binds to the polymeric anions through the characteristic ‘anion bridge I’, C(2)&z.sbnd;H⋯X⋯pyrimidinium (X=Br in 1 and I in 2), and electrostatic interactions between electropositive S(1) and halogen atoms. The ‘anion bridge II’ of the type N(4′1)&z.sbnd;H⋯X⋯thiazolium (X=phosphate group) plays a role in stabilizing the molecular conformation. The biological implication of the host–guest-like complexation between TMP and polymeric anions is discussed. [Copyright &y& Elsevier]

Discusses the interligand interactions affecting site-specific metal bonding. Reaction properties of [Rh2(OAc)4] with damt, dmap, and dmp and crystal structures of the reaction products [Rh2(OAc)4(L)2] (1 for L=damt, 2 for L=dmap, 3 for L=dmp); Impact of inteligand hydrogen bonds on the site to which the Rh atom binds to damt or dmap.

Review: 236 refs. [ABSTRACT FROM AUTHOR]

Two new ligands, N1, N2-Bis(3-phenylallylidene)propane1,2-diamine, ca2men and 1, 2-diphenyl-N, N'-bis(3-phenylallylidene) ethane1, 2-diamine, phca2dpen, and their corresponding copper(I) complexes, [Cu(ca2men)2]BPh4 1 and [Cu(phca2dpen)2]ClO4 2, were synthesized and characterized by C,H,N analyses, IR, and UV/VIS spectroscopy. The crystal and molecular structures of 1 and 2 were determined by X-ray crystallography from single-crystal data. The coordination polyhedron about the CuI center in the two complexes is best described as a distorted tetrahedron. The spectral analysis of the complexes identifies an increasing in wavelength of the first metal to ligand charge transfer band with increasing of the substituents in the ligands. A quasireversible redox behavior is observed for complex 1 and 2 (E1/2= 0.71 and 0.83 V). [ABSTRACT FROM AUTHOR]

The reaction of VO(ph-acac)2 (ph-acac=phenyacetylacetonato) with NaHB(pz)3 (pz=pyrazole) or NaHB(3,5-Me2pz)3 in the solution of MeOH gave oxovanadium (IV) complexes HB(pz)3VO(ph-acac) · 2H2O (1) and HB(3,5-Me2pz)3VO(ph-acac) · 2H2O (2), respectively. An oxovanadium complex, V2O4[HB(pz)3]2 · 2CH3CN (3), was obtained by the reaction of VOSO4 · 3H2O with tri(pyrazolyl)borate sodium in MeOH. The complexes 1, 2 and 3 were characterized by elemental analysis, IR, UV-Vis, NMR. In particular, the crystals of complex 1 and 3 were determined by X-ray diffraction. They crystallize in space group P21/c, a=16.497(5) Å, b=7.6601(19) Å, c=17.199(4) Å, β=107.498(19)°, V=2072.8(9) Å3, Z=4, R=0.0371 (I>2σ(I)) for 1; in the monoclinic, space group Pbca, with cell dimensions of a=15.531(2) Å; b=18.007(2) Å; c=10.725(2) Å; V=2999.4(8) Å3, Z=4, R= 0.0401(I>2σ(I)) for 3. Structure analyses have shown that complex 1 is a monomeric oxovanadium complexe containing polypyrazolylborate and two lattice water. Complex 3 consists of a V2O4(HB(pz)3)2 molecule and two free CH3CN lattice molecules in an unit cell. Both possess a similar coordination mode for the vanadium atom. In addition, luminescence properties and thermal analysis characterization of the complexes also are discussed. [ABSTRACT FROM AUTHOR]

In the structure of the title compound, {[Rh2(C2H3O2)4(C7H18N2O)]·0.5C4H8O} n or {[Rh2(O2CMe)4(Hbdmap)]·0.5C4H8O} n, where Hbdmap is 1,3-bis­(dimethyl­amino)propan-2-ol, each Hbdmap ligand is coordinated to two [Rh2(O2CMe)4] units by two N atoms, resulting in a polymeric chain structure. The observed coordination mode of the Hbdmap mol­ecule is unprecedented. [ABSTRACT FROM AUTHOR]

Resorcin[ 4 ]arene (resorcinol cyclic tetramer, abbreviated as RCT) or pyrogallol[ 4 ]arene (pyrogallol cyclic tetramer, PCT) form host–guest 1:1 complexes with DL-proline (DL-Pro) or l -proline (L-Pro), [RCT·DL-Pro]·2MeOH·3.5H 2 O ( 1 ) and 2[PCT·L-Pro]·2EtOH·10H 2 O ( 2 ), whose crystal structures have been determined. In each complex, the proline ligand is incorporated into the bowl-shaped cavity of RCT or PCT host molecules through C H … π interactions between alkyl protons of the pyrrolidine ring of proline and π-rings of RCT or PCT, forming an [RCT/PCT·Pro] structural fragment. In the crystal lattice, two [RCT/PCT·Pro] fragments self-associate to form a ligand-mediated dimeric structure, [RCT·D-Pro·L-Pro·RCT] in 1 or [PCT·L-Pro·L-Pro·PCT] in 2 . A 1 H NMR solution study gave the host‒ligand binding constants of 10.0 ± 1.1 M –1 for the RCT–DL-Pro system and 17.3 ± 1.3 M –1 for the PCT–L-Pro system. These complexes provide a synthetic model for the recognition of the proline residue in proline-containing substrates or inhibitors by enzymes through C H … π interaction. The CSD survey revealed that the absolute value of the torsion angle N–C α –C O1 (O1 is cis to N) about the carboxyl C α –C bond of proline is significantly smaller than that of the C β –C α –C O2 (O2 is cis to C β ) torsion angle. [ABSTRACT FROM AUTHOR]

Introduction Flavonoids are converted to inactive metabolites like glucuronides in the gut, and circulate mainly as glucuronides in blood stream, resulting in low concentrations of active aglycones in plasma. It is therefore unclear how oral flavonoids exert their effects in tissues. We recently reported the plasma pharmacokinetics of some flavonoids and suggested the possibility that the absorbed flavonoids modified macrophage functions leading to enhance bacterial clearance. We aimed to confirm their pharmacological profiles focusing on tissue macrophages. Methods Pseudoinfection was induced by intradermal injection of FITC-conjugated and killed Staphylococcus aureus into the ears of mice treated with or without genistein 7- O-glucuronide (GEN7G, 1 mg/kg, i.v.). FACS analysis was performed on single cell suspensions dispersed enzymatically from the skin lesions at 6 h post pseudoinfection to evaluate phagocytic activities of monocytes/macrophages (CD11b+Ly6G−) and neutrophils (CD11b+Ly6G+). Phagocytosis of the FITC-conjugated bacteria by four glucuronides including GEN7G was evaluated in cultures of mouse macrophages. Results After GEN7G injection, genistein was identified in the inflamed ears as well as GEN7G, and the phagocytic activity of CD11b+Ly6G− cells was increased. GEN7G was converted to genistein by incubation with macrophage-related β-glucuronidase. Macrophage culture assays revealed that GEN7G increased phagocytosis, and the action was dampened by a β-glucuronidase inhibitor. Binding of aglycones to estrogen receptors (ERs), putative receptors of flavonoid aglycones, correlated to biological activities, and glucuronidation reduced the binding to ERs. An ER antagonist suppressed the increase of macrophage function by GEN7G, whereas estradiol enhanced phagocytosis as well. Conclusions This study suggests a molecular mechanism by which oral flavonoids are carried as glucuronides and activated to aglycones by β-glucuronidase in tissue macrophages, and contributes to the pharmacological study of glucuronides. [ABSTRACT FROM AUTHOR]

Treatment of cytosine with tris(2-aminoethyl)amine (tren) and Cu(ClO 4 ) 2 ·6H 2 O under alkaline conditions gave a ternary tren–Cu 2+ –cytosine complex, [{Cu(tren)} 2 (cytosinato)]·(ClO 4 ) 3 ·0.5H 2 O, whose crystal structure was determined by X-ray diffraction. In the structure of the [{Cu(tren)} 2 (cytosinato)] 3+ cation, two tren-capped square-pyramidal Cu 2+ ions bind to a cytosinate anion, one through the deprotonated N(1) of cytosine with the formation of an intra-molecular interligand hydrogen bond between the keto substituent O(2) of the base and the amino group of tren and the other through both the ring nitrogen N(3) and the exocyclic O(2) of the base, forming a four-membered chelate-ring. An overview on metal bonding properties of N(1)-unsubstituted cytosine observed in so far reported crystal structures is given, emphasizing the significance of intra-molecular interligand interaction as a factor that affects metal-binding sites of cytosine. [ABSTRACT FROM AUTHOR]

Background: Rikkunshito, a traditional Japanese (Kampo) medicine, has been used to treat upper gastrointestinal disorders such as functional dyspepsia and gastroesophageal reflux. This study investigated the exposure and pharmacokinetics of the ingredients of rikkunshito in healthy volunteers. Methods and Results: First, an exploratory nonrandomized, open-label, one-period, noncrossover study using four healthy Japanese volunteers to detect 32 typical ingredients of rikkunshito in plasma and urine. As a result, 18 or 21 of 32 ingredients was detected in plasma or urine samples after oral administration of rikkunshito (7.5 g/day). Furthermore, a randomized, open-label, three-arm, three-period, crossover study using 21 subjects was conducted to determine the amounts of exposure and pharmacokinetic parameters of nine ingredients derived from rikkunshito (atractylodin, atractylodin carboxylic acid, pachymic acid, 3,3′,4′,5,6,7,8-heptamethoxyflavone, naringenin, nobiletin, liquiritigenin, isoliquiritigenin, and 18β-glycyrrhetinic acid) after oral administration of rikkunshito at three different doses (2.5, 5.0, or 7.5 g/day) during each period. The pharmacokinetic profiles of the nine ingredients in plasma were characterized. The geometric means (95% confidence interval) for the Cmax of the ingredients at a dose of 7.5 g were 1570 (1210–2040), 14,300 (12,200–16,800), 91.0 (71.8–115), 105 (75.6–144), 1150 (802–1650), 35.9 (24.6–52.5), 800 (672–952), 42.8 (30.4–60.3), and 55,600 (39,600–78,100) pg/mL, respectively, and for the AUC0–last were 1760 (1290–2390), 12700 (11,100–14,600), 1210 (882–1650), 225 (157–322), 4630 (2930–7320), 35.7 (20.4–62.7), 4040 (3260–5010), 122 (88.2–168), and 832,000 (628,000–1,100,000) pg·h/mL respectively. Conclusions: We identified the ingredients of rikkunshito that are absorbed in humans. Furthermore, we determined the pharmacokinetics of nine ingredients derived from rikkunshito. This information will be useful for elucidating the pharmacological effects of rikkunshito. Trial Registration: Japan Pharmaceutical Information Center [ABSTRACT FROM AUTHOR]

Highlights: [•] Host–guest complexation of aromatic cyclic tetramers (RCT or PCT) with pipecolinic acid (pipeH) in crystal and in solution. [•] Piperidine ring of pipeH incorporated into the cavity of RCT or PCT through C–H⋯π interactions with π-rings of RCT or PCT. [•] Ligand-mediated capsule-like dimeric structures, [(RCT or PCT)·L-pipeH·D-pipeH·(RCT or PCT)], are formed. [•] A model for the recognition of the pipecolinyl ring of FK506 by its binding protein through C–H⋯π interaction is provided. [•] C–H⋯π interaction as a strategy for the structure-based drug design is suggested. [ABSTRACT FROM AUTHOR]

Abstract: Single crystal X-ray analysis of the complex formed between pyrogallo[4]arene (1) and phosphocholine (PCh), [Ca(H2O)3(1)2]·(PCh−)2·2EtOH·5H2O, a model compound that mimics PCh–receptor recognition in biological systems, has shown that PCh is incorporated into the bowl-shaped cavity of 1 through cation–π interactions between the quaternary cationic trimethylammonium group of PCh and π-rings of 1. The hepta-coordinated [Ca(H2O)3]2+ ion is directly bound to two molecules of 1 through phenolic oxygens to form a dimeric molecule of 1, [1{Ca(H2O)3}1]2+. Conformational data of PCh and its derivatives observed in known crystal structures are compiled, focusing on the conformation about the C–C bond in the P–O–C–C–N+ backbone with a reemphasis that the usually observed gauche conformation could be stabilized by an intramolecular N+–C(methyl group)–H⋯O hydrogen bonding. [Copyright &y& Elsevier]

Bis(oxazolinyl)phenylrhodium(III) aqua complexes, (Phebox)RhX2(H2O) [X = Cl, Br], were found to be efficient Lewis acid catalysts for the enantioselective addition of allyl- and methallyltributyltin reagents to amino aldehydes. The reactions proceed smoothly in the presence of 5-10 mol % of (Phebox)RhX2(H2O) complex at ambient temperature to give the corresponding amino alcohols with modest to good enantioselectivity (up to 94% ee). [ABSTRACT FROM AUTHOR]

Abstract: Reaction of 1,4,7,10-tetraazacyclododecane (cyclen) and Cu(ClO4)2·6H2O with nucleobases (adenine, hypoxanthine, xanthine, theophylline, cytosine, or uracil) under alkaline conditions gave four ternary cyclen–metal–nucleobase complexes, [Cu(cyclen)(adeninato)]·ClO4·2H2O (1), [{Cu(cyclen)}2(hypoxanthinato)]·(ClO4)3 (2), [Cu(cyclen)(theophyllinato)]3·(ClO4)3·2H2O (3), and [Cu(cyclen)(xanthinato)]·(0.7ClO4)·(0.3ClO4)·3H2O·(0.5H2O)3 (4), whose crystal structures were determined by X-ray diffraction. In the adenine complex 1, a cyclen-capped square–pyramidal Cu2+ ion binds to an adeninato ligand through N(9) with the formation of an intramolecular interligand hydrogen bond between the secondary amino nitrogen of cyclen and N(3) of the base. In the hypoxanthine complex 2, two cyclen-capped Cu2+ ions bind to a hypoxanthinato ligand, one through N(7) with the formation of an intramolecular N(cyclen)–H···O(6) hydrogen bond and the other through N(9) to form an intramolecular N(cyclen)–H···N(3) hydrogen bond. Similarly, in both the theophylline complex 3 and the xanthine complex 4, each cyclen-capped Cu2+ ion binds to a theophyllinato or xanthinato ligand through N(7) with the formation of an intramolecular N(cyclen)–H···O(6) hydrogen bond. However, unlike in 2, steric constraints between amino group(s) of cyclen and the methyl group at N(3) of theophylline in 3 or the proton attached to N(9) of xanthine in 4 preclude the metal bonding to N(9) in 3 or N(3) in 4. The significance of intramolecular interligand interaction as a factor that affects metal-binding site(s) on nucleobases is emphasized. [Copyright &y& Elsevier]

Abstract: Reaction between nucleobases (adenine, hypoxanthine, cytosine, and uracil), tris(2-aminoethyl)amine (tren) and M(ClO4)2 (M2+ =Zn2+, Cd2+, Ni2+ or Cu2+) under pH 8–9 gave eight ternary tren-metal ion-nucleobase complexes, among which seven crystal structures, [Zn(tren)(adeninato)]·ClO4 (1), [Cd(tren)(adeninato)]·ClO4 (2), [Ni(tren)(adeninato)(ClO4)] (3), [Zn(tren)(hypoxanthinato)]·ClO4 ·H2O (4), [{Cd(tren)}2(hypoxanthinato)]·(ClO4)3 ·0.5 H2O (5), [Ni(tren)(uracilato)(H2O)]·ClO4 ·(0.5H2O)2 (7), and [Cu(tren)(uracilato)]·ClO4 ·0.5H2O (8) were determined by X-ray diffraction. In each of the adenine complexes with Zn2+ (1), Cd2+ (2), and Ni2+ (3), among which 1 and 2 are isostructural to each other, a tren-capped metal ion binds to an adeninato ligand through N(9) with the formation of an intramolecular interligand hydrogen bond between the amino nitrogen of tren and N(3) of the base. In the hypoxanthine complexes 4 and 5, a tren-capped Zn2+ ion in 4 binds to a hypoxanthinato ligand through N(9) with the formation of an intramolecular N(tren)–H⋯N(3) hydrogen bond, while in 5 two tren-capped Cd2+ ions bind to a hypoxanthinato ligand, one through N(7) with the formation of an intramolecular N(tren)–H⋯O(6) hydrogen bond and the other through N(9) to form an intramolecular N(tren)–H⋯N(3) hydrogen bond. In each of the uracil complexes with Ni2+ (7) and Cu2+ (8), a tren-capped metal ion binds to an uracilato ligand through N(1) with the formation of an intracomplex O(aqua)–H⋯O(2) hydrogen bond in 7 or an intramolecular N(tren)–H⋯O(2) hydrogen bond in 8. Tren-capped metal ion-bonded nucleobases act as building blocks for the assembly of supramolecular structures, by versatile hydrogen bonding and/or stacking abilities of nucleobases. The significance of intramolecular interligand interaction as a factor that affects metal-binding site(s) on nucleobases is emphasized. [Copyright &y& Elsevier]

Summary: The crystal structures of three vancomycin complexes with two vancomycin-sensitive cell-wall precursor analogs (diacetyl-Lys-d-Ala-d-Ala and acetyl-d-Ala-d-Ala) and a vancomycin-resistant cell-wall precursor analog (diacetyl-Lys-d-Ala-d-lactate) were determined at atomic resolutions of 1.80 Å, 1.07 Å, and 0.93 Å, respectively. These structures not only reconfirm the “back-to-back” dimerization of vancomycin monomers and the ligand-binding scheme proposed by previous experiments but also show important structural features of strategies for the generation of new glycopeptide antibiotics. These structural features involve a water-mediated antibiotic–ligand interaction and supramolecular structures such as “side-by-side” arranged dimer-to-dimer structures, in addition to ligand-mediated and “face-to-face” arranged dimer-to-dimer structures. In the diacetyl-Lys-d-Ala-d-lactate complex, the interatomic O⋯O distance between the carbonyl oxygen of the fourth residue of the antibiotic backbone and the ester oxygen of the d-lactate moiety of the ligand is clearly longer than the corresponding N–H⋯O hydrogen-bonding distance observed in the two other complexes due to electrostatic repulsion. In addition, two neighboring hydrogen bonds are concomitantly lengthened. These observations provide, at least in part, a molecular basis for the reduced antibacterial activity of vancomycin toward vancomycin-resistant bacteria with cell-wall precursors terminating in –d-Ala-d-lactate. [Copyright &y& Elsevier]

Abstract: Novel coordination polymers of the type, [(H2en)(ntpMCl2)] n [M=ZnII (1), CdII (2), HgII (3), ntp=3,3′,3″-nitrilotripropionic acid, en=ethylenediamine] have been prepared by the reaction of a tripodal ligand, ntp, and MCl2 in the presence of en. Ntp, which exists as a zwitterion [NH+(CH2CH2COOH)2(CH2CH2COO)−] in aqueous medium, results in a ditopic anion, ntp2−, on successive deprotonation by en. Thus en acts as a cation based template resulting in coordination polymers involving [ntpMCl2]−2 building units, maintained via hydrogen bonding interactions. The compounds have been characterized by elemental analyses, conductivity, IR and 1H NMR spectroscopic studies. Single crystal X-ray analyses of the compound 1 shows a single stranded helicate architecture where the coordination number four around the zinc ion is maintained by two oxygen donors from ntp2− ligands and two chloride anions. Diquaternary ammonium H2en2+ cations are incorporated into the groove of the helical chain, , by forming hydrogen bonds. A fluorescence measurement study on compound 1 reveals a good binding ability to the DNA helix. [Copyright &y& Elsevier]

Chiral 4,5-bis(2-oxazolinyl)-(2,7-di-tert-butyl-9,9-dimethyl)-9H-xanthenes (xabox) were synthesized and the chiral environments were evaluated in catalytic asymmetric 1,3-dipolar cycloaddition reactions of nitrones resulting in good to excellent enantioselectivities. 1,3-Dipolar cycloaddition reactions of nitrones with 3-crotonoyl-2-oxazolidinone in the presence of a bis(2-oxazolinyl)xanthene (4c; xabox-Bn) and Mn(II) or Mg(II) complex as a chiral Lewis acid catalyst proceeded smoothly to give the corresponding cycloadducts ranging from 96:4 to >99:1 of endo:exo ratio and ranging from 91% to 98% ee for the endo adduct. [Copyright &y& Elsevier]

The Japanese traditional medicine maobushisaishinto (MBST) has been prescribed for treating upper respiratory tract infections, such as a common cold. However, its mode of action is poorly understood, especially concerning the MBST constituent Asiasari Radix (AR). In this study, we focused on AR, with an objective of clarifying its bioavailable active ingredients and role within MBST by performing pharmacokinetic and pharmacological studies. Firstly, we performed qualitative non-targeted analysis utilizing high-resolution mass spectrometry to explore the bioavailable ingredients of AR as well as quantitative targeted analysis to reveal plasma concentrations following oral administration of MBST in rats. Secondly, we performed in vitro pharmacological study of bioavailable AR ingredients in addition to other ingredients of MBST to confirm any agonistic activities against transient receptor potential (TRP) channels. As a result, methyl kakuol and other compounds derived from AR were detected in the rat plasma and showed agonistic activity against TRPA1. This study suggests that methyl kakuol as well as other compounds have the potential to be an active ingredient in AR and thus presumably would contribute in part to the effects exerted by MBST. [ABSTRACT FROM AUTHOR]

In the title complex, [Ag(C26H36N4)2](C24H20B), the AgI atom has a distorted tetrahedral coordination. The organic ligand is bidentate, coordinating the AgI atom via two imine N atoms. One of the cycloheptyl groups and the Ag atom are disordered over two sites, with occupancy factors of ca 0.87 and 0.13. In this arrangement, the closest methylene group is more remote and the Ag atom also moves out by 0.405 (5) Å toward an alternative position. [ABSTRACT FROM AUTHOR]

The structure of poly[3-[(4-amino-2-methylpyrimidin-1-ium-5-yl)meth­yl]-5-(2-hydroxy­ethyl)-4-methyl­thia­zolium octa-μ-bromo/chloro­(4.4/3.6)-tricadmate(II)], {(C12H18N4OS)[Cd3 Br4.41Cl3.59]} n consists of hydrogen-bonded thia­mine mol­ecules and polymeric cadmium bromide/chloride anions in an organic–inorganic hybrid fashion. The one-dimensional anion ribbons are formed by edge-sharing octa­hedra and vertex-sharing tetra­hedra. Thia­mine mol­ecules adopting the S conformation are linked to anions via three types of inter­actions, namely an N(amino)—H⋯anion⋯thia­zolium bridging inter­action, an N(pyrimidine)—H⋯anion hydrogen bond and an O(hydr­oxy)—H⋯anion hydrogen bond. [ABSTRACT FROM AUTHOR]

The title compound, 3-[(4-amino-2-methyl­pyrimidin-5-yl)­meth­yl]-5-(2-hydroxy­eth­yl)-4-methyl­thia­zolium tetra­phenyl­borate monohydrate, C12H17N4OS+·C24H20B−·H2O, is a salt in which the thiamine cations are linked by hydrogen bonds into a two-dimensional network having (4,4)-topology. The stacked sheets form channels, which are occupied by the anions; the cations and anions are linked by C—H⋯π(arene) hydrogen bonds. [ABSTRACT FROM AUTHOR]