Volume 69, Issue 9-10

The structure of hormaomycin has been determined in two crystals grown under different conditions, i. e. in the absence and in the presence of magnesium chloride. In both crystals, the macrocyclic hexadepsipeptide assumes a rather flat conformation, and the dipeptide side chain resides in the same equatorial plane. This is a significant difference in comparison with the compact bent conformation of hormaomycin in solution, as previously determined by an extensive NMR study

Introduction of sulfur into the 5-position of 1,4-disubstituted quaternary 1,2,4-triazolium salts (1-9; Cl, Br, I, BF 4 , PF 6 , CH 3 OSO 3 were used as anions) by two methods was investigated. The syntheses of nine 1,4-disubstituted 1,2,4-triazoline-5-thiones 10-18 are reported (1, 10: R 1 = CH 3 , R 2 = CH 3 ; 2, 11: R 1 = NH 2 , R 2 = CH 3 ; 3, 12: R 1 = NH 2 , R 2 = CH(CH 3 ) 2 ; 4, 13: R 1 = N(CH 3 ) 2 , R 2 = CH 3 ; 5, 14: R 1 = N(CH 3 ) 2 , R 2 = CH(CH 3 ) 2 ; 6, 15: R 1 = CH 3 , R 2 = NH 2 ; 7, 16: R 1 = OCH 2 Ph, R 2 = CH 3 ; 8, 17: R 1 = OCH 2 Ph, R 2 = CH 2 CH 3 ; 9, 18: R 1 = CH 3 , R 2 = CH 2 Ph). Compounds 11-17 represent 1-amino, 4-amino, 4-dimethylamino, and 4-benzyloxy-1,2,4-triazoline-5- thiones, whereas 10 served as a reference compound. Thione 18 was identified as an unexpected by-product in the synthesis of 16 and was also prepared independently. Thermolysis of 10 in air gave 1,4-dimethyl-1,2,4-triazolium hydrogensulfate. Crystal structures of eight 1,4-disubstituted 1,2,4- triazoline-5-thiones were determined by single-crystal X-ray diffraction. Intermolecular hydrogen bonds (C-H···S, C-H···N, N-H···N, N-H···S) were observed in the solid state. The solvent-dependent 1 H NMR chemical shifts of signals of 10 and 13 were satisfactorily correlated with the Kamlet- Abboud-Taft π* and b parameters in ten solvents. From the lack of correlation with the a parameter and from the C=S bond length (average 1.67 Å) a significant contribution of a mesoionic imidazolium-2-thiolate resonance structure seems unlikely

2,4-Bis(2,5-dipropyloxyphenyl)-6-phenylpyridine (6), obtained by a one-pot reaction of enone 3, ketone 4 and ammonium acetate (5), is characterized by its molecular structure in the crystalline state, which deviates far from planarity. The interplanar angles of the three benzene rings amount up to 46° in relation to the central pyridine ring

In the present investigation, the key intermediate acetohydrazide derivative 5 was synthesized starting from 3-(4-methoxybenzyl)-4-amino-4,5-dihydro-1,2,4-triazol-5-one (1) by a four-step reaction. Thiosemicarbazides 6a-f and arylidenehydrazide derivatives 8a-d were obtained from compound 5. The cyclization of compounds 6a-f in the presence of NaOH resulted in the formation of compounds 7a-f. The compounds were characterized by IR, 1 H NMR, 13 C NMR spectroscopy, elemental analysis and mass spectral studies. The compounds were tested for their anti-lipase, anti-α-glucosidase and anti-mycobacterial activities. Compounds 6b and 8c exhibited excellent anti-lipase activity, and compound 8d showed excellent anti-a-glucosidase activity. Compounds 3 and 4 exhibited good antituberculosis activity

A metal-free, PPh 3 -mediated borylation reaction of arenediazonium salts with bis(pinacolato)diborane has been developed under mild conditions. The process provides an attractive alternative to the traditional preparation of arylboronates, albeit in moderate yields

A new compound containing mono- and dinuclear Cu(II) complexes, [Cu 2 (phen) 2 (H 2 O) 2 (OH) 2 ] [Cu(phen) 2 (CO 3 )] 2 (HCO 3 ) 2 · 22H 2 O] (phen=1,10-phenanthroline), has been prepared and characterized by X-ray diffraction analysis, thermoanalytical techniques and temperature-dependent magnetic susceptibility measurements. The hydroxo-bridged dinuclear [Cu 2 (phen)2(H 2 O) 2 (OH) 2 ] 2+ complex cations and the mononuclear [Cu(phen) 2 (CO 3 )] complex molecules are assembled via π···π stacking interactions into layers. A novel water tape containing (H 2 O) 22 cluster units has been observed in the structure of the title complex. In hydrogen bond interactions HCO 3 - anions act as donor and acceptor to link the water tapes to form an infinite 2D network parallel to (010). According to the magnetic analyses, the coupling interactions in the dinuclear complex cation is ferromagnetic (J=34:5 cm -1 )

Reddish-brown crystals of [Na(12-crown-4) 2 ]I 3 (1) and [Rb(12-crown-4) 2 ]I 3 (2) were formed through the reaction of NaI or RbI, I 2 and 12-crown-4 in ethanol. Both structures are triclinic, space group P1 with Z = 2. The lattice parameters are a = 8:505(2), b = 14:280(3), c = 10:695(2) Å and α = 89:86(2)°, β = 80:00(2)° and γ = 85:90(2)°; and a = 10:694(2), b = 11:598(2), c = 12:718(2) Å and α = 71:00(2)°, β = 86:97(2)° and γ = 67:710(10)° for 1 and 2, respectively. Both crystal structures contain one independent complex cation without crystallographic symmetry. The anionic parts of both structures consist of two crystallographically independent, isolated, triiodide anions I 3 - with crystallographic inversion symmetry. The cations are distorted sandwich-like complexes with two 12-crown-4 molecules surrounding the alkali metal atom in the center.

Polycrystalline CeNiIn 4 was prepared by arc-melting of the elements and subsequent annealing at 970 K in vacuum. EuNiIn 4 and EuCuIn 4 were synthesized from the elements by reactions in sealed tantalum tubes. These indium-rich compounds crystallize with the YNiAl 4 -type structure which was refined for EuCuIn 4 from single-crystal X-ray diffraction data: Cmcm, a=450:04(9), b=1698:7(4), c = 740:2(2) pm, wR2 = 0:0606, 495 F 2 values, 24 variables. The EuCuIn 4 structure is built up from a complex three-dimensional [CuIn 4 ] polyanion (265 - 279 pm Cu-In and 296 - 331 pm In- In) in which the europium atoms occupy distorted hexagonal channels. The Eu-Eu distances within these channels (450 pm) are significantly shorter than the distances between Eu atoms in neighboring channels (552 pm). The magnetic properties and the specific heats of the europium compounds have been investigated. Both europium compounds show the magnetism of divalent Eu ions and antiferromagnetic ordering at low temperatures. EuCuIn 4 is magnetically ordered via a surprisingly complex sequence of three transitions

Polycrystalline samples of the stannides Li 2 CuSn 2 and Li 2 AgSn 2 were obtained by high-frequency melting of the elements in sealed niobium ampoules in a water-cooled sample chamber. Both stannides crystallize with the tetragonal Li 2 AuSn 2 type, space group I4 1 /amd. They are characterized by three-dimensional [CuSn 2 ] δ- , respectively [AgSn2] δ- networks which leave large channels for the lithium ions. Electronic structure calculations show extensive filling of the transition metal d bands and residual DOS at the Fermi energy, compatible with metallic character. Calculated Bader charges and the course of the crystal orbital overlap population curves fully support the bonding picture of cationic lithium and a covalently bonded polyanionic network with considerable charge transfer to both, transition metal and tin atoms. Electrochemical investigations have indicated that a reversible insertion and extraction of lithium into the stannides is taking place in the voltage range between 0 and 2:5 V vs. Li=Li + . From CV measurements, the diffusion coefficents of Li 2 CuSn 2 and Li 2 AgSn 2 were estimated to be in the order of 10 -14 cm 2 s -1

An investigation of the petroleum ether extract from Ixeris chinensis Nakai has led to the isolation of a new compound, 3-O-acetyl-22,28-cyclobauer-7-en-3β-ol (1), together with four known compounds which have been isolated from this plant for the first time, namely taraxast-20-en-3β-ol (2), 3-O-acetyl-taraxast-20-en-3β-ol (3), taraxast-20(30)-en-3β-ol (4), and 3-O-acetyl-taraxast-20(30)- en-3β-ol (5). The structures of the isolated compounds have been elucidated on the basis of spectroscopic methods including UV, IR, ESI-MS, 1D NMR, 2D NMR techniques, and by comparison with data reported in the literature. All compounds have been evaluated for their activity against various bacteria and shown to give good results

Fifteen new mono- and bisdesmosidic triterpene saponins, named pittangretosides J, K, M, Q- Z, A 1 , and B 1 , along with three known compounds were isolated from the leaves of Pittosporum angustifolium. By spectroscopic, mass spectrometric and chemical evidence, their structures were established as glycosides of A 1 - and R 1 -barrigenol, barringtogenol C and camelliagenin A backbones

The reaction of Cu(NO 3 ) 2 ·3H 2 O with N 1 ,N 2 -di(pyridin- 4-yl)oxalamide (L) and KSCN in the presence of DMF by the layering method gives rise to a new complex [Cu(L 2 )(SCN) 2 (DMF) 2 ] n (1). Complex 1 has been characterized by single-crystal and powder X-ray diffraction, IR spectroscopy, and elemental and thermogravimetric analyses. It crystallizes in the triclinic system with space group P1̅ and shows a chain structure. Delicate N-H···O hydrogen bonding exists in individual units, and adjacent chains are linked by intermolecular interactions, resulting in an extended 2D network.

The ternary lithium bismuthides Li 3 REBi 2 (RE=Ce, Pr, Sm, Gd) were synthesized from the elements in sealed niobium ampoules and characterized by powder X-ray diffraction. They crystallize with the Li 3 LaSb 2 -type structure, space group P3̅m1

La 3 Ir 2 is formed upon reaction of the elements at 1273 K in a sealed silica ampoule. The structure was refined from single-crystal X-ray diffractometer data: Er 3 Ni 2 -type structure, R3̅, a=895.26(2), c=1713:01(5) pm, wR=0.0578, 766 F 2 values, 25 variables. The structure is composed of two simple basic building units: slightly distorted La1@La3 6 La2 2 cubes resembling the tungsten structure and Ir 2 @La1 1 La2 2 La3 5 units with an AlB 2 -related coordination (298 pm Ir-Ir in the dumb-bell). Each cube is coordinated by six of the AlB 2 units. The relationship with the U 3 Si 2 -type structure is discussed.