Crystal structures and spectroscopic studies of ternary compounds of Ni(II) with ethylenediamine and 5'GMP and 5'IMP

Two metal complexes [Ni(en)5'GMPH)2(H2O)2] (en).6.5H2O and [Ni(en)(5'IMPH)2(H2O)2].13H2O have been synthesized in the form of suitable crystals for x-ray crystallography (en = ethylenediamine, 5'GMP = guanosine 5'-monophosphate, 5'IMP = inosine 5'-monophosphate). The 5'GMP complex crystallizes in a monoclinic space group P21 (Z = 4) with a = 12.317(2), b = 28.417(4), c = 12.290(2)A, beta (deg) = 89.59(2). The 5'IMP complex is tetragonal, space group P4122 (Z = 4), with a = 12.119(3), b = 12.119(3), c = 28.560(4)A, beta (deg) = 90.0. The crystal structures of both complexes were refined from diffractometer data to conventional R values of 0.073 for the 5'GMP compound (5,284 observed reflections, 1,322 variables) and 0.030 for the 5'-IMP compound (1,529 observed reflections, 296 variables). In both structures, the Ni(II) is surrounded by two water molecules, one chelate ethylenediamine, and two nucleotide molecules. The synthesis was carried out from Ni(en)2Cl2.0.5H2O and the nucleotide in water medium. The dimer structure of the initial complex is broken, and one ethylenediamine is substituted by two molecules of the nucleotide with the N(7) of the purine ring in cis-position. Differences between both structures are largely due to retention in the structure or loss of the en molecule substituted and to the intermolecular hydrogen bonds of the en molecule coordinated. A third complex of composition [Ni(en)(5'IMPH)2(H2O)2] (en).6H2O similar to the 5'GMP complex has been obtained in the form of blue crystals, but unfortunately its crystal structure failed to be refined. This complex is isostructural with the monoclinic one.     

Crystal structure of lactitol (4-O-beta-D-galactopyranosyl-D-glucitol) trihydrate.

Lactitol trihydrate, C12H24O11.3H2O, crystallises in the orthorhombic space group, P2(1)2(1)2(1) with cell dimensions a = 8.306(2), b = 10.163(1), c = 21.321(1) A, and V = 1799.8(5) A3; Z = 4, Dx = 1.47 Mg m-3, lambda(Cu-K alpha) = 1.54178 A, mu = 1.14 mm-1, F(000) = 856, and T = 23 degrees. There are one intra- and thirteen inter-molecular hydrogen bonds in the structure. The bond lengths and angles agree well with the mean values of related structures. The galactopyranosyl ring has a chair conformation.     

Synthesis and structural characterization of rhenium(I) tricarbonyl complexes with the bidentate ligands o-(diphenylphosphino)benzaldehyde (P∩O) and o-[(diphenylphosphino)benzylidene]analine (P∩N)

A series of rhenium(I) tricarbonyl complexes with bidentate P,O donor ligand o-(diphenylphosphino)benzaldehyde (P∩O) and its Schiff base P,N donor ligand o-[diphenylphosphino)benzylidene]analine (P∩N) have been synthesized and structurally characterized. All the complexes of the type [ReX(CO)(3)(LL)] (where LL = P∩O, P∩N) reveal a distorted octahedral structure with the three carbonyl ligands arranged in the facial fashion. Crystal data for 1, C(22)H(15)ClO(4)PRe·1/2C(6)H(14): triclinic, P1, a=8.7430(4), b=9.5767(4), c=13.9449(6) ?, α=93.651(1), β=101.265(1), γ=93.048(1); V=1140.20(9) ?(3), Z=2.2, C(22)H(15)BrO(4)Pre: monoclinic, C2/c, a=31.6800(16), b=8.8880(4), c=18.4517(9) ?, β=124.990(1); V=4256.4(4) ?(3), Z=8. 3, C(28)H(20)ClNO(3)Pre: monoclinic, C2/c, a=22.675(4), b=8.803(2), c=28.218(5) ?, β=100.192(3); V=5543.5(16) ?(3), Z=8.4, C(28)H(20)BrNO(3)Pre: monoclinic, C2/c, a=23.035(1), b=8.7561(4), c=28.269(1) ?, β=100.811(1); V=5600.4(5) ?(3), Z=8.     

Crystallization of Bowman-Birk type protease inhibitor (peanut) and its complex with trypsin

Crystallization and preliminary crystallographic study of Bowman-Birk type protease inhibitors, A-I, A-II, and B-III from peanut seeds (Arachis hypogaea), and of the A-II + trypsin complex were carried out. A-II, with 70 amino acid residues, crystallizes in a trigonal system, P3(1)21 (or P3(2)21), a = 71.8, c = 65.9 A, Z = 12 or 18. The A-I crystal is isomorphous with that of A-II, indicating that the N-terminal residues are in a disordered state in both crystals. The B-III crystal is monoclinic, C2, a = 119.6, b = 69.6, c = 94.2 A, beta = 115.1 degrees, Z is about 40. The A-II + trypsin complex crystallizes in an orthorhombic system, P2(1)2(1)2(1), a = 55.5, b = 56.0, c = 182.1 A, Z = 4.     

Crystal and molecular structure of the centrosymmetric meso-valinomycin analogue—cyclo (D-Val-D-Hyi-D-Val-L-Hyi-L-Val-D-Hyi-L-Val-L-Hyi-L-Val-D-Hyi-L-Val-L-Hyi) (C60H102N6O18)

The crystal structure of cyclo (D -Val-D -Hyi-D -Val-L -Hyi-L -Val-D -Hyi-L -Val-L -Hyi-L -Val-D -Hyi-L -Val-L -Hyi)-2H₂O has been solved by x-ray direct methods. The crystals (grown from a mixture of octane / CH₂C₁₂) are an orthorhombic, centrosymmetric space group Pbca, cell parameters a = 11.458(2). b = 25.613(3). c = 23.691(3) Å. Z = 4; therefore the molecule lies on a center of inversion in the cell. The atomic coordinates for the C, N, and O atoms were refined in the anisotropic thermal motion approximation (allowing for II-atom contribution to F_cal) to a standard R- factor value of 0.081. In contrast to meso-valinomycin, the analogue under study does not adopt an octahedral cage bracelet conformation. It has an unusual centrosymmetric elongated form with two type II terminal β-bends formed by N? H?C?O 4 → 1 type intramolecular H bonds. Two symmetry-related water molecules reside in the elongated molecular cavity of the centrosymmetric depsipeptide ring. © 1995 John Wiley & Sons, Inc.     

Model complexes with naturally occurring ligands (salicylglycine and imidazol) and the biometals copper and cobalt

Two new complexes [Cu(Imz)(4)Cl(2)][Cu(Imz)(4)Cl] (2)(2-OH-Hip)(2) (1) and [Co(2-OH-Hip)(Imz)(3)].H(2)O (2) (with Imz=Imidazol and 2-OH-Hip=2-hydroxyhippuric acid) were prepared and characterized. The molecular structures and the solution and solid state behavior of the complexes were investigated. Complex 1 crystallizes in the monoclinic space group P2(1)/c with a=16.880(1), b=8.046(1), c=24.683(1) A, beta=107.88(1) degrees, and Z=2, while complex 2 crystallizes in the orthorhombic space group Pbca with a=11.712(2), b=15.741(4), c=22.254(4) A, and Z=8. The [Cu(Imz)(4)Cl(2)][Cu(Imz)(4)Cl](2)(2-OH-Hip)(2) solid consists in two distinct monomeric Cu(II) complexes: one of them is neutral octahedral [Cu(Imz)(4)Cl(2)] and the other, charged square basis pyramida [Cu(Imz)(4)Cl](+). The 2-hydroxyhippuric acid, which here acts as a counter ion, is deprotonated at its carboxylic group. Cobalt(III) ion in [Co(2-OH-Hip)(Imz)(3)].H(2)O is at the center of an octahedral environment, coordinated to three Imidazol ligands and to a triply deprotonated 2-hydroxyhippuric acid molecule acting as a tridentate ligand. Aqueous solution equilibrium of the quaternary system Cu(2+)/2-OH-Hip/Imz/H(+) was studied by potentiometric titrations.     

Thiourea derivatives and their nickel(II) and platinum(II) complexes: antifungal activity

We have synthesized two thiourea derivatives of methyl anthranilate (1, 2) and their complexes with nickel (3) and platinum(II) (4). We have also prepared the complexes of nickel(II) with two benzoylthiourea derivatives (5, 6). The obtained compounds were characterized by elemental analysis, spectroscopic methods (FT-IR, UV-vis, NMR), mass spectrometry and thermal analysis. Compound 1, C(20)H(23)N(3)O(2)S, crystallizes in monoclinic space group P21/n, with Z=4, and unit cell parameters, a=8.8042(4) A, b=7.6608(3) A, c=28.834(2) A, alpha=gamma=90 degrees, beta=90.94(1) degrees. Compound 2, C(20)H(21)N(3)O(3)S, crystallizes in monoclinic space group P21/c, with Z=4, and unit cell parameters, a=7.7345(4) A, b=8.6715(4) A, c=29.113(2) A, alpha=gamma=90 degrees, beta=90.67(1) degrees. Compound 5, C(24)H(30)N(4)NiO(2)S(2), crystallizes in monoclinic space group P21/n, with Z=4, and unit cell parameters, a=10.4317(8) A, b=18.517(2) A, c=13.299(1) A, alpha=gamma=90 degrees, beta=104.53(1) degrees. Compound 6, C(25)H(28)Cl(2)N(4)NiO(4)S(2), crystallizes with a molecule of CH(2)Cl(2) in triclinic space group P-1, with Z=2, and unit cell parameters, a=10.362(1) A, b=11.849(2) A, c=12.536(2) A, alpha=90.04(2) degrees, beta=84.73(1) degrees, gamma=113.43(2) degrees. Compounds 1 and 2 show antifungal activity against the major pathogens responsible for important plant diseases (Botrytis cinerea, Colletotrichum fragariae, Fusarium oxysporum and Phoma betae). The antifungal activity is practically the same for morpholine and ethyl derivatives.     

Molecular structure, bioavailability and bioactivity of [Cu(o-phen)2(cnge)](NO3)2.2H2O and [Cu(o-phen)(cnge)(H2O)(NO3)2] complexes

Two Cu(II) complexes with cyanoguanidine (cnge) and o-phenanthroline, [Cu(o-phen)(2)(cnge)](NO(3))(2).2H(2)O (1) and [Cu(o-phen)(cnge)(H(2)O)(NO(3))(2)] (2), have been synthesized using different experimental techniques and characterized by elemental analyses, FTIR, diffuse and UV-vis spectra and EPR and magnetic moment measurements techniques. The crystal structures of both complexes were solved by X-ray diffraction methods. Complex (1) crystallizes in the monoclinic space group C2/c with a=12.621(5), b=31.968(3), c=15.39(1)A, beta=111.68(4) degrees, and Z=8 and complex (2) in the monoclinic space group P2(1)/n with a=10.245(1), b=13.923(2), c=12.391(2)A, beta=98.07(1) degrees, and Z=4. The environments of the copper(II) center are trigonal bipyramidal (TBP) for [Cu(o-phen)(2)(cnge)](2+) and an elongated octahedron for [Cu(o-phen)(cnge)(H(2)O)(NO(3))(2)]. Solution studies have been performed to determine the species distribution. The superoxide dismutase (SOD) activities of both complexes have also been tested in order to determine if these compounds mimic the enzymatic action of the enzyme SOD that protects cells against peroxide radicals.     

Parallel and antiparallel aggregation of alpha-helices. Crystal structures of two apolar decapeptides X-Trp-Ile-Ala-Aib-Ile-Val-Aib-Leu-Aib-Pro-OMe (X = Boc, Ac)

An apolar helical decapeptide with different end groups, Boc- or Ac-, crystallizes in a completely parallel fashion for the Boc-analog and in an antiparallel fashion for the Ac-analog. In both crystals, the packing motif consists of rows of parallel molecules. In the Boc-crystals, adjacent rows assemble with the helix axes pointed in the same direction. In the Ac-crystals, adjacent rows assemble with the helix axes pointed in opposite directions. The conformations of the molecules in both crystals are quite similar, predominantly alpha-helical, except for the tryptophanyl side chain where chi 1 congruent to 60 degrees in the Boc- analog and congruent to 180 degrees in the Ac-analog. As a result, there is one lateral hydrogen bond between helices, N(1 epsilon)...O(7), in the Ac-analog. The structures do not provide a ready rationalization of packing preference in terms of side-chain interactions and do not support a major role for helix dipole interactions in determining helix orientation in crystals. The crystal parameters are as follow. Boc-analog: C60H97N11O13.C3H7OH, space group Pl with a = 10.250(3) A, b = 12.451(4) A, c = 15.077(6) A, alpha = 96.55(3) degrees, beta = 92.31(3) degrees, gamma = 106.37(3) degrees, Z = 1, R = 5.5% for 5581 data ([F] greater than 3.0 sigma(F)), resolution 0.89 A. Ac-analog: C57H91N11O12, space group P2(1) with a = 9.965(1) A, b = 19.707(3) A, c = 16.648(3) A, beta = 94.08(1), Z = 2, R = 7.2% for 2530 data ([F] greater than 3.0 sigma(F)), resolution 1.00 A.     

Systematic studies on pH-dependent transformations of dinuclear vanadium(V)-citrate complexes in aqueous solutions. A perspective relevance to aqueous vanadium(V)-citrate speciation

Vanadium(V) involvement in interactions with physiological ligands in biological media prompted us to delve into the systematic pH-dependent synthesis, spectroscopic characterization, and perusal of chemical properties of arising aqueous vanadium(V)-citrate species in the requisite system. To this end, facile reactions led to dinuclear complexes (NH(4))(4)[V(2)O(4)(C(6)H(5)O(7))(2)].4H(2)O (1) and (NH(4))(6)[V(2)O(4)(C(6)H(4)O(7))(2)].6H(2)O (2). Complex 1 and 2 were characterized by elemental analysis, FT-IR and X-ray crystallography. Complex 1 crystallizes in the monoclinic space group C2/c with a=16.998(5) A, b=16.768(5) A, c=9.546(3) A, beta=105.22(1) degrees, V=2625(1) A(3), and Z=4. Complex 2 crystallizes in the triclinic space group P1;, with a=9.795(4) A, b=9.942(4) A, c=9.126(3) A, alpha=90.32(1) degrees, beta=111.69(1) degrees, gamma=108.67(1) degrees, V=774.5(5) A(3), and Z=1. The structures of 1 and 2 were consistent with the presence of a V(V)(2)O(2) core, to which citrate ligands of differing protonation state were bound in a coordination mode consistent with past observations. Ultimately, the aqueous pH dependent transformations of a series of three dinuclear complexes, 1, 2 and (NH(4))(2)[V(2)O(4)(C(6)H(6)O(7))(2)].2H(2)O (3), all isolated at pH values from 3 to 7.5, were explored and revealed an important interconnection among all species. Collectively, pH emerged as a determining factor of structural attributes in all three complexes, with the adjoining acid-base chemistry unfolding around the stable V(V)(2)O(2) core. The results point to the participation of all three species in aqueous vanadium(V)-citrate speciation, and may relate the site-specific protonations-deprotonations on the dinuclear complexes to potential biological processes involving vanadium(V) and physiological ligand targets.     

Synthesis,structural characterization and in vitro cytotoxicity of organotin(IV) derivatives of heterocyclic thioamides, 2-mercaptobenzothiazole, 5-chloro-2-mercaptobenzothiazole, 3-methyl-2-mercaptobenzothiazole and 2-mercaptonicotinic acid

Five new organotin(IV) molecules with the heterocyclic thioamides; 2-mercaptobenzothiazole (Hmbzt), 5-chloro-2-mercaptobenzothiazole (Hcmbzt), 3-methyl-2-mercaptobenzothiazole (mmbzt) and 2-mercaptonicotinic acid (H(2)mna) of formulae [(n-C(4)H(9))(2)Sn(mbzt)(2)] (1), [(C(6)H(5))(2)Sn(mbzt)(2)] (2), [(CH(3))(2)Sn(cmbzt)(2)].1.7(H(2)O)] (3), [(n-C(4)H(9))(2)SnCl(2)(mmbzt)(2).(CH(2)Cl(2))] (4) and [[(C(6)H(5))(3)Sn](2)(mna).[(CH(3))(2)CO]] (5) have been synthesized and characterized by elemental analysis, 1H-, 13C-NMR, FT-IR and M?ssbauer spectroscopic techniques. Crystal structures of molecules 1, 3 and 5 have been determined by X-ray diffraction at 173(1) K (1 and 5) and 293(2) K (3). Compound 1 C(22)H(26)N(2)S(4)Sn, is monoclinic, space group C2/c, a=44.018(2), b=8.8864(5), c=12.8633(7) A, beta=104.195(5) degrees, Z=8. Compound 3 is also monoclinic, space group P2(1)/c and a=17.128(2) A, b=17.919(2) A, c=7.3580(10) A, beta=98.290(10) degrees, Z=4. In both molecules 1 and 3, two carbon atoms from aryl groups, two sulfur and two nitrogen atoms from thione ligands form a distorted octahedral geometry around tin(IV) with trans-C(2), cis-N(2), cis-S(2) configurations. Compound 5 C(45)H(39)NO(3)SSn(2) is monoclinic, space group P2(1)/n, a=9.1148(2) A, b=29.2819(6), c=15.5556(4) A, beta=106.2851(9) degrees, Z=4. Complex 5 contains two [(C(6)H(5))(3)Sn(IV)] moieties linked by a double deprotonated 2-mercaptonicotinic acid (H(2)mna). Both tin(IV) ions are five coordinated. This complex is the an example of a pentacoordinated Ph(3)SnXY system with an axial-equatorial arrangement of the phenyl groups at Sn(1) atom. Compounds 1, 3 and 5 were tested for in vitro cytotoxicity against the cancer cell line of sarcoma cells (mesenchymal tissue) from the Wistar rat, polycyclic aromatic hydrocarbons (benzo[a]pyrene) carcinogenesis. Compound 5 exhibits strong cytotoxic activity, while complexes 1 and 3 show less cytotoxic activity.     

Crystal structure of beta-D-psicopyranose

Here, we report the crystal structure of d-psicose, C(6)H(12)O(6), one of the rare sugars. The compound crystallizes as the beta-anomer with rarely observed in pyranose carbohydrate structures trans-gauche orientation of the hydroxymethyl group relative to the pyranosyl ring. The crystal system is orthorhombic, space group P2(1)2(1)2(1), Z=4, with cell dimensions a=7.727(2), b=8.672(2), c=11.123(3)A, V=745.3(3)A(3). The pyranosyl ring adopts chair (2)C(5) conformation. The crystal structure at 100(2)K is stabilized by three-dimensional network of O-Hcdots, three dots, centeredO and C-Hcdots, three dots, centeredO intermolecular hydrogen bonds.     

Synthesis,characterization and antitumor activity of novel octahedral Pt(IV) complexes

Novel platinum(IV) complexes were synthesized having octahedral structure for new antitumor agents. The series of (1,4-butanediamine)Pt(IV) complexes of the type trans,cis-[PtA(2)Cl(2)(1,4-butanediamine)] (A=hydroxo 9, acetato 12, trifluoroacetato 13 as axial ligands) and trans-[PtA(2)(malonate)(1,4-butanediamine)] (A=hydroxo 16, acetato 17, trifluoroacetato 18) were synthesized and characterized by IR, NMR and elemental analysis. The molecular structures of 12, 13 and 18 have been determined by X-ray diffraction methods. The crystals are monoclinic, P2 1/c with a=21.165 (5), b=9.050 (3), c=15.293 (3) A, beta=103.89 (2) degrees and Z=8 for 12, a=10.178 (5), b=12.894 (9), c=12.182 (8) A, beta=91.01 (5) degrees and Z=4 for 13 and a=10.460 (5), b=11.199 (8), c=15.641 (7) A, beta=98.41 (5) degrees, Z=4 for 18. Three crystallographically independent molecules of 12, 13 and 18 have octahedral coordination around Pt(IV) cation. The trans,cis-[PtA(2)Cl(2)(1,4-butanediamine)] were prepared by acetylation or trifluoroacetylation of trans,cis-[Pt(OH)(2)Cl(2)(1,4-butanediamine)]. The trans-[PtA(2)malonate(1,4-butanediamine)] 17 and 18 was prepared by a similar method. The in vitro cytotoxicity of theses Pt(IV) complexes have been evaluated against 12 cancer cell lines assayed by MTS method. The IC(50) values of the compounds 12 and 13 were shown to be lower than those of cisplatin. The in vivo antitumor activity of the Pt(IV) complexes was evaluated using mice bearing L1210 leukemia, B16 melanoma and L1210/cis-DDP cancer animal models. The compound 18 was found to highest activity against cisplatin-resistant cancer cells, L1210/cis-DDP, in vivo.     

Synthesis, structure and spectroscopic properties of two models for the active site of the oxygenated state of cytochrome P450 [corrected

Two dioxygen adducts of thiolato-iron(II) porphyrins, [K(222)][Fe(TPpivP)(SC6HF4)(O2)] 1a and [Na(18c.6)][Fe(TPpivP)(SC6HF4)(O2)] 2 were synthesized by reaction of O2 with five-coordinate, high-spin, cryptated alkali metal thiolato-iron(II) 'picket fence' porphyrinate. They were characterized by visible and infrared spectroscopy: lambda max (log epsilon) = 360 nm (4), 427 nm (4.69), 560 nm (3.69), 610 nm (3.40) for both compounds; v(16O-16O) = 1139 cm-1 in chlorobenzene and fluorobenzene for 1a and 2. Single crystals of composition [K(222)][Fe(TPpivP)(SC6HF4)(O2)].[K(222)](SC6HF4)(C 6H5Cl)(H2O) 1b were obtained by diffusion of pentane/xylene mixtures into chlorobenzene solutions of 1a at -5 degrees C. Single crystals of composition [Na(18c.6)][Fe(TPpivP)(SC6HF4)(O2)] were obtained by slow diffusion of pentane into benzene solutions of 2. Structures of 1b and 2 were studied at 20 degrees C (1b) and -100 degrees C (1b and 2). 1b: space group P2(1)/c (monoclinic), a = 16.806(5) A (1.6806 nm), b = 14.331(4) A (1.4331 nm), c = 52.000(15) A (5.2000 nm), beta = 92.95(2) degrees, V = 12.507 A3 (12.507 nm3), Z = 4, Dcal = 1.28 g.cm-3 (t = 20 degrees C). The final R1 factor was 0.085 for 5238 reflections having I greater than 3 sigma(I). 2: space group P2(1)/c (monoclinic), a = 13.107(3) A (1.3107 nm), b = 27.055(4) A (2.7055 nm), c = 25.029(4) A (2.5029 nm), beta = 96.84(2) degrees, V = 8812 A3 (8.812 nm3), Z = 4, Dcal = 1.18 g.cm-3 (t = -100 degrees C). The final R1 factor was 0.088 for 6587 reflections having I greater than 3 sigma(I). The iron atom is, in both compounds, bonded to the four porphyrinato nitrogens (Np), the sulfur atom of the axial thiolate and one oxygen atom of the axially end-on bonded dioxygen molecule. The average Fe-Np distance found in 1b [1.994(4) A, 0.1994 nm] is not significantly different from that found in 2 [1.993(3) A, 0.1993 nm]. The Fe-S bond length is 2.367(3) A (0.2367 nm) in 1b and 2.365(2) A (0.2365 nm) in 2. The Fe-O1 distances with the oxygen atom of O2 bonded to iron are respectively 1.837(9) A (0.1837 nm) and 1.850(4) A (0.1850 nm). The end-on bonded O2 molecule is disordered in both complexes 1b and 2.(ABSTRACT TRUNCATED AT 400 WORDS)     

Single crystals of a random copolypeptide composed of γ-benzyl l-glutamate and l-phenylalanine

Lamellar single crystals were formed from a random copolypeptide composed of γ-benzyl l-glutamate and l-phenylalanine at the ratio of 4 to 1. The copolypeptide takes the αhelical structure. The crystals were formed by casting dilute solutions at room temperature from a solvent consisting of a 1 to 1 mixture of chloroform and trifluoroacetic acid and were observed by electron microscopy. The average crystal thickness was 670 a in the as-polymerized sample, and 580 a in a fractionated sample. The thickness was decreased by annealing at temperatures above 110 C. A hexagonal form, a group of three orthorhombic forms (group 1), and a group of an orthorhombic form and two monoclinic forms (group II) were observed by electron diffraction. The diversity of the crystal structures is suggested to be caused by a variation in crystallization conditions during evaporation of the solvent. The hexagonal form and the structures of group I are changed into the structures of group II by annealing. The crystal structures other than the hexagonal form indicate on ordered arrangements of side chains in the crystals.     

Molecular conformation prostaglandin A1 monoclinic crystalline polymorph.

The molecular conformation of the monoclinic crystalline polymorph of prostaglandin A1 has been determined by X-ray diffraction techniques. The space group is P21 with a = 13.637(2), b = 7.567(1), c = 10.576(2) A, beta = 107.37(3) degrees; Dc = 1.073 g.cm-3 for Z = 2. The molecular conformation is characterized by the nearly parallel arrangement of the C1-C7 and C13-C20 side chains, with a general flattening of the overall structure when compared with the orthorhombic polymorph. The cyclopentenone moiety assumes a C8 envelope conformation with C8 and O9 displaced +0.29 A and -0.18 A from the C9-C10=C11-C12 plane respectively. Concerted, small varations of the torsion angles, primarily about the C8-C12, C14-C15 and C16-C17 bonds, bring the monoclinic and orthorhombic conformations into coincidence.     

Synthesis and crystal structures of Boc-L-Asn-L-Pro-OBzl.CH3OH and dehydration side product, Boc-beta-cyano-L-alanine-L-Pro-OBzl

Boc-L-Asn-L-Pro-OBzl: C21H29O6N3.CH3OH, Mr = 419.48 + CH3 OH, monoclinic, P2(1), a = 10.049(1), b = 10.399(2), c = 11.702(1) A, beta = 92.50(1)degrees, V = 1221.7(3) A3, dx = 1.14 g.cm-3, Z = 2, CuK alpha (lambda = 1.54178 A), F(000) = 484 (with solvent), 23 degrees, unique reflections (I greater than 3 sigma(I)) = 1745, R = 0.043, Rw = 0.062, S = 1.66. Boc-beta-cyano-L-alanine-L-Pro-OBzl: C21H27O5N3, Mr = 401.46, orthorhombic, P2(1)2(1)2(1), a = 15.741(3), b = 21.060(3), c = 6.496(3) A, V = 2153(1) A3, dx = 1.24 g.cm-3, Z = 4, CuK alpha (lambda = 1.54178 A), F(000) = 856, 23 degrees, unique reflections (I greater than 3 sigma(I)) = 1573, R = 0.055, Rw = 0.078, S = 1.86. The tert.-butyloxycarbonyl (Boc) protected dipeptide benzyl ester (OBzl), Boc-L-Asn-L-Pro-OBzl, prepared from a mixed anhydride reaction using isobutylchloroformate, Boc-L-asparagine, and HCl.L-proline-OBzl, crystallized with one methanol per asymmetric unit in an extended conformation with the Asn-Pro peptide bond trans. Intermolecular hydrogen bonding occurs between the methanol and the Asn side chain and between the peptide backbone and the Asn side chain. A minor impurity due to the dehydration of the Asn side chain to a beta-CNala crystallized with a similar extended conformation and a single intermolecular hydrogen bond.     

Low-temperature (180 K) crystal structures of tetrakis-mu-(niflumato)di(aqua)dicopper(II) N,N-dimethylformamide and N,N-dimethylacetamide solvates, their EPR properties, and anticonvulsant activities of these and other ternary binuclear copper(II)niflumate complexes

Two pseudopolymorphs, solvates, of [Cu(2)(II)(niflumate)(4)(H(2)O)(2)] of unknown structure were obtained following solution of [Cu(2)(II)(niflumate)(4)(H(2)O)(2)] in N,N-dimethylacetamide (DMA) or N,N-dimethylformamide (DMF). Low-temperature crystal structures obtained for these solvates revealed that they were ternary aqua DMA and DMF solvates: [Cu(2)(II)(niflumate)(4)(H(2)O)(2)].4DMA and [Cu(2)(II)(niflumate)(4)(H(2)O)(2)].4DMF. Intermolecular hydrogen bonding interactions account for the formation of these stable DMA and DMF solvates. These pseudopolymorphs contain a centrosymmetric binuclear center with Cu-Cu bond distances ranging from 2.6439(7) to 2.6452(9) A; the coordination sphere of Cu(II) is characterized by one long Cu-O (water) bond length of 2.128(3)-2.135(3) A and four short Cu-O (carboxylate) bonds of 1.949(3)-1.977(3) A. Crystal parameters for the DMA pseudopolymorph: a=10.372(1), b=19.625(2), c=17.967(2) A, beta=97.40(1) degrees , V=3626.8(6) A(3); monoclinic system; space group: P2(1)/a and for the DMF pseudopolymorph: a=10.125(2), b=18.647(3), c=19.616(4) A, alpha=74.38(2)(o), beta=88.18(2)(o), gamma=79.28(2)(o), V=3504(1) A(3); triclinic system; space group: P1. EPR spectra of these solids are identical and show strong antiferromagnetic coupling between the copper atoms, similar to the spectrum obtained for [Cu(2)(II)(niflumate)(4)(DMSO)(2)]. The [Cu(2)(II)(niflumate)(4)(H(2)O)(2)], [Cu(2)(II)(niflumate)(4)(H(2)O)(2)].4DMA, [Cu(2)(II)(niflumate)(4)(H(2)O)(2)].4DMF, [Cu(2)(II)(niflumate)(4)(DMF)(2)], and[Cu(2)(II)(niflumate)(4)(DMSO)(2)] evidenced protection against maximal electroshock-induced seizures and Psychomotor seizures at various times after treatment, consistent with the well known antiinflammatory activities of Cu chelates, but failed to protect against Metrazol-induced seizures while evidencing some Rotorod Toxicity consistent with a mechanism of action involving sedative activity.     

Enantiomerically pure quaternary ammonium salts with a chiral alkyl chain N(CH3)(n-C3H7)2(sec-C4H9)I: synthesis and physical studies

A pair of enantiomerically pure quaternary ammonium salts with a chiral side chain, methyl-(R)-(1-methylpropyl)di(n-propyl)ammonium iodide 1 and methyl-(S)-(1-methylpropyl)di(n-propyl)ammonium iodide 2, and the related racemate, methyl-(rac)-(1-methylpropyl)di(n-propyl)ammonium iodide 3, were synthesized through a reductive alkylation procedure, starting from enantiomerically pure and, also, racemic forms of (rac)-(1-methylpropyl)amine. A spectroscopic chiroptical signature in solution was provided by the Raman optical activity spectra of compounds 1 and 2. The crystallographic structures of 1, 2, and 3 were examined by single crystal X-ray diffraction. 1 crystallizes in the tetragonal space group P4(3)2(1)2 (no. 96), a = b = 12.826 (2) A, c = 17.730 (2) A, V = 2916.9 (5) A(3), Z = 8, Flack coefficient 0.04 (2). 2 crystallizes in the tetragonal space group P4(1)2(1)2 (no. 92), a = b = 12.842 (1) A, c = 17.749 (2) A, V = 2927.0 (5) A(3), Z = 8, Flack coefficient 0.05 (2). The crystal structures and space groups for 1 and 2 are enantiomorphs and the crystallographic investigation confirmed the absolute configuration of the stereocenter in both compounds. 3 crystallizes in the monoclinic space group P2(1)/n(no. 14), a = 8.178 (1) A, b = 14.309 (2) A, c = 12.328 (2) A, beta = 96.811 (6) degrees, V = 1432.4 (2) A(3), Z = 4.     

Molecular structure, stereochemistry and interactions of steffimycin B, and DNA binding anthracycline antibiotic

The crystal and molecular structure of anthracycline antibiotic steffimycin B(C29H32O13) has been determined by X-ray diffraction and the stereochemistry revealed. The orthorhombic crystals belong to space group P2(1)2(1)2(1), with the dimensions; a = 8.253 (2), b = 8.198 (2), c = 40.850 (8) A and Z = 4. Intensity data were collected for 2518 independent reflections. The structure was solved by direct methods and refined to an R value of 0.066 for 1410 reflections. The configuration in ring A is 7R,8S,9S. Ring A adopts half chair conformation, while the sugar ring has the regular chair conformation. The molecule most probably binds to double helical DNA through intercalation and hydrogen bonding.