Crystal Structures of Dipeptides Derived from the β-Amino Acids (1R,2S)-2-Aminocyclopentanecarboxylic Acid and (1S,2R,3S)-2-Amino-3-methylcyclopentanecarboxylic Acid

Abstract  

Crystals of the dimeric β-peptides 13 and 20, derived from (1R,2S)-2-aminocyclopentanecarboxylic acid and (1S,2R,3S)-2-amino-3-methylcyclopentanecarboxylic acid, respectively, were synthesised and studied by X-ray diffraction in order to establish their solid state secondary structural characteristics. Compound 13 crystallises in the monoclinic space group P 2 ₁ with cell parameters of a = 5.2682(1) ?, b = 9.1211(2) ?, c = 22.4467(6) ?, β = 91.3855(9)°, V = 1078.29(4) ?³ and Z = 2. Compound 20 crystallizes in the orthorhombic space group P 2 ₁ 2 ₁ 2 ₁ with cell parameters of a = 5.0968(1) ?, b = 11.5546(2) ?, c = 43.5414(8) ?, V = 2564.22(8) ?³ and Z = 4. In both cases adjacent molecules are linked by a series of N–H···O=C hydrogen bonds to form β-sheet like structures.     

Stereospecific Ligands and Their Complexes. III. Oxalato and Malonato-(ethylenediamine- N , N ′-di- S , S -2-propionato)-Chromate(III) Complexes. Crystal Structure of the Δ-(–)589- s - cis -K[Cr( S , S -eddp)(ox)]?·?0.5H2O

Abstract  The s-cis-[Cr(S,S-eddp)L]⁻ complexes (S,S-eddp = S,S-ethylenediamine-N,N′-di-2-propionate ion; L = oxalate or malonate ions) were prepared. The complexes were purified by ion-exchange chromatography. The geometry of the complexes has been supposed on the basis of the electronic absorption spectra, and the absolute configurations of the isolated s-cis-[Cr(S,S-eddp)L]⁻ complexes have been predicted on the basis of their circular dichroism (CD) spectra and confirmed by X-ray analysis of the crystal structure of the Δ-(–)₅₈₉-s-cis-K[Cr(S,S-eddp)(ox)] 0.5H₂O complex. Index Abstract  The title compound, s-cis-potassium-(ethylenediamine-N,N’-di-S,S-2-propionato) (oxalato)chromate(III) semihydrate was synthesized by passing the corresponding sodium salt through cation exchange-resin Merck I in potassium form and its crystal structure determined. Single crystal X-ray diffraction analysis reveals s-cis geometry of the complex cation. For Part II see Glodjović VV, Trifunović SR (2008) J Serb Chem Soc 73:541.     

Synthesis, Characterization, and Crystal Structures of 3-bromo-N′-(2-methoxybenzylidene)benzohydrazide and N′-(2-methoxybenzylidene)-3,4-methylenedioxybenzohydrazide

Abstract  

Two new hydrazone compounds, 3-bromo-N′-(2-methoxybenzylidene)benzohydrazide (1) and N′-(2-methoxybenzylidene)-3,4-methylenedioxybenzohydrazide (2), have been synthesized and characterized by elemental analysis, IR, and single crystal X-ray diffractions. Compound (1) crystallizes in the triclinic space group P1 with unit cell dimensions a = 8.4088(5) ?, b = 8.5398(5) ?, c = 10.6572(6) ?, α = 90.356(3)°, β = 102.868(3)°, γ = 97.987(3)°, V = 738.28(7) Ǻ³, Z = 2, R ₁ = 0.0406, and wR ₂ = 0.0804. Compound (2) crystallizes in the tetragonal space group P4₁ with unit cell dimensions a = b = 9.792(4) ?, c = 15.788(6) ?, V = 1513.8(10) Ǻ³, Z = 4, R ₁ = 0.0415, and wR ₂ = 0.0818. The molecules of both compounds display E configurations with respect to the C=N double bonds. In the crystal structure of (1), molecules are linked through N–H···O hydrogen bonds, forming chains running along the b axis. In the crystal structure of (2), molecules are linked through N–H···O hydrogen bonds, forming chains running along the c axis.     

Crystal structure of 2,2,3-trimethyl-3-(2′,4′,5′-tricyanophenyl) cyclopentyl-1-acetic acid, methyl ester, C20H21N3O2

The title compound crystallizes in space group P2₁/n, with a = 14.600(2), b = 7.091(2), c = 18.211(5) Å, and = 103.67(2)°. Owing to the centric space group, both C(1) and C(3) chiral centers are either R or S. The acetate group is equatorial, the H(1) and the methyl group at C(3) are axial and reciprocally trans.     

Synthesis and crystal structure of 1-(1′,3′-dimethyl-5′-chloropyrazol-4′-carbonyl′-3-(2′-chlorophenyl)-5-amino-4-cyanopyrazole

The title compound 1-(1,3-dimethyl-5-chloropyrazol-4-carbonyl)-3-(2-chlorophenyl)-5-amino-4-cyanopyrazole (C₁₆H₁₂Cl₂N₆O) has been synthesized and characterized by X-ray diffraction: Triclinic, space group P1, with a = 8.6712(8) Å, b = 9.5091(10) Å, c = 11.2170(11) Å = 71.531(2)°, = 84.683(2)°, = 74.099(2)° Z = 2; V = 843.7(14) ų. C(10), O(1), C(11), and N(2) atoms are coplanar with the average deviation of 0.0071 Å, which form 11.03° and 43.93° dihedral angles with pyrazole planes (I) and (II), respectively.     

Synthesis and Structure of cis-Dioxo(3-Methoxysalicylaldehyde 4-Methylthiosemicarbazonato-N,O,S)(γ-Picoline-N)Molybdenum(VI)

Abstract  Red crystals of cis-dioxo(3-methoxysalicylaldehyde 4-methylthiosemicarbazonato-N,O,S)(γ-picoline-N)molybdenum(VI), [MoO₂L(γ-pic)], [L²⁻=CH₃OC₆H₄(O)CH=NN=C(S)NHCH₃, 3-methoxysalicylaldehyde 4-methylthiosemicarbazonato] were prepared by the reaction of [MoO₂L] _n with γ-picoline in dry methanol. The title compound crystallized in the monoclinic space group P2₁/n, a = 6.7984(7) ?, b = 15.9760(12) ?, c = 17.1466(14) ?, β = 93.613(8)°, V = 1858.6(3) ?³, Z = 4. The coordination geometry around the molybdenum center is distorted octahedral with the tridentate thiosemicarbazonato ligand (L²⁻) bonded meridionally to the [MoO₂]²⁺ core. The sixth coordination site is occupied by a weakly bound γ-picoline molecule. The adjacent molecules are joined by the N–H···O hydrogen bonds between their amino and methoxy groups thus forming infinite molecular chains. The three-dimensional solid-state structure is achieved by the additional C–H···O, C–H···π and van der Waals interactions. Graphical Abstract  In the title compound, [MoO₂L(γ-pic)], the tridentate thiosemicarbazonato ligand (L²⁻) is meridionally bound to the [MoO₂]²⁺ core, while a molecule of γ-picoline completes the distorted octahedral coordination around the metal atom.      

Synthesis and Structures of Two Functionalized Isobenzofurans: (3aR,7aR,4S,5S)-1,3,3a,4,5,7a-Hexahydro-5-methyl-3-oxoisobenzofuran-4-carboxylic acid and (3aα,4β,7β,7aα)-4-[(Acetyloxy)methyl]-3a,4,7,7a-tetrahydro-7-methyl-1,3-isobenzofurandione

Abstract  

The title compounds, C₁₀H₁₂O₄ and C₁₂H₁₄O₅, were prepared as part of an ongoing study to explore the practical aspects of solventless reaction methods. As confirmed by the crystal structures, treatment of maleic anhydride with (2E,4E)-hexa-2,4-dien-1-ol or its acetate counterpart resulted in cis bicyclo [4.3.0] molecular frameworks. The racemic product derived from the dienol synthon crystallized in chiral space group P2₁2₁2₁ via a pasteurian resolution process with molecules organized by carboxyl⋯carboxyl and C–H⋯O contacts. The acetate derivative crystallizes in space group Cc.     

A structural model for a new class of conformationally constrained retinoid: (2Z,4E)-4-[3′,4′-dihydro-1′(2′H)-naphthalene-1′-ylidene]-2-butenoic acid

Racemic (2Z,4E)-4-[3′,4′-dihydro-1′(2′H)-naphthalene-1′-ylidene]-2-butenoic acid (1) is a polyene chain-shortened analog of (9Z)-retinoic acid (3) which uses a tetrahydronaphthyl ring to conformationally constrain the C6-C7 single bond (retinoic acid numbering). The structure of (1) was obtained to determine the effects of the tetrahydronaphthyl ring on the ring to polyene chain conformation as compared to a published crystal structure for (9Z)-retinal (2). The results reveal significant differences between the solid state structures of (1) and (2), particularly for torsion angles about C6, C7 and C8, C9. The title compound crystallizes in the centrosymmetric monoclinic space groupP2₁/n withZ=4. (Cell dimensions:a=10.863(2) Å,b=7.637(2) Å,c=15.781(3) and β=106.11(3)°.) The structure was refined toR=3.88% for those 1132 unique data with |F _o|>6σ(F _o). In the crystal structure, the molecules adopt a hydrogen bonded dimeric structure.     

7-Hydroxy-2-(2,3,4-trimethoxyphenyl)-4H-1-benzopyran-4-one: (7-hydroxy-2′,3′,4′-trimethoxyflavone)

7-Hydroxy-2,3,4-trimethoxyflavone, (C₁₈H₁₆O₆),M _r =328.32 crystallizes in the orthorhombic system, space groupPbna, with the following crystal data:a=8.853(2),b=12.870(2),c=26.293(3)Å,V=2996(1)ų,Z=8, MoK, =0.67 cm^–1,D _c =1.454 g·cm^–3,F(000)=1376,T=294K. The structure was solved by direct-methods and has been refined by full-matrix least-squares methods to a finalR value (F>(F)) of 0.0496. The molecule is not planar, the dihedral angle between the phenyl ring and the fused ring system is 27.3°. There are no intramolecular hydrogen bonds, but intermolecular short hydrogen contacts exist between hydroxyl hydrogen and carbonyl oxygen atoms.     

Crystal structure of 4-phenyl-3,5-dioxacyclohexyl-1, 1′-cyclopentane-2′,3″-(1,5,8,11-tetraoxacyclotridecane)

The structure of the title compound is determined by X-ray diffraction (DAR-UMB diffractometer, θ-θ/2θ scan mode, MoK _α radiation, direct method). The crystal is monoclinic, a = 24.582(6) Å, b = 22.812(8) Å, c = 8.647(3) Å, γ = 60.64(2)°, ρ _calcd = 1.232 g/cm³ space group A2/a, and Z = 8 for C₂₂H₃₂O₆. The molecule consists of four fragments: 13-crown-4 (A), 1,3-dioxane (B), a five-membered ring (C) acting as a bridge between fragments A and B, and a phenyl ring (D). Introduction of the bulky ring C as a bridge into the molecule results in significant deviations (up to ±0.014 Å) of the ether O atoms from planarity. The conformation of the macrocyclic fragment is [3433] according to the Dale notation. The C—H?O 1,4-interactions, which are energetically favorable occur in the propylene part of 13-crown-4: the C(2)?O(5) and C(4)?O(1) distances are 2.82 Å. The molecules in the structure form planar networks parallel to the xy plane. The intermolecular contacts correspond to the van der Waals interactions.     

Bis(2,6-(2′,6′-diisoproylanil)diformyl-4-chloro-phenolate) nickel(II)

Bis(2,6-(2,6-diisoproylanil)diformyl-4-chloro-phenolate) nickel(II) was prepared by the reaction of 2,6-(2,6-diisoproylanil)diformyl-4-chloro-phenol with nickel chloride. The title complex crystallized in P2₁/c, with cell dimensions a = 9.962(2) Å, b = 12.087(3) Å, c = 24.445(6) Å, and = 97.032(5), giving a volume of 2921.4(13) ų. The bis(2,6-(2,6-diisoproylanil)diformyl-4-chloro-phenolate) nickel(II) adapts an ideal parallelogram, in which the Ni atom is coordinated with two phenolic oxygen atoms [O(1), O(1A)] and two imino nitrogen atoms [N(1), N(1A)].     

Synthesis and crystal structures of cis- and trans-1-(3′-N, N-dimethylthiocarbamoyl-4′-methoxy)-2-(3″, 4″, 5″trimethoxyphenyl) ethene

The combretastatin A-4 analogue cis-1-(3-N,N-dimethylthiocarbamoyl-4-methoxy)-2-(3,4, 5-trimethoxyphenyl) ethene (1) and its trans stereoisomer (2) were synthesized. The molecular structures of these compounds were obtained by single-crystal X-ray diffraction. Crystallization of 1 occurs in the centrosymmetric monoclinic space group C2/c (No. 15) with a = 21.468(5), b = 7.932(1), c = 23.949(3); and = 100.75(1) and Z = 8. Crystallization of 2 occurs in the centrosymmetric monoclinic space group P2₁/n (No. 14) with a = 11.7825(7), b = 11.562(1), c = 14.911(1) and = 93.294(6); and Z = 4. Details of the synthesis and the structural characterization of the title compounds are presented and discussed.     

N,N′-Dihydrogenpiperazonium dichloridobis(dimethylglyoximato-k2N,N′)cobaltate(III) Dihydrate

Abstract  

The title complex: C₄H₁₂N₂[Co(C₄H₇N₂O₂)₂Cl₂]₂·2H₂O, viz., PpH₂[Co(dmgH)₂Cl₂]₂·2H₂O, where, dmgH⁻ = dimethylglyoximate and Pp = piperazine was synthesized and analyzed by single crystal XRD studies. The complex was grown as brown crystals by the slow evaporation method in ethanol. The complex crystallizes as triclinic with the space group p[`1] p\overline{1} and unit cell parameters a = 8.4521 (10) Å, b = 10.0999 (11) Å, c = 10.8952(13) Å; α = 94.066(6)°, β = 106.047(6)° and γ = 100.901(6)°. There are two complex molecules present in the unit cell. The short intra molecular O–H···O hydrogen bonds link the glyoximate moieties in the crystal.     

The crystal and molecular structure of spiro[1-(S)-Br-3-(S)-H-4-(R)-l-(1′ R,2′ S,5′R)-menthyloxy-5-oxo-6-oxa-bicyclo[3.1.0]hexane-2,3′-(R)-(4′-(R)-diphenylmethoxy-5′-l-(1′ R,2′ S,5′ R)-menthyloxy-butyrolactone)]

Crystal structure of C₄₁H₅₃O₇Br has been determined by single-crystal X-ray diffraction. The compound crystalline in the orthorhombic space group P2₁2₁2₁, with a = 11.264(2), b = 12.058(2), c = 29.337(6) Å, Z = 4. The bond angles of cyclopropane moiety in the molecule are approximate to 60° and agree with theoretic values of the internal angles in a cyclopropane, and two chiral menthyloxy groups are located above and under the whole chiral molecule, respectively. The configuration of the pentacyclic lactone is shown as envelope form.     

Synthesis and Crystal Structures of N′-3,5-Dibromo-2-Hydroxybenzylidene)-2-Hydroxy-3-Methylbenzohydrazide and its Oxovanadium(V) Complex [N′-(3,5-Dibromo-2-Oxidobenzylidene-κO)-2-Hydroxy-3-Methylbenzohydrazidato-κ2N′,O](Methanol-κO)(Methanolato-κO)Oxidovanadium(V)

Abstract  

A new hydrazine ligand N′-3,5-dibromo-2-hydroxybenzylidene)-2-hydroxy-3-methylbenzohydrazide (1) and its oxovanadium(V) complex [N′-(3,5-dibromo-2-oxidobenzylidene-κO)-2-hydroxy-3-methylbenzohydrazidato-κ ² N′,O](methanol-κO)(methanolato-κO)oxidovanadium(V) (2), were prepared and were structurally characterized by elemental analysis, IR spectra and single-crystal X-ray diffraction. Compound 1 crystallizes in the triclinic space group P−1, with unit cell dimensions a = 7.813(2) ?, b = 8.748(2), c = 26.071(6) ?, α = 85.763(2)°, β = 81.521(2)°, γ = 89.358(3)°, V = 1757.6(7) ?³, Z = 4, R ₁ = 0.0587, and wR ₂ = 0.1054. Compound 2 crystallizes in the triclinic space group P-1, with unit cell dimensions a = 7.777(3) ?, b = 11.594(3), c = 12.363(3) ?, α = 107.965(3)°, β = 103.190(2)°, γ = 96.656(2)°, V = 1011.3(5) ?³, Z = 2, R ₁ = 0.0634, and wR ₂ = 0.1480. The hydrazine ligand coordinates to the V atom through the phenolic O, imino N, and ethanolic O atoms. The V atom in the complex is in an octahedral coordination, with the three donor atoms of the hydrazine ligand and one methanolato O atom defining the equatorial plane, and with one methanol O and one oxo O atoms occupying the axial positions. The displacement of the V atom from the equatorial plane towards the axial oxo O atom is 0.305(2) ?.     

Molecular structure and absolute configuration of (−)-(1R, 2S, 6R, 7S, 2′S)-5-(2′-hydroxymethylpyrrolidin-1′-yl)-endo-tricyclo[5.2.1.02,6]deca-4,8-dien-3-one

The crystal and molecular structure of (–)-(1R, 2S, 6R, 7S, 2S)-5-(2-hydroxymethyl-pyrrolidin-1-yl)-endo-tricyclo[5.2.1.0^2,6]deca-4,8-dien-3-one is described. Knowing the absolute configuration of the prolinol moiety (S) the X-ray diffraction study established the absolute configuration of the title compound. The structure was refined to R ₁ = 0.0322 for 1237 reflections (with I > 2(I)). Crystal data: C₁₅H₁₉NO₂, monoclinic, space group P2₁, a = 6.0757(4), b = 11.3473(5), c = 9.5114(7)Å, = 104.686(6)°, V = 634.32(7)ų, and Z = 2.     

Synthesis, Crystal Structure of catena-poly [[4,4′-bipyridine-N,N′-bis[(triphenylphosphine)-copper(I)]-pyridine-2-carbaldehyde azine-N,N′:N″,N′″] bis(tetrafluoroboride)]

Abstract  

The title complex [Cu₂(C₁₀H₈N₂)(C₁₂H₁₀N₄)(C₁₈H₁₅)₂(BF₄)₂] _n has been synthesized and characterized by single crystal X-ray analysis. The compound crystallizes in the monoclinic space group P2₁/c with a = 10.450(4) Å, b = 14.027(5) Å, c = 18.950(6) Å, β = 100.459(5)°, V = 2,731.7(16) ų. In the title complex, the cation forms a linear chain, which is bridged by 4,4′-bipyridine and pyridine-2-carbaldehyde azine. The crystallographic asymmetry unit could be expanded polymeric structure using symmetry code: x, 1 + y, z; 1 − x, −y, 1 − z. The Cu(I) atom is coordinated by one P atom of PPh₃ ligand, two N atoms of pyridine-2-carbaldehyde azine ligand and one N atom of 4,4′-bipyridine ligand. There is a crystallographic centre of symmetry at the mid-point of the C–C bond between two pyridine rings of 4,4′-bipyridine.     

Synthesis, Characterization and X-Ray Structure of Bis(O-propyldithiocarbonato-κ2S,S′)bis(4-cyanopyridine-κN)nickel(II)

Abstract  

The [Ni(S₂COCH₂CH₂CH₃)₂(C₆H₄N₂)₂] adduct of 4-cyanopyridine with [Ni(S₂COCH₂CH₂CH₃)₂] was synthesized and characterized by elemental analysis, magnetic susceptibility measurement, IR, electronic spectral data, Thermogravimetric analysis/DTA techniques and X-ray diffraction analysis. The Ni atom in the title complex is octahedrally coordinated within a trans-N₂S₄ donor set, with the Ni atom located on a centre of inversion. The title complex crystallizes in the monoclinic space group P2 ₁ /c with unit cell parameters a = 11.75(4), b = 11.62(3), c = 9.20(2) ?, β = 104.99(3)°. Crystal structure was solved by direct methods and refined by full matrix least squares procedures to a final R-value of 0.0294 for 1895 observed reflections. The packing of layers of molecules is stabilized by weak C–H···N and C–H···π interactions.     

Synthesis and Structural Characterization of Dibromidobis(N,N′-dimethylthiourea-κS)cadmium(II) and Diiodidobis(N,N′-dimethylthiourea-κS)cadmium(II)

Abstract  

Cadmium(II) complexes, dibromidobis(N,N′-dimethylthiourea-S)cadmium(II), [Cd(Dmtu)₂Br₂] (1) and diiodidobis(N,N′-dimethylthiourea-S)cadmium(II), [Cd(Dmtu)₂I₂] (2), have been prepared and their structures have been determined by X-ray crystal structure analysis. Compound 1 crystallized in the monoclinic space group C2/c, and the metal ion is situated on a twofold rotation axis. Compound 2 also crystallized in a monoclinic space group, P2₁/c, but here the molecules have no crystallographic symmetry. In both compounds the cadmium atom is bonded to two halide ions and to two dimethylthiourea molecules through the sulfur atoms in a tetrahedral environment. The molecules are linked via N–H⋯Halide hydrogen bonds to form infinite one-dimensional chains in 1 and infinite two dimensional networks in 2. The complexes were also characterized by IR and NMR spectroscopy and the data are consistent with the structures of the compounds.     

Structural study of nitrovinylindoles: (I) 2-methyl-3-(2′-methyl-2′-nitrovinyl)indole and (II) 3-(2′-nitrovinyl)indole

Compound (I) is 2-methyl-3-(2-methyl-2-nitrovinyl)indole, C₁₂H₁₂N₂O₂,M _r=216.24, monoclinic,P2₁/n,a=16.710(1),b=7.627(1),c=17.646(1) Å,=104.8(1)°,V=2174.7(1) ų,Z=8.D _x=1.321 g cm^–3, MoK, =0.71073 Å,=0.858 cm^–1,F(OOO)=912, room temperature,R=0.061 for 1956 observed reflections. Compound (II) is 3-(2-nitrovinyl)indole, C₁₀H₈N₂O₂,M _r=188.18, monoclinic,P2₁/n,a=10.178(1),b=10.608(1),c=8.411(1) Å,=105.5(2)°,V=875.0(1) ų,Z=4,D _x=1.4284 g cm^–3, CuK, =1.5418 Å,=8.068 cm^–1,F(000)=392, room temperature,R=0.040 for 1330 observed reflections. Compounds (I) and (II) have a similar geometry, the only significant difference lying in the rotation of the nitrovinyl chain. This feature could be responsible for the difference in biological activity. In both compounds, the molecules are associated, forming charge-transfer complexes.