Crystal and molecular structure of β-piperidinopropioamidoxime monochloroacetate and hydrochlorides of its O-benzoylation products

The structures of -piperidinopropioamidoxime monochloroacetate and O-benzoyl- and O-para-toluyl--piperidinopropioamidoxime hydrochlorides have been determined. The geometry of these compounds is analyzed. The N-O bond is in the syn-planar position in -piperidinopropioamidoxime monochloroacetate, but adopts an anti-orientation relative to the C(2)-C(3) bond of the propioamidoxime fragment in the other two compounds. In -piperidinopropioamidoxime monochloroacetate crystals, the cation-anion pairs are joined by intermolecular hydrogen bonds into chains; the latter are linked by van der Waals contacts. The crystals of the O-benzoyl- and O-para-toluyl--piperidinopropioamidoxime hydrochlorides are characterized by the same system of hydrogen bonds; the cations and anions are linked by hydrogen bonds into layers, and the latter make van der Waals contacts in the structure.Original Russian Text Copyright © 2004 by K. M. Beketov, J. T. Welch, P. Toskano, L. A. Kayukova, A. L. Akhelova, and K. D. PralievTranslated from Zhurnal Strukturnoi Khimii, Vol. 45, No. 3, pp. 535–543, May–June 2004.     

Crystal structure of monohydrate and anhydrous β-alaninium tetrafluoroantimonates(III)

Novel complexes of Sb(III) fluorides with cation of -aminopropionic acid (-alanine), (NH₃(CH₂)₂COOH)SbF₄ H₂O (I) and (NH₃(CH₂)₂COOH)SbF₄ (II), are synthesized and their crystal structures are determined. Crystals I and II are monoclinic with a = 12.1580(5) , b = 7.4167(4) , c = 10.1540(5) , = 108.222(2)°, Z = 4, space group P2₁/c for (I) and a = 10.483(1) , b = 7.5906(8) , c = 9.4237(9) , = 90.548(2)°, Z = 4, space group P2₁/c for (II). Structures I and II are formed by -alaninium cations (C₃H₈NO₂)⁺ and complex anions [SbF₄] _n ^n– with polymer chain structure. Complex I also contains crystallization water molecules. In the structures of complexes I and II, the -alaninium cations have different conformation, the torsion angles C(1)C(2)C(3)N in these complexes are 174.5° and 77.0°C, respectively.__________Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 4, 2005, pp. 243–247.Original Russian Text Copyright © 2005 by Udovenko, Zemnukhova, Kovaleva, Davidovich.     

Crystal and molecular structure of N-(4-nitrophenyl)-β-alanine--its vibrational spectra and theoretical calculations

The N-(4-nitrophenyl)-β-alanine in crystalline form directly by the addition of 4-nitroaniline to the acrylic acid in aqueous solution has been obtained. The title β-alanine derivative crystallizes in the P2(1)/c space group of monoclinic system with four molecules per unit cell. The X-ray geometry of β-alanine derivative molecule has been compared with those obtained by molecular orbital calculations corresponding to the gas phase. In the crystal the molecules related by an inversion center interact via symmetrically equivalent O-H···O hydrogen bonds with O···O distance of 2.656(2) ? forming a dimeric structure. The dimers of β-alanine derivative weakly interact via N-H···O hydrogen bonds between the H atom of β-amine groups and one of O atom of nitro groups. The room temperature powder vibrational (infrared and Raman) measurements are in accordance with the X-ray analysis. In aqueous solution of 4-nitroaniline and acrylic acid, the double CC bond of vinyl group of acrylic acid breaks as result of 4-nitroaniline addition.     

Amphiphilic conjugates of β-cyclodextrin with acetylsalicylic and 2-(4-isobutylphenyl)propionic acids

New amphiphilic β-cyclodextrin derivatives containing pharmacologically important aromatic and aliphatic monocarboxylic acid fragments at both primary and secondary hydroxy groups were synthesized with the use of palmitic, acetylsalicylic, and 2-(4-isobutylphenyl)propionic acid chlorides. The position of the acyl groups in the carbohydrate fragments of β-cyclodextrin was determined by ¹³C NMR spectroscopy.     

Crystal structure of α-cyanoacrylic acid

An x-ray structural investigation of -cyanoacrylic acid has been carried out (R=0.058 on the basis of 767 reflections). The molecules in the crystal are joined by strong O–H...N hydrogen bonds in zigzag chains along the [101] direction. The relative arrangement of the double bonds of neighboring molecules does not satisfy the conditions for topochemical reactions in crystals of compounds with C=C double bonds, in agreement with the stability of the crystals of -cyanoacrylic acid toward illumination and prolonged exposure to x rays.A. N. Nesmeyanov Institute of Organometallic Compounds, Academy of Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 32, pp. 139–143, March–April, 1991.     

Crystal and molecular structure of nitrophenyl 2,3,4-tri-O-acetyl-β-d-xylopyranosides

Comprehensive structural analyses were performed for o-, m-, and p-nitrophenyl 2,3,4-tri-O-acetyl-β-d-xylopyranosides. Single-crystal X-ray diffraction data were collected and revealed that meta isomer undergoes temperature-dependent polymorph transition (crystal structures of two polymorphs were obtained). This transition was verified by differential scanning calorimetry. The number of molecules in the independent part of the crystal unit cells of the compounds under investigation was in agreement with the number of resonances in solid-state ¹³C and ¹⁵N NMR spectra. The o- and p-nitrophenyl 2,3,4-tri-O-acetyl-β-d-xylopyranosides exist as single polymorph at room temperature, as confirmed by powder X-ray diffraction measurements.     

Crystal and molecular structure of 2,3-benzo-1,4,7,13-tetraoxa-10-selenacyclopentadeca-2-ene

The crystal structure of 2,3-benzo-1,4,7,13-tetraoxa-10-selenacyclopentadeca-2-ene was de-termined,C_(14)H_(20)O_4Se,M_r:331.27,orthorhombic,Pbca,a=18.445(3),b=16.334(4),c9.232(2),V=2781.3 ~3,Z=8,Dx=1.582 Mg m~(-3),λ(Mo K_α)=0.71073 ,μ=26.77 cm~(-1),F(000)=1360,T=297 K,R=0.0329,R_w=0.0438 for 2192 reflections with I>3 σ(I).The crystal structure is closelyrelated to that of benzo-15-crown-5(at 123 K),whereas the molecular geometry of the two coronandsis different according to their torsion angles calculated and the shapes exhibited.     

Crystal and molecular structure of the “asymmetric” ethylenediamine-N,N-di-3-propionic acid monohydrate

A new complexing agent the “asymmetric” ethylenediamine-N,N-di-3-propionic acid (as.EDDP) is obtained. The crystal structure of the new compound is determined by single-crystal X-ray diffraction. C₈H₁₆N₂O₄·H₂O crystals are monoclinic; space group P2₁/c, a = 12.7416(4) Å, b = 6.5470(2) Å, c = 12.1908(4) Å, β = 93.100(1)°, Z = 4, ρ _x = 1.454 mg/m³, and R ₁ (I > 2.0σ(I)) = 0.0326. In the solid form, the as.EDDP molecule has a double betaine structure: The intramolecular hydrogen bonds with the betaine proton of the tertiary nitrogen atom are formed with the participation of one oxygen atom of the carboxyl group of each 3-propionic fragment, which forms two N(1)-H(1N)-bonded six-membered H-cycles. The intermolecular hydrogen bonds are formed between the three hydrogen atoms of the protonated primary nitrogen atom and the oxygen atoms of the 3-propionic fragments of three other as.EDDP molecules. The water molecule participates in the formation of intermolecular hydrogen bonds with the oxygen atom of one carboxyl group of the molecule.     

Synthesis and Chemical Transformations of β-(3,5-DI-tert-butyl-4-hydroxyphenyl)propionic Hydrazide

A method for synthesis of -(3,5-di-tert-butyl-4-hydroxyphenyl)propionic hydrazide. Certain chemical properties of the product were studied. It was found that -(3,5-di-tert-butyl-4-hydroxyphenyl) -(3,5-di-tert-butyl-4-hydroxyphenyl)hydrazide is highly susceptible to oxidation.     

Crystal and molecular structure of an inclusion compound formed between 2′,6′-dimethoxyflavone and perchloric acid. Comparative study with other acid solvates

Crystal determination of a complex between 2,6-dimethoxyflavone and perchloric acid revealed that the inclusion compound contains a water of crystallization that participates in hydrogen bonds connecting the perchloric anion and the carbonyl oxygen of the flavone. The torsion angle between the-benzopyrene and the phenyl rings O(1)C(2)C(1)C(6) is –45, which gives a less twisted molecule than the parent molecule or other inclusion compounds with carboxylic acids. A comparative study with these structures shows that the hydrogen bond forces coplanarity between the-benzopyrone and phenyl rings.     

Crystal and molecular structure of 4(3-acryloyloxy)octyloxy- and 4(3-acryloyloxy)hexyloxy-4′-cyanobiphenyls

The molecular and crystal structures of N≡C-C₆H₄-C₆H₄-O-(CH₂)₈-O-CO-CH=CH₂ (4(3-acryloyloxy)octyloxy-4′-cyanobiphenyl) (I) and N≡C-C₆H₄-C₆H₄-O-(CH₂)₆-O-CO-CH=CH₂ (4(3-acryloyloxy)hexyloxy-4′-cyanobiphenyl) (II) were determined by X-ray diffraction. The structures of I and II are stereotype. The space group of I and II is C2/c, Z = 8; lattice parameters I: a = 34.677(7)?, b = 9.452(2)?, c = 13.004(3) ?, β = 99.30(3)°; II: a = 30.858(6) ?, b = 9.504(2) ?, c = 13.082(2) ?, β = 92.78(3)°. The planar extended molecules I and II are packed in the unit cell to give clearly differentiated aliphatic and aromatic regions throughout the whole crystal. All intermolecular contacts are concentrated in the aromatic region. The molecular packing is very loose but the aromatic areas of I and II fully coincide. The only free parameter of the structure is the length of the aliphatic chain (CH₂)n (n = 8 and 6). According to DSC data, compound I possesses enantiotropic mesomorphism and II possesses monotropic mesomorphism.     

Crystal structure of radical-cation salt β-(DOET)4CuBr4·PhCl

A new radical-cation salt β-(DOET)₄CuBr₄·PhCl (DOET = (1,4-dioxanediyl-2,3-dithio)ethylene-dithiotetrathiafulvalene) is synthesized by electrocrystallization in the dc mode (I = 0.12 μA), and its structure is studied. In the structure of the salt, the DOET radical cations are packed in layers parallel to ab. The average charge on DOET is equal to +0.5. The dioxane rings and ethylene groups of DOET, the tetrahedral CuBr ₄ ^2? -anion, and the chlorobenzene molecules are each disordered over two positions with a 50% probability, and the chlorine atoms of chlorobenzene are disordered over four positions with a 25% probability. The salt has semiconducting properties (E _a = 55 meV).     

Synthesis and structure of complexes of some d metals with 10-(2-benzothiazolylazo)-9-phenanthrole (HL). Crystal and molecular structures of [CdL2] · DMF

The coordination compounds of cadmium(II), zinc(II), nickel(II), cobalt(II), and copper(II) with 10-(2-benzothiazolylazo)-9-phenanthrole (HL) were isolated in the crystalline state and studied. The crystal structure of the cadmium complex [CdL₂] · DMF was determined by X-ray diffraction. The ligand is attached to cadmium in the form of anion functioning as an O,N,N-tridentate chelating ligand; this is accompanied by a change in its isomer form. The Cd configuration is a distorted octahedron.     

Efficient preparation of β-hydroxy aspartic acid and its derivatives

We reported an efficient and practical synthetic route to various properly-protected erythreo-β-OH-Asp compounds, which are key β-branched a-amino acid units in coralmycin A and other peptide natural products.     

Physicochemical studies of the structure of N,N′-dinitrourea and its salts

The properties and behavior of dinitrourea and its potassium and dipotassium salts in different solvents have been studied by IR and UV spectroscopy. In different media, dinitrourea can exist in several tautomeric forms. An XRD study of the potassium and dipotassium salts of dinitrourea revealed a tendency toward equalization of the bond lengths of the C-N⁻-NO₂ fragments compared with those of C-NH-NO₂, which agrees with the results of quantum-chemical calculations.     

Synthesis, characterization and antimicrobial studies of mixed ligand silver(I) complexes of triphenylphosphine and heterocyclic thiones: Crystal structure of bis[{(μ-diazinane-2-thione)(diazinane-2-thione)(triphenylphosphine)silver(I) nitrate}]

Mixed ligand silver(I) complexes of triphenylphosphine and heterocyclic thiones (imidazolidine-2-thione (Imt), diazinane-2-thione (Diaz) and 2-mercaptopyridine (Mpy)) having the general formulae [(Ph₃P)Ag(thione)₂]NO₃ and [(Ph₃P)₂Ag(thione)]NO₃ were prepared and characterized by elemental analysis, IR and NMR (¹H, ¹³C and ³¹P) spectroscopic methods. The crystal structure of one of the complexes, [Ag(Ph₃P)(Diaz)₂]₂(NO₃)₂ (1) was determined by X-ray crystallography. The title complex (1) is dinuclear, having each silver atom coordinated to three thione sulfur atoms of Diaz and to one phosphorus atom of PPh₃ in a nearly tetrahedral environment, with an average P-Ag-S bond angle of 108.5°. The spectral data of the complexes are consistent with sulfur coordination of the thiones to silver(I). Antimicrobial activities of the complexes were evaluated by minimum inhibitory concentrations and the results showed that the complexes exhibit a wide range of activity against two gram-negative bacteria (E. coli, P. aeruginosa) and molds (A. niger, P. citrinum), while the activities were poor against yeasts (C. albicans, S. cerevisiae).     

Biodegradation of β-1,4-linked polyglucuronic acid (cellouronic acid)

Biodegradability of -1,4-linked polyglucuronic acid (cellouronicacid), which was prepared from regenerated cellulose by2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation underaqueous conditions, was examined by enzymatic treatments and incubationtreatments with microorganisms collected from some soil samples. Degradation ofcellouronic acid was traced by size exclusion chromatography (HPSEC) or totalorganic carbon (TOC) of the treated products or solutions, respectively.Cellouronic acid was depolymerized by a commercial crude cellulase anddecreasedin its weight average degree of polymerization from about 1600 to 40 by thecellulase treatment at 20 °C for 40 days. ¹³C-NMRanalysis and liquid chromatography of the treated products showed thathydrolysis-type enzymes present in the crude cellulase as contaminantsprimarilydepolymerized cellouronic acid to give glucuronic acid. When aqueous solutionscontaining cellouronic acid were incubated with soil microorganisms for morethan 3 days, the TOC values decreased to less than 20% of the initial value,depending on molecular weight of the cellouronic acid used. The decreasing rateof TOC for cellouronic acid was clearly higher than that ofcarboxymethylcellulose, which is one of the cellulose derivatives havingcarboxymethyl substituents. These results imply that cellouronic acid has bothbiodegradability and metabolizability in the natural environment.     

Crystal and molecular structure of dicopper bis-(3-amino-5-methylisoxazole)tetraacetate [Cu2(μ-OCOCH3)2L2]

It was established by X-ray diffraction analysis that in the dimer complex of 3-amino-5-methylisoxazole (L) [ Cu₂(μ-OCOCH₃)₄L₂ ] the coordination bond is localized at the endocyclic pyridine type N atom. Arguments are given against other possible types of coordination in aminoisoxazole complexes conjectured from IR spectroscopy data in a number of publications. The dimer structure of the complex agrees with antiferromagnetic data (2J = -280 cm^-1 ). Translated fromZhurnal Strukturnoi Khimii, Vol. 41, No. 3, pp. 572-580, May–June, 2000.     

Crystal structure and properties of (Z)-N′-((E)-2-(hydroxyimino)-1-phenylethylidene) isonicotinohydrazide

Compound I contains in its molecule pyridyl, monoxime and hydrazone functions. A non-merohedral twin crystal of the compound with two reciprocal lattices differently oriented and giving rise to double diffraction spot sets with the 0.5:0.5 ratio of the twin components was studied. The hydrazone and oxime units are approximately planar. The dihedral angles between this plane and the planes of the pyridine and phenyl rings are 30.79(19)° and 18.43(13)°, respectively. Both the oxime and hydrazone units in I have an E configuration. The molecules of I are linked via C-H⋯O and O-H⋯N hydrogen bonds forming a 3D framework. The compound was also characterized by IR, ¹H NMR and elemental analyses.