scholarly journals Structural Reassignment of Koetjapic Acid following X-ray Crystallography and NMR Spectroscopy

2017 ◽  
Vol 12 (7) ◽  
pp. 1934578X1701200 ◽  
Author(s):  
Saifullah Abubakar ◽  
Vikneswaran Murugaiyah ◽  
Chin-Hoe Teh ◽  
Kit-Lam Chan
Keyword(s):  
Spectroscopic Data ◽  
Strong Support ◽  
Chair Conformation ◽  
Unit Cell Parameters ◽  
Orthorhombic Crystal ◽  
Dioic Acid ◽  
X Ray ◽  
Cell Parameters ◽  
X Ray Crystallography ◽  
First Time

The crystal structure and absolute configuration of koetjapic acid were unambiguously reassigned by X-ray crystallography with strong support from NMR spectroscopic data. The acid contained 9 quaternary carbon atoms existing as an orthorhombic crystal with a space group of P21 21 21 and unit cell parameters of a = 7.6641(2), b = 14.6844(4) and c = 23.9316(6). Ring A adopted a chair conformation, ring B has an envelope conformation, whilst ring C assumed a half-chair and D displayed a chair conformation. The absolute configurations at C1 ( R), C5 ( R), C7 ( S), C10 ( S), C13 ( R), C14 ( R), C17 ( S) and C18 ( S) were assigned for the first time. The X-ray crystal of koetjapic acid was therefore reassigned as 3,4-seco-olean-4(23),12-diene-3,30-dioic acid. A plausible biogenetic synthetic pathway for compound 1 is also proposed.

Mononuclear and Binuclear Complexes of Platinum(0) Containing (Alkynyl)phenylsilanes

1999 ◽  
Vol 52 (1) ◽  
pp. 51 ◽  
Author(s):  
Martin A. Bennett ◽  
Christopher J. Cobley ◽  
David C. R. Hockless ◽  
Thomas Klettke
Keyword(s):  
Spectroscopic Data ◽  
Chair Conformation ◽  
Membered Ring ◽  
Binuclear Complexes ◽  
Nickel Compound ◽  
X Ray ◽  
X Ray Crystallography

Reaction of bis(cycloocta-1,5-diene)platinum(0) with the (alkynyl)phenylsilanes Ph3SiC2But, Ph2Si(C2But)2 and PhSi(C2But)3 gives, respectively, [Pt (Ph3SiC2But)2] (1b), [Pt {Ph2Si(C2But)}]2 (2b), and [Pt {PhSi(C2But)3}]2 (4b), which contain zerovalent platinum atoms coordinated by two alkyne units. Spectroscopic data indicate that (2b) and (4b) contain two PtC4 and two SiC4 tetrahedra joined at the corners. X-Ray crystallography shows that complex (4b) is isostructural and isomorphous with the known nickel analogue, two of the alkyne units being uncoordinated; the central eight-membered ring comprising two silicon, four alkyne carbon and two platinum atoms has an approximate chair conformation. In contrast, the monomer (1b) is isostructural but not isomorphous with the analogous nickel compound (1a); in the crystal there is evidence for a weak intramolecular phenyl-phenyl interaction.

scholarly journals Sesquiterpene Lactones from Inula oculus-christi

2010 ◽  
Vol 5 (4) ◽  
pp. 1934578X1000500 ◽  
Author(s):  
Mahmoud Mosaddegh ◽  
Maryam Hamzeloo Moghadam ◽  
Saeedeh Ghafari ◽  
Farzaneh Naghibi ◽  
Seyed Nasser Ostad ◽  
...  
Keyword(s):  
Cytotoxic Activity ◽  
Crystal Structures ◽  
Spectroscopic Data ◽  
Sesquiterpene Lactones ◽  
X Ray ◽  
X Ray Crystallography ◽  
First Time

Inula oculus-christi L. (Compositae) extract was chromatographed and three sesquiterpene lactones ergolide, gaillardin and pulchellin C were isolated. The structures of these compounds were determined by analysis of their spectroscopic data, and their crystal structures were defined using X-ray crystallography; the isolation of ergolide and pulchellin C is reported for the first time from this species. These three compounds were evaluated for their in vitro cytotoxic activity against MDBK, MCF7 and WEHI164 cells; ergolide and gaillardin exhibited lower and significantly different IC50 values compared with pulchellin C ( p<0.001).

scholarly journals Synthesis and Crystal Structure of Unexpected (1S,4R,5R,6S)-4-Cyano-2,2,6-trimethyl-3-azabicyclo[3.3.1]nonan-6-yl Acetate

2017 ◽  
Vol 70 (12) ◽  
pp. 1269
Author(s):  
Steven Gareth Williams ◽  
Mohan Bhadbhade ◽  
Roger Bishop ◽  
Alison Thavary Ung
Keyword(s):  
Crystal Structure ◽  
Mass Spectrometry ◽  
High Resolution Mass Spectrometry ◽  
Unit Cell Parameters ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Cell Parameters ◽  
X Ray Crystallography ◽  
Ir And Nmr Spectroscopy ◽  
Resolution Mass

The reaction of (–)-β-pinene with KCN under a mild bridged Ritter reaction gave (1S,5R,6S)-2,2,6-trimethyl-3-aza-bicyclo[3.3.1]non-3-en-6-yl acetate that subsequently reacted to provide an unexpected (1S,4R,5R,6S)-4-cyano-2,2,6-trimethyl-3-azabicyclo[3.3.1]nonane-6-yl acetate. The structure of the compound was determined by high-resolution mass spectrometry, and IR and NMR spectroscopy and confirmed by single crystal X-ray crystallography. The compound crystallises in the monoclinic P21 space group, with unit cell parameters a 8.6120 (17), b 7.4570 (15), c 11.189 (2) Å, and β 110.16 (3)°.

X-ray powder diffraction analysis of imipenem monohydrate

2012 ◽  
Vol 27 (1) ◽  
pp. 20-24
Author(s):  
F. Needham ◽  
C. E. Crowder ◽  
J. W. Reid ◽  
T. G. Fawcett ◽  
J. Faber
Keyword(s):  
Powder Diffraction ◽  
Diffraction Data ◽  
Unit Cell ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Orthorhombic Crystal ◽  
X Ray ◽  
Cell Parameters ◽  
Pharmaceutical Agent ◽  
Structural Database

An experimental X-ray powder diffraction pattern was produced and analyzed for imipenem monohydrate, an antimicrobial pharmaceutical agent. Although there are no experimental powder patterns in the ICDD PDF-4/Organics Database, there is one powder pattern calculated with single-crystal X-ray diffraction data from the Cambridge Structural Database. Here, we report the refined experimental powder diffraction data for imipenem monohydrate. These data for imipenem monohydrate are consistent with an orthorhombic crystal system having reduced unit-cell parameters of a = 8.2534(3) Å, b = 11.1293(4) Å, and c = 15.4609(6) Å. The resulting unit-cell volume, 1420.15(15) Å3, indicates four formula units per unit cell. Observed peaks are consistent with the P212121 space group.

Mn-bearing eleonorite from Hagendorf South pegmatite, Germany: crystal structure and crystal-chemical relationships with other beraunite-type phosphates

2018 ◽  
Vol 233 (7) ◽  
pp. 469-477
Author(s):  
Sergey M. Aksenov ◽  
Nikita V. Chukanov ◽  
Jörg Göttlicher ◽  
Rupert Hochleitner ◽  
Ekaterina S. Zarubina ◽  
...  
Keyword(s):  
Spectroscopic Data ◽  
Secondary Phase ◽  
Crystal Chemical ◽  
Unit Cell Parameters ◽  
Group Mineral ◽  
X Ray ◽  
Cell Parameters ◽  
Octahedral Sites ◽  
Bivalent Cations ◽  
Selective Accumulation

Abstract Mn2+-bearing eleonorite from the Hagendorf South pegmatite situated south of Waidhaus, Upper Palatinate, Bavaria, Germany was study based on single crystal X-ray analysis, Mn and Fe K-edge XANES spectroscopy, as well as IR spectroscopy. According to spectroscopic data, all Mn is bivalent, and all Fe is trivalent. The empirical formula of the mineral is (Mn2+0.58Zn0.13Mg0.04 Fe3+5.24)Σ5.98(PO4)4(H2O,OH,O)11. The monoclinic unit-cell parameters are: a=20.832(3) Å, b=5.1569(3) Å, c=19.200(2) Å, β=93.01(1)°; space group C2/c. The structure was refined to R1=5.20% in anisotropic approximation using 1994 reflections with I>3σ(I). Despite in most beraunite-group minerals M1-site demonstrates selective accumulation of bivalent cations, in Mn-bearing eleonorite Mn2+-cations are disordered between octahedral sites without statistical predominance anywhere; all octahedral M(1–4)-sites are predominantly occupied by Fe3+. M1-site is half-occupied by Fe3+ and contains subordinate Mn2+ and minor Zn2+ and Mg2+. Based on the new data we suppose that Mn-bearing eleonorite was formed as a secondary phase as a result of oxidation of a primary Mn-bearing beraunite-group mineral in with Mn2+ was initially distributed between different M sites.

The crystal structure of veenite

2017 ◽  
Vol 81 (2) ◽  
pp. 355-368 ◽  
Author(s):  
Dan Topa ◽  
Emil Makovicky
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Type Locality ◽  
Double Layers ◽  
Unit Cell Parameters ◽  
Single Crystal Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
First Time ◽  
Pb Substitution

AbstractThe crystal structure of veenite is reported for the first time from a sample from the type locality of Madoc (Ontario, Canada). It has been solved and refined by X-ray single-crystal diffraction on the basis of 4973 observed reflections (with Fo > 4σ(Fo)) with a final R1 = 0.0396. Veenite is monoclinic P21, with unit-cell parameters a = 8.429(2), b = 26.069(5), c = 8.962(2) Å, β = 117.447(2)o. The bulk veenite composition is Ag0.15Pb16.029Sb8.836As6.99S39.95 (for Z = 1) corresponding to N = 4.09 (Me8NS8N + 8, theoretical value is 4.0), with the percentage of the Ag-(As,Sb) substituted end-member only equal to 3.51 mol.%, i.e., a nearly pure Pb-Sb-As sulfosalt. The crystal structure is typical for the N = 4 sartorite homologue, with zig-zag walls of trigonal coordination prisms of Pb which separate slabs of diagonally oriented double-layers populated by Sb and As with partial Pb substitution. Orientation of three-membered crankshaft chains formed by strong (As,Sb) – S bonds on the two surfaces of double-layers differs substantially from that in dufrénoysite, which is a pure Pb-As (N = 4) sulfosalt.

scholarly journals Production and Antifungal Activity of Cordytropolone and (-)-Leptosphaerone A From the Fungus Polycephalomyces nipponicus

2019 ◽  
Vol 14 (5) ◽  
pp. 1934578X1984412 ◽  
Author(s):  
Nilawan Surapong ◽  
Aphidech Sangdee ◽  
Kittipong Chainok ◽  
Stephen G Pyne ◽  
Prapairat Seephonkai
Keyword(s):  
Spectroscopic Data ◽  
High Performance ◽  
Colletotrichum Gloeosporioides ◽  
Culture Broth ◽  
Fusarium Spp ◽  
Dry Extract ◽  
X Ray ◽  
X Ray Crystallography ◽  
Chromatography Analysis ◽  
First Time

Cordytropolone (1) and (−)-leptosphaerone A (2) were isolated from the culture broth of the fungus Polycephalomyces nipponicus. The structures of these two compounds were elucidated by spectroscopic methods and from a comparison of the spectroscopic data with those reported previously. The structure of 1 was confirmed by X-ray crystallography for the first time while the leptosphaerone class (compound 2) was first isolated as its (+)-antipode from the fungus Polycephalomyces ( Cordyceps). The fermentation process was monitored weekly by High performance liquid chromatography analysis for 10 weeks. The predominant compound (1) was produced at ~0.65 mg/mg of dry extract at week 9. Compound 1 exhibited modest antipathogenic fungal activity against Collectrichum musae, Colletotrichum capsici, Colletotrichum gloeosporioides, Fusarium spp. TFPK301, F. spp. FOC1708, and Pestalotia spp. with percentage of mycelial growth inhibition values of 3.74 ± 0.70%, 12.86 ± 1.43%, 0.91 ± 0.56%, 5.46 ± 0.56%, 7.93 ± 0.61%, and 18.75 ± 5.24%, respectively, at 25 μg/mL.

scholarly journals Formation of an unexpected 3,3-diphenyl-3H-indazole through a facile intramolecular [2 + 3] cycloaddition of the diazo intermediate

2019 ◽  
Vol 15 ◽  
pp. 1347-1354
Author(s):  
Andrew T King ◽  
Hugh G Hiscocks ◽  
Lidia Matesic ◽  
Mohan Bhadbhade ◽  
Roger Bishop ◽  
...  
Keyword(s):  
Single Crystal ◽  
Unit Cell ◽  
Unit Cell Parameters ◽  
One Pot ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
X Ray Crystallography ◽  
The One ◽  
Close Contacts

The one-pot reaction of 2,6-bis(diphenylmethyl)-4-methoxyaniline with tert-butylnitrite, BTEAC and DABSO in the presence of CuCl2 provided an unexpected 3H-indazole product 8. The structure of the compound was determined by HRMS, IR, NMR and further confirmed by single crystal X-ray crystallography. The compound crystallises in the triclinic P-1 space group, with unit cell parameters a = 9.2107 (4), b = 10.0413 (5), c = 14.4363 (6) Å, α = 78.183 (2), β = 87.625 (2), γ = 71.975 (2)°. The formation of 8 proceeded through a facile intramolecular [2 + 3] cycloaddition of the diazo intermediate 9. The molecules of 8 are organised by edge–face Ar–H···π, face–face π···π, and bifurcated OCH2–H···N interactions. In addition to these, there are Ar–H···H–Ar close contacts, (edge–edge and surrounding inversion centres) arranged as infinite tapes along the a direction.

scholarly journals Structures of ruthenium-modified Pseudomonas aeruginosa azurin and [Ru(2,2′-bipyridine)2(imidazole)2]SO4·10H2O

1999 ◽  
Vol 55 (2) ◽  
pp. 379-385 ◽  
Author(s):  
Salem Faham ◽  
Michael W. Day ◽  
William B. Connick ◽  
Brian R. Crane ◽  
Angel J. Di Bilio ◽  
...  
Keyword(s):  
Monoclinic Space Group ◽  
Native Protein ◽  
Unit Cell Parameters ◽  
Space Group ◽  
X Ray ◽  
Cell Parameters ◽  
X Ray Crystallography ◽  
Peg 4000 ◽  
Dark Green ◽  
Atomic Coordinates

The crystal structure of Ru(2,2′-bipyridine)2(imidazole)(His83)azurin (RuAz) has been determined to 2.3 Å resolution by X-ray crystallography. The spectroscopic and thermodynamic properties of both the native protein and [Ru(2,2′-bipyridine)2(imidazole)2]2+ are maintained in the modified protein. Dark-green RuAz crystals grown from PEG 4000, LiNO3, CuCl2 and Tris buffer are monoclinic, belong to the space group C2 and have cell parameters a = 100.6, b = 35.4, c = 74.7 Å and β =  106.5°. In addition, [Ru(2,2′-bipyridine)2(imidazole)2]SO4·10H2O was synthesized, crystallized and structurally characterized by X-ray crystallography. Red–brown crystals of this complex are monoclinic, space group P21/n, unit-cell parameters a = 13.230 (2), b = 18.197 (4), c = 16.126 (4) Å, β = 108.65 (2)°. Stereochemical parameters for the refinement of Ru(2,2′-bipyridine)2(imidazole)(His83) were taken from the atomic coordinates of [Ru(2,2′-bipyridine)2(imidazole)2]2+. The structure of RuAz confirms that His83 is the only site of chemical modification and that the native azurin structure is not perturbed significantly by the ruthenium label.

Synthesis and Characterization of A2CaCuO5(A=Nd, Sm)

1998 ◽  
Vol 12 (11) ◽  
pp. 427-431
Author(s):  
K. Jeyabalan ◽  
L. K. Kaliyaperumal ◽  
A. Sekar ◽  
J. Srinivas
Keyword(s):  
Diffraction Analysis ◽  
Unit Cell ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
Unit Cell Parameters ◽  
Orthorhombic Crystal ◽  
X Ray ◽  
Cell Parameters

Synthesis and characterization of A 2 CaCuO 5( A=Nd, Sm ) system is reported. Powder X-ray diffraction analysis shows that the compounds crystallizes in an orthorhombic crystal systems and the unit cell parameters are found to be a=6.399(9)Å, b=7.218(8) Å and c=12.167(17) Å for Nd 2 CaCuO 5 and a=5.872(8) Å, b=7.457(3) Å and c=12.682(18) Å for Sm 2 CaCuO 5.

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