7α-Acetoxydihydronomilin: isolation, spectra, and crystal structure

1978 ◽  
Vol 56 (7) ◽  
pp. 1020-1025 ◽  
Author(s):  
Farid R. Ahmed ◽  
Angs Ng ◽  
Alex G. Fallis
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Least Squares ◽  
Furan Ring ◽  
Lactone Ring ◽  
Direct Method ◽  
Membered Ring ◽  
Intermolecular Hydrogen Bonding ◽  
X Ray ◽  
Twist Boat

Methanol extraction of the ground seeds of Uncaria Gambier Roxb. followed by chromatography afforded a crystalline C30H38O10 terpene. This has been shown by X-ray analysis to be 7α-acetoxydihydronomilin. The crystals are orthorhombic, P212121, a = 13.158(2), b = 17.092(2), c = 12.689(2) Å, Z = 4, dx = 1.300, do = 1.300 g cm−3. The structure has been determined by the direct method and Fourier syntheses, and refined by block-diagonal least-squares to R = 0.042 for 2621 observed reflexions. The molecule contains a seven-membered lactone ring A, three six-membered rings B, C, D, a three-membered ring E, a furan ring F, and two acetate groups. A and B are chair, C is twist-boat, D is 1,3-diplanar, while E and F are planar. The A/B, A/C, C/D junctions are trans, D/E is cis, and F is linked to D by an equatorial C—C bond. The two acetate groups are in axial positions on A and B and are cis to each other. The O atom forming the apex of the three-membered ring is wedged between two H atoms and their parent C atoms at short intramolecular distances O … H = 2.28(2) and 2.28(3), and O … C = 2.623(3) and 2.668(4) Å. No intermolecular hydrogen bonding is indicated.

scholarly journals Exploring the Structural Chemistry of Pyrophosphoramides: N,N′,N″,N‴-Tetraisopropylpyrophosphoramide

Chemistry ◽  
2021 ◽  
Vol 3 (1) ◽  
pp. 149-163
Author(s):  
Duncan Micallef ◽  
Liana Vella-Zarb ◽  
Ulrich Baisch
Keyword(s):  
Crystal Structure ◽  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Hydrogen Bonding ◽  
Nmr Spectroscopy ◽  
Ir Spectroscopy ◽  
Room Temperature ◽  
Intermolecular Hydrogen Bonding ◽  
X Ray Diffraction ◽  
X Ray

N,N′,N″,N‴-Tetraisopropylpyrophosphoramide 1 is a pyrophosphoramide with documented butyrylcholinesterase inhibition, a property shared with the more widely studied octamethylphosphoramide (Schradan). Unlike Schradan, 1 is a solid at room temperature making it one of a few known pyrophosphoramide solids. The crystal structure of 1 was determined by single-crystal X-ray diffraction and compared with that of other previously described solid pyrophosphoramides. The pyrophosphoramide discussed in this study was synthesised by reacting iso-propyl amine with pyrophosphoryl tetrachloride under anhydrous conditions. A unique supramolecular motif was observed when compared with previously published pyrophosphoramide structures having two different intermolecular hydrogen bonding synthons. Furthermore, the potential of a wider variety of supramolecular structures in which similar pyrophosphoramides can crystallise was recognised. Proton (1H) and Phosphorus 31 (31P) Nuclear Magnetic Resonance (NMR) spectroscopy, infrared (IR) spectroscopy, mass spectrometry (MS) were carried out to complete the analysis of the compound.

The molecular and crystal structure of [Pt(diethylenetriamine)(guanosine)](ClO4)2

1979 ◽  
Vol 57 (1) ◽  
pp. 57-61 ◽  
Author(s):  
R. Melanson ◽  
F. D. Rochon
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Least Squares ◽  
Platinum Atom ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
R Factor ◽  
Square Planar ◽  
Coordination Plane

The crystal structure of [Pt(diethylenetriamine)(guanosine)](ClO4)2 has been determined by X-ray diffraction. The crystals are orthorhombic, space group P212121, with a = 12.486(6), b = 13.444(7), c = 14.678(11) Å, and Z = 4. The structure was refined by block-diagonal least-squares analysis to a conventional R factor of 0.050 and a weighted Rw = 0.045.The coordination around the platinum atom is square planar. Guanosine is bonded to platinum through N(7). The purine planar ring makes an angle of 62.7° with the platinum coordination plane. The structure is stabilized by hydrogen bonding.

Synthese, Struktur und thermisches Verhalten von Thiophosphorsäuretriamid SP(NH2)3 [1] / Synthesis, Structure, and Thermal Behaviour of Phosphorothionic Triamide SP(ΝΗ2)3 [1]

1989 ◽  
Vol 44 (8) ◽  
pp. 942-945 ◽  
Author(s):  
Wolfgang Schnick
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Thermal Properties ◽  
Single Crystal ◽  
Melting Temperature ◽  
Intermolecular Hydrogen Bonding ◽  
X Ray ◽  
Hydrogen Bonding Interactions ◽  
Ray Methods ◽  
Single Bonds

Phosphorothionic triamide SP(NH2)3 is obtained by slow addition of SPCl3 dissolved in dry CH2Cl2 to a satured solution of NH3 in CH2Cl2 at —50°C. Ammonium chloride is removed from the resulting precipitate by treatment with HNEt2 followed by extraction with CH2Cl2. Coarse crystalline SP(NH2)3 is obtained after recrystallization from dry methanol. The crystal structure of SP(NH2)3 has been determined by single crystal X-ray methods (Pbca; a = 922.3(1), b = 953.8(1), c = 1058.4(2) pm, Z = 8). In the crystals the molecules show non-crystallographic point symmetry C8. The P—S bond (195.4(1) pm) is slightly longer than in SPCl3. From P—N bond lengths of about 166 pm a significant electrostatic strengthening of the P—N single bonds is assumed. Weak intermolecular hydrogen bonding interactions (N —H · · · N ≥ 329.5 pm; N — H · · · S ≥ 348.3 pm) are observed.Investigation of thermal properties shows a melting temperature of 115°C for SP(NH2)3. According to combined DTA/TG and MS investigations above this temperature the compound decomposes by evolution of H2S and NH3 to yield amorphous phosphorus(V)nitride.

A heterotrimetallic Ni(II)–Dy(III) bis(salamo)-based complex: synthesis, structure and fluorescent property

2018 ◽  
Vol 73 (5) ◽  
pp. 281-288
Author(s):  
Qing Zhao ◽  
Ying-Qi Pan ◽  
Xiao-Yan Li ◽  
Han Zhang ◽  
Wen-Kui Dong
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Supramolecular Structure ◽  
Fluorescence Spectra ◽  
Intermolecular Hydrogen Bonding ◽  
X Ray Diffraction ◽  
X Ray ◽  
Distorted Octahedral ◽  
Tricapped Trigonal Prism ◽  
Elemental Analyses

AbstractA discrete heterotrinuclear complex [{Ni2LDy(OAc)3(CH3OH)}2] · 2CH3OH · 3CH2Cl2, with a naphthalenediol-based acyclic bis(salamo) ligand H4L, has been synthesized and structurally characterized using elemental analyses, IR, UV/Vis and fluorescence spectra and single crystal X-ray diffraction. The crystal structure shows two crystallographically independent but chemically identical molecules (molecules I and II). All the Ni(II) atoms are hexa-coordinated with slightly distorted octahedral geometries. The central Dy atoms are nona-coordinated with slightly distorted tricapped trigonal prism geometries. An infinite 3D supramolecular structure is formed via intermolecular hydrogen bonding and C–H…π interactions.

Synthesis and X-ray Crystal Structure of the Novel Organotin Dication [n-Bu2Sn(H2O)4]2+:  A Lamellar Layered Structure Assisted by Intermolecular Hydrogen Bonding

2002 ◽  
Vol 21 (22) ◽  
pp. 4575-4577 ◽  
Author(s):  
Vadapalli Chandrasekhar ◽  
Ramamoorthy Boomishankar ◽  
Sanjay Singh ◽  
Alexander Steiner ◽  
Stefano Zacchini
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Layered Structure ◽  
Intermolecular Hydrogen Bonding ◽  
The Novel ◽  
X Ray

Dendocarbin A: a sesquiterpene lactone fromDrimys winteri

2014 ◽  
Vol 70 (11) ◽  
pp. 1007-1010 ◽  
Author(s):  
Cristian Paz Robles ◽  
Viviana Burgos ◽  
Sebastián Suarez ◽  
Ricardo Baggio
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Sesquiterpene Lactone ◽  
Natural Compound ◽  
Intermolecular Hydrogen Bonding ◽  
Screw Axis ◽  
Orthorhombic Space Group ◽  
X Ray ◽  
First Time ◽  
Drimys Winteri

The natural compound dendocarbin A, C15H22O3, is a sesquiterpene lactone isolated for the first time fromDrimys winterifor var chilensis. The compound crystallizes in the orthorhombic space groupP212121and its X-ray crystal structure confirmed theS/Rcharacter of the chiral centres at C-5/C-10 and C-9/C-11, respectively. The α-OH group at C-11 was found to be involved in intermolecular hydrogen bonding, defining chains along the <100> 21screw axis.

Crystal structure of zerumbone [(E,E,E)-2,6,9,9-Tetramethylcycloundeca-2,6,10-trien-1-one]

1981 ◽  
Vol 34 (10) ◽  
pp. 2243 ◽  
Author(s):  
SR Hall ◽  
S Nimgirawath ◽  
CL Raston ◽  
A Sittatrakul ◽  
S Thadaniti ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Membered Ring ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Zingiber Zerumbet ◽  
Space Group ◽  
X Ray ◽  
Considerable Distortion

The crystal structure of zerumbone, C15H22O, extracted from the rhizomes of Zingiber zerumbet Smith, has been determined by single-crystal X-ray diffraction at 295(1) K and refined by least squares to a residual of 0.051 for 925 'observed' reflections. Crystals are monoclinic, space group P21/c, a 9.036(3), b 9.712(5), c 15.643(6) �, β 97.19(3)�, Z = 4. Although the molecule has no chiral centre, the presence of the three trans double bonds confers considerable distortion and rigidity on the eleven-membered ring and renders the whole molecule chiral and potentially resolvable.

Preparation of Rhenium Diamino Dithiolate Complexes. The X-Ray Crystal Structure of Oxo(1,1,8,8-tetraethyl-3,6-diazaoctane-1,8-dithiolato)rhenium

1993 ◽  
Vol 46 (7) ◽  
pp. 1093 ◽  
Author(s):  
TW Jackson ◽  
M Kojima ◽  
RM Lambrecht
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Intermolecular Hydrogen Bonding ◽  
X Ray ◽  
X Ray Crystallography ◽  
Dithiolate Complexes ◽  
Hydrogen Bonded

The complexes oxo (1,1,8,8-tetraethyl-3,6-diazaoctane-1,8-dithiolato)rhenium[ ReO ( tedadt )], oxo (1,1,8,8-tetraethyl-4,4-dimethyl-3,6-diazaoctane-1,8-dithiolato)rhenium [ ReO ( tedmdadt )] and (1,1,4,4,8,8-hexamethyl-3,6-diazaoctane-1,8-dithiolato) oxorhenium [ ReO ( hmdadt )] were prepared. The crystal structure of the complex ReO ( tedadt ) was determined by X-ray crystallography to be a hydrogen-bonded dimer . This is the first example of intermolecular hydrogen bonding in rhenium diamino dithiolate ( dadt ) complexes.

Beiträge zur Strukturchemie phosphorhaltiger Ketten und Ringe, IX [1]. Die Molekül- und Kristallstruktur von Tri-tert-butylcyclotriphosphanpentacarbonyl- chrom(O), [(t-BuP)3Cr(CO)5] / Structural Chemistry of Phosphorus-Containing Chains and Rings, IX [1]. The Molecular and Crystal Structure of Tri-tert-butylcydotriphosphane-pentacarbonyl-chromium (0), [(t-BuP)3Cr(CO)5]

1984 ◽  
Vol 39 (1) ◽  
pp. 37-42 ◽  
Author(s):  
Karl-Friedrich Tebbe ◽  
Magda Fehér
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Direct Methods ◽  
Membered Ring ◽  
Free Molecule ◽  
Donor Ligand ◽  
Space Group ◽  
X Ray ◽  
Phosphorus Containing

The structure of [(t-BuP)3Cr(CO)5], C17CrH27O5P3, has been determined by single crystal X-ray techniques, solved by ‘direct methods', and refined to R = 0.048, wR = 0.050 for 3657 reflections by blocked least squares. The compound crystallizes in the space group P 21/c with a = 1664.9 pm, b = 916.5 pm , c = 3089.8 pm, β= 91.45° and Z = 8 formula units. The structure consists of two crystallographically independent but structurally nearly identical mononuclear [(t-BuP)3Cr(CO)5] complexes with the three-membered ring (t-BuP)3 as an unidentate σ-donor ligand. Compared to the free molecule (t-BuP)3 the cyclophosphane ligand is slightly distorted on account of its coordination to the Cr(CO)5-group.

Crystal Structure and Chirality of the Ansamycin Antibiotic Actamycin

1991 ◽  
Vol 44 (5) ◽  
pp. 655 ◽  
Author(s):  
TW Hambley ◽  
V Parthasarathi ◽  
RW Rickards ◽  
GB Robertson
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Double Bond ◽  
Least Squares ◽  
Absolute Configuration ◽  
Torsion Angle ◽  
Title Compound ◽  
Intermolecular Hydrogen Bonding ◽  
Triclinic Space Group ◽  
Relative Stereochemistry

The structure of the title compound has been determined from diffractometer data recorded, initially, at 294 K and, subsequently, at 168 K. Crystals are triclinic, space group P1 with (168 K values in square brackets) a 16.080(2) [15.934(2)], b 15.958(2) [15.880(2)], c 8.443(2)Ǻ [8.233(1)Ǻ], α 85.55(1) [86.04(1)],β 82.65(1) [82.56(1)],γ 85.00(1)° [84.73(1)°], and contain two actamycin and two solvent ( tetrahydrofuran ) molecules in the asymmetric scattering unit. The structure was solved with DIRDIF and refined by block-diagonal least-squares analysis (of 168 K data) to R 0.049 ( wR 0.069) for 5640 reflections and 940 refined parameters. Molecules of actamycin (30-dechloro-2-demethyl-30-hydroxynaphthomycin A) exhibit the same relative stereochemistry (8S*,9S*,15S*,18S*,19S*,20S*) and double-bond configuration (2Z,4Z,6E,12E,16E,21E) as reported for crystalline 25-O-methylnaphthomycin A iminomethyl ether but are quite differently conformed. The two crystallographically inequivalent actamycin molecules in the present structure also exhibit substantial conformational (torsion angle) differences due, apparently, to the effects of intermolecular hydrogen bonding. Consideration of chiroptical data defines the absolute configuration of actamycin as 8S,9S,15S,18S,19S,20S and the helicity as P, as in naphthomycin A.

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