The Molecular and Crystal Structure of an Oxindole Alkaloid (6-Hydroxy-2′-(2-methylpropyl)-3,3′-spirotetrahydropyrrolidino-oxindole)

1972 ◽  
Vol 50 (15) ◽  
pp. 2407-2412 ◽  
Author(s):  
M. N. G. James ◽  
G. J. B. Williams

A previously unknown alkaloid of molecular formula C15H20O2N2 was isolated from the dried root bark of EleagnusCommutata (Wolf willow or Silverberry). An X-ray analysis was undertaken to complete the structural characterization of the molecule. Columnar crystals obtained from diethyl ether have the unit cell constants, a = 13.1949(10) Å, b = 9.4525(6) Å, c = 12.1186(6) Å, β = 109°47(1)′ and belong to space group P21/c. The structure was solved using an automated symbolic addition procedure and refined by block-diagonal least-squares to weighted and unweighted R factors of 6.25% and 4.30%, respectively. The previous structural studies were shown to be essentially correct except for the incorrect placement of the phenolic hydroxyl on C(5) of the oxindole nucleus. The correct molecular structure is implied by the systematic name given. The —OH group engages in two intermolecular hydrogen bonds with the two nitrogen atoms, but the carbonyl moiety is not involved in any such interactions.

2013 ◽  
Vol 683 ◽  
pp. 357-360
Author(s):  
Hai Xing Liu ◽  
Jing Zhong Xiao ◽  
Ping Yang ◽  
Zhang Xue Yu ◽  
Qing Hua Zhang ◽  
...  

A novel ytterbium chloride phenanthroline [YbCl4]·[C12H8N2]·(H2O) has been synthesized from a single solution reaction and the crystal structure has been determined by means of single-crystal X-ray diffraction. The Yb atom is coordinated by six Cl atoms. The plane quadrilateral is formed by two Cl2 and two Yb atoms. Molecules form O—H…Cl , O—H…O , O—H…N intramolecular and intermolecular hydrogen bonds and stabilized the molecular structure.


2013 ◽  
Vol 634-638 ◽  
pp. 451-455
Author(s):  
Yan Yang ◽  
Liu Ting Yan ◽  
Rong Huan Qin ◽  
Wen Gui Duan

The lead(II) Complex constructed with 5-hydroxyisophthalic acid, [Pb3(5-hipa)2]n•4H2O(1), (5-hipa = 5-hydro- xyisophthalic acid) has been synthesized by hydrothermal methods and structurally characterized by elemental analysis, IR and X-ray single crystal diffraction. In trinuclear symmetrical complex 1, Pb1 is four-coordinated, Pb2 and Pb3 are three-coordinated by 5-nitroisophthalic acid groups, respectively, which is further connected through intermolecular hydrogen bonds resulting in a three-dimensional (3D) network.


2017 ◽  
Vol 5 (1) ◽  
pp. 35
Author(s):  
Gene-Hsiang Lee ◽  
Long-Chih Hwang

The X-ray structural investigations has been carried out for the title compound, 2-[(2-acetoxyethoxy)methyl]-3-amino-1,2,4-triazin-5(2H)-one (1-[(2-acetoxyethoxy)methyl]-6-azaisocytosine), molecular formula C8H12N4O4, crystallizes in a monoclinic space group P-1 with a = 5.3124(3) Å, b = 7.3635(3) Å, c = 14.0170(8) Å, α = 81.5265(19)°, β = 85.852(2)°, γ = 76.760(2)°, V = 527.49(5) Å3 and Z = 2, resulting in a density, Dcalc, of 1.437 g/cm3. The hydrogen-bonding systems assemble with N-H···O [graph set C (6)], N-H···N [graph set R  (8)], and N-H···N combine with N-H···O [graph set R (12)]. The side chain of the molecular structure is further stabilized by short contacts formed by intermolecular C-H···O interactions.


2010 ◽  
Vol 65 (4) ◽  
pp. 475-478
Author(s):  
Guido D. Frey ◽  
Eberhardt Herdtweck

The crystal structure of the stable nitroxide radical 3-(N-methoxy-N-methylcarbamoyl)-2,2,5,5- tetramethyl-1-oxy-pyrroline was determined from single-crystal X-ray data: orthorhombic, space group Pbca (no. 61), a = 9.0213(1), b = 12.8625(1), c = 21.2406(2) Å, V = 2464.68(4) Å3 and Z = 8. The adjacent molecules assemble to a supramolecular layer structure in the solid state, linked by two intermolecular C-H...O hydrogen bonds.


2002 ◽  
Vol 57 (11) ◽  
pp. 1315-1319 ◽  
Author(s):  
Irena Wolska ◽  
Franciszek Herold

The X-ray crystal structure determination of 4-(2-methylphenyl)hexahydro-1H,3H-pyrido[ 1,2-c]pyrimidine-1,3-dione (2) and 4-(3-methylphenyl)hexahydro-1H,3H-pyrido[1,2-c]- pyrimidine-1,3-dione (3) is reported. The crystal structures show the formation of centrosymmetric dimers via intermolecular N-H···O hydrogen bonds. The saturated ring adopts a slightly distorted halfchair conformation in both 2 and 3. In either compound the planar phenyl ring is twisted with respect to the pyrimidine-1,3-dione fragment.


1996 ◽  
Vol 51 (8) ◽  
pp. 1084-1098 ◽  
Author(s):  
Rolf W. Saalfrank ◽  
Bernd Hörner ◽  
Stephan Reck ◽  
Jochen Nachtrab ◽  
Eva-Maria Peters ◽  
...  

Reaction of malondiamides 1 with oxalyl chloride (2) leads to the formation of 2,3-dioxo-2,3- dihydrofuran hydrochlorides 3 and 2,3-dioxo-2,3-dihydro-furanes 4, respectively. The structure of 3a was established by X-ray diffraction. The β-oxo-dibenzylamides 5 react with 2 regiospecifically to give the 2,3-dioxo-2,3-dihydrofuranes 6. Addition of water in 1,4-position to 6a yields hydroxy-enol 7, which forms bimolecular aggregates via intermolecular hydrogen bonds as shown by X-ray analysis. Intramolecular C,N-bisacylation of β-oxoamides 8 and malondiamides 11 with 2 leads to the pyrrol-2,5-diones 9 and 12. Reaction of the enols 9 and 12 with thionyl chloride leads to 3-chloro-pyrrol-2,5-diones 13. 3-Amino-pyrrol-2,5-diones 15 are obtained from 13 and amines 14, while 1, ω-diamines 16 yield the bispyrrol systems 17. X-ray diffraction analysis of 17g reveals a supramolecular ribbon based on intermolecular hydrogen bonds between two different conformeres of 17g and in addition establishes unequivocally the imid-structures of 9 and 12. Intermolecular cyclisation of 13 with amino-tetrazol 18 gives the azido-pyrrolo-pyrimidine-diones 20, which reacts with triphenylphosphane to give phosphinimines 22. The structure of 22a was established by X-ray diffraction.


Author(s):  
A. Whitaker

AbstractThe crystal and molecular structure of C.I. Pigment Red 2, l′-(2,5-dichlorophenyl)azo-2′-hydroxy-3′-phenylamidonaphthalene has been determined by x-ray diffraction techniques. It crystallizes in the monoclinic system with cell parametersThe hydrogen atoms have been found and included but not refined. The final residual is 15.3%. The molecule is probably in the form of the hydrazone tautomer. The intramolecular hydrogen bonds keep most of the molecule approximately planar while it appears that the remainder is held in the same plane due to steric hinderence between the molecules. The molecules are packed in columns with alternate molecules antiparallel and are linked by van der Waals forces.


Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1407
Author(s):  
Toshifumi Yui ◽  
Takuya Uto ◽  
Kozo Ogawa

We determined the molecular and packing structure of a chitosan–ZnCl2 complex by X-ray diffraction and linked-atom least-squares. Eight D-glucosamine residues—composed of four chitosan chains with two-fold helical symmetry, and four ZnCl2 molecules—were packed in a rectangular unit cell with dimensions a = 1.1677 nm, b = 1.7991 nm, and c = 1.0307 nm (where c is the fiber axis). We performed exhaustive structure searches by examining all of the possible chain packing modes. We also comprehensively searched the positions and spatial orientations of the ZnCl2 molecules. Chitosan chains of antiparallel polarity formed zigzag-shaped chain sheets, where N2···O6, N2···N2, and O6···O6 intermolecular hydrogen bonds connected the neighboring chains. We further refined the packing positions of the ZnCl2 molecules by theoretical calculations of the crystal models, which suggested a possible coordination scheme of Zn(II) with an O6 atom.


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