Chemistry and Crystal Structures of Some Constituents of Zingiber cassumunar

1979 ◽  
Vol 32 (1) ◽  
pp. 71 ◽  
Author(s):  
T Amatayakul ◽  
J Cannon ◽  
P Dampawan ◽  
T Dechatiwongse ◽  
RF Giles ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Crystal Structures ◽  
Structure Determination ◽  
Aromatic Compounds ◽  
Crystal Structure Determination ◽  
The Novel ◽  
X Ray ◽  
Zingiber Cassumunar ◽  
Block Diagonal

The novel aromatic compounds cis-3-(2',4',5'-trimethoxyphenyl)-4-[(E)-2''',4''',5'''-trimethoxy-styryl]cyclohex-1-ene(1), cis-3-(3',4'-dimethoxyphenyl)-4-[(E)-3''',4'''-dimethoxystyryl]cyclohex-1-ene (2), a substance assigned the tentative structure cis-3-(3',4'-dimethoxyphenyl)-4-[(E)-2''',4''',5'''- trimethoxystyryl]cyclohex-1-ene (3),(E)-4-(3',4'-dimethoxypheny1)but-3-en-1-ol (5), (E)-4-(3',4'-dimethoxypheny1)but-3-en-1-yl acetate (6), and 8-(3',4'-dimethoxyphenyl)-2-methoxynaphtho-1,4- quinone (7) have been isolated from the rhizomes of Zingiber cassurnunav Roxb. (Zingiberaceae). The crystal structures of the cyclohexene derivative (1) and the quinone (7) have been determined from X-ray diffractometer data at 295 K and refined by block diagonal least squares to residuals of 0.046 (2099 'observed' reflections) and 0.093 (1246), respectively. Crystals of compound (1) are triclinic, P1, a 18.027(12), b 10.037(9), c 6.530(5) α, 84.22 (7), β 81.87 (6), γ 85.72 (6)�, Z 2. Crystals of the quinone (7) are monoclinic, P21/a, a 22.89 (1), b 8.022 (5), c 8.458 (5) �, β 91.98 (5)�, Z 4. Although the latter crystal structure determination is imprecise, due largely to the very small size of the crystal available, the solution is unambiguous. A simple two-step synthesis of the quinone (7) has been achieved.

The Anion [Co(C8H12)2]–. A Comparative Study of the Crystal Structures of [{K(18-crown-6)}2(C5H5)][Co(C8H12)2] and Co(C8H12)(C8H13)

2009 ◽  
Vol 64 (8) ◽  
pp. 985-988 ◽  
Author(s):  
Jian-Qiang Wang ◽  
Thomas F. Fässler
Keyword(s):  
Crystal Structure ◽  
Crown Ether ◽  
Comparative Study ◽  
Single Crystal ◽  
Crystal Structures ◽  
Structure Determination ◽  
Cobalt Complex ◽  
Crystal Structure Determination ◽  
X Ray ◽  
Cyclopentadienyl Anion

The cobalt complex [{K(18-crown-6)}2(C5H5)]- [Co(C8H12)2]・(THF)2 (3) has been synthesized and characterized by X-ray single-crystal structure determination. The crystal structure of Co(C8H12)(C8H13) (2) has been reinvestigated and compared with the structure of 3. The 1,5-cyclooctadiene (C8H12) and C8H13 ligands are coordinated in an η4 and η3 fashion, respectively. The cyclopentadienyl anion in [{K(18-crown-6)}2(C5H5)]+ in 3 is η5-coordinated to the two crown ether-encapsulated potassium cations

Synthesis, crystal structure determination, and spectroscopic analyses of 1-chloro-2-(2,6-diisopropylphenyl)-4,4-dimethyl-2-azaspiro[5.5]undecane-3,5-dione: an unyielding precursor to a cyclic (alkyl)(amido)carbene

2021 ◽  
Vol 77 (7) ◽  
Author(s):  
Todd W. Hudnall ◽  
Eric W. Reinheimer ◽  
Christopher L. Dorsey
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Crystal Structures ◽  
Structure Determination ◽  
Crystal Structure Determination ◽  
Close Inspection ◽  
Precursor Molecule ◽  
X Ray ◽  
Spectroscopic Analyses ◽  
C Nmr

The synthesis, single-crystal X-ray structure, and 1H and 13C NMR spectrocopic analyses of an unyielding precursor molecule to a cyclic (alkyl)(amido)carbene, 1-chloro-2-(2,6-diisopropylphenyl)-4,4-dimethyl-2-azaspiro[5.5]undecane-3,5-dione, C24H34ClNO2 (1), is reported. Despite the use of several bases, 1 could not be deprotonated to afford the corresponding carbene. The crystal structure of 1 was compared to the crystal structures of two structurally similar HCl adducts of stable carbenes (compounds 4 and 5), which revealed no significant differences in the geometries about the `carbene' C atoms. To better understand the reactivity differences observed for 1 when compared to 4 and 5, modified percent buried volume (%V bur) calculations were performed. These calculations revealed that the H atom bound to the carbene C atom is the most sterically hindered in compound 1 when compared to 4 and 5 (%V bur = 84.9, 81.3, and 79.3% for 1, 4, and 5, respectively). Finally, close inspection of the quadrant-specific %V bur values indicated that the approach of a deprotonating base to the H atom bound to the carbene C atom is significantly blocked in 1 (69.9%) when compared to 4 and 5 (50.4 and 56.5%, respectively).

Dysidamide, a Novel Metabolite From a Red Sea Sponge Dysidea herbacea

1990 ◽  
Vol 43 (11) ◽  
pp. 1881 ◽  
Author(s):  
S Carmely ◽  
T Gebreyesus ◽  
Y Kashman ◽  
BW Skelton ◽  
AH White ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Red Sea ◽  
Structure Determination ◽  
Crystal Structure Determination ◽  
X Ray ◽  
Dysidea Herbacea ◽  
Chemical Evidence

A hexachloro metabolite, dysidamide (2) has been isolated from a Red Sea sponge Dysidea herbacea. The structure of (2) has been established from spectroscopic and chemical evidence, and confirmed by an X-ray crystal structure determination. Crystals of (2) are orthorhombic P212121, a 20.509(13), b 18.411(11), c 11.356(9)Ǻ, Z 8. The structure was refined by least-squares methods to a residual of 0.049 for 2277 'observed' reflections. Two different conformations of the molecule are present in the crystal.

Notizen: Notiz zur Kristallstruktur von APb2Cl5-Verbindungen / Notice about Crystal Structures of APb2Cl5-Compounds

1976 ◽  
Vol 31 (6) ◽  
pp. 885 ◽  
Author(s):  
H.-L. Keller.
Keyword(s):  
Crystal Structure ◽  
Single Crystals ◽  
Crystal Structures ◽  
Diffraction Data ◽  
Structure Determination ◽  
Crystal Structure Determination ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray

Single crystals of TlPb2Cl5 and NH4Pb2Cl5 were prepared. X-ray diffraction data confirm the space group C2h5—P21/c (No. 14). Crystal structure determination shows a new typ, belonging to the PbCl2-structure.

SIR97: a new tool for crystal structure determination and refinement

1999 ◽  
Vol 32 (1) ◽  
pp. 115-119 ◽  
Author(s):  
Angela Altomare ◽  
Maria Cristina Burla ◽  
Mercedes Camalli ◽  
Giovanni Luca Cascarano ◽  
Carmelo Giacovazzo ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Crystal Structures ◽  
Structure Determination ◽  
Direct Methods ◽  
Crystal Structure Determination ◽  
Previous Version

SIR97 is the integration of two programs,SIR92 andCAOS, the first devoted to the solution of crystal structures by direct methods, the second to refinementvialeast-squares–Fourier procedures. Several new features have been introduced inSIR97 with respect to the previous version,SIR92: greater automatization, increased efficiency of the direct methods section, and a powerful graphics interface. The program also provides publication tables and CIF files.

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