Crystal structure and absolute configuration of (+)-scandine hydrobromide

1982 ◽  
Vol 35 (8) ◽  
pp. 1655 ◽  
Author(s):  
JR Cannon ◽  
KD Croft ◽  
Y Matsuki ◽  
VA Patrick ◽  
RF Toia ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Absolute Configuration ◽  
Steric Effect ◽  
X Ray Diffraction ◽  
Methyl Group ◽  
X Ray ◽  
Block Diagonal

The major alkaloid of a Fijian Melodinus sp. (family Apocynaceae) has been identified as (+)-scandine (1). The crystal structure and absolute configuration of the acetone solvate of (+)-scandine hydrobromide have been determined by X-ray diffraction; diffractometer data at 295 K were refined by block diagonal least squares to a residual of 0.037 (2657 'observed' reflections). Crystals of the hydrobromide are monoclinic, P21, a 9.496(3), b 14.561(5), c 9.339(3) �, β 115.39(2)�, Z 2. Although the cations of (+)-scandine hydrobromide and (+)-N-methylmeloscine bromide have the same skeleton and the same absolute configuration, they have different conformations; this appears to be due to the steric effect of the N-methyl group in the latter cation.

The Alkaloids of Margaritaria indica (Euphorbiaceae). The Crystal Structure and Absolute Configuration of the Hydrobromide of (+)-15α-Methoxy-14,15-dihydrophyllochrysine

1990 ◽  
Vol 43 (2) ◽  
pp. 439 ◽  
Author(s):  
D Arbain ◽  
LT Byrne ◽  
JR Cannon ◽  
LM Engelhardt ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Absolute Configuration ◽  
Spectroscopic Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Least Squares Techniques

(-)-Phyllochrysine (1), (-)-securinine (2) and a new alkaloid (+)-15α-methoxy-14,15-dihydrophyllochrysine (3) have been isolated from both the bark and roots of Margaritaria indica ( Dalz .) G. L. Webster. The structure and absolute configuration of (3) follow from its spectroscopic properties and its synthesis from (-)- phyllochrysine (1) as well as from the crystal structure of its hydrobromide, obtained by X-ray diffraction. Diffractometer data at 295 K were refined by least-squares techniques to a residual of 0.053 (991 'observed' reflections). Crystals of 15α-methoxy-14,15-dihydrophyllochrysine hydrobromide are orthorhombic, P212121, a 14.324(3), b 14.194(3), c 7.240(2)Ǻ, Z 4.

The crystal structure of (S)-( - )-6-Bromo-5,7-dihydroxy-8-methyl-2-phenyl-2,3-dihydro-4H-1-benzopyran-4-one [( - )-6-bromocryptostrobin] and a 13C N.M.R. study of (±)-cryptostrobin and related substances. Revision of the structures of the natural products (±)-lawinal, unonal, 7-O-methylunonal and isounonal

1982 ◽  
Vol 35 (9) ◽  
pp. 1851 ◽  
Author(s):  
LT Byrne ◽  
JR Cannon ◽  
DH Gawad ◽  
BS Joshi ◽  
BW Skelton ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Natural Products ◽  
Least Squares ◽  
Crystallographic Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Related Substances ◽  
Block Diagonal

The crystal structure of (S)-(-)-6-bromo-5,7-dihydroxy-8-methyl-2-phenyl-2,3-dihydro-4H-1-benzopyran-4-one [(–)-6-bromocryptostrobin] (11) has been determined by X-ray diffraction from diffractometer data at 295 K and refined by block diagonal least squares to a residual of 0.050 (810 'observed' reflections). Crystals of (11) are tetragonal, P43212, a 7.849(4), c 46.83(2) �, Z 8. The crystallographic data are consistent with the S configuration previously proposed for (–)-cryptostrobin (10). The 13C n.m.r, spectra of (�)-cryptostrobin and(�)-strobopinin also lead to the structures (1) and (6), respectively. This work has enabled the structures proposed for the natural products (�)-lawinal, unonal, 7-O-methylunonal and isounonal to be revised to (8), (14), (15) and (12), respectively.

Alkaloids of Templetonia retusa. Chemistry, Structure and Absolute Configuration of (-)-Templetine

1991 ◽  
Vol 44 (4) ◽  
pp. 509 ◽  
Author(s):  
JR Cannon ◽  
JR Williams ◽  
D Arbain ◽  
A Brossi ◽  
JF Blount ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Carbon Disulfide ◽  
Absolute Configuration ◽  
Perchloric Acid ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Absolute ◽  
Absolute Structure ◽  
Least Squares Techniques

(-)-Cytisine, (+)-lupanine, (-)-anagyrine, (�)-piptanthine and (-)-templetine have been isolated from Templetonia retusa (Vent.) R.Br. The absolute crystal structures of the trihydrochloride dihydrate and the isomorphous trihydrobromide dihydrate of (-)- templetine have both been determined by single-crystal X-ray diffraction; diffractometer data at 295 K were refined by least-squares techniques to residuals of 0.045 and 0.031, respectively, for 2351 and 1948 'observed' reflections. Crystals of the trihydrochloride are orthorhombic P212121, a 8.830(4), b 14.201(6), c 19.122(12)Ǻ, Z 4. Crystals of the trihydrobromide are isomorphous, a 9.081(3), b 14.578(2), c 19.197(11)Ǻ, Z 4. The absolute structure (1) of (-)- templetine has led to the absolute structure of its dehydrogenation product (-)- dehydropiptanthine perchlorate (7) which, in turn, has allowed the absolute structures of (-)- ormosanine (6), (+)- piptanthine (4) and (-)- panamine (9) to be defined. (-)- Templetine (1) reacts with formaldehyde to form homotempletine (12) and with carbon disulfide to yield the thiourea (13). Treatment of either (12) or (13) with W-1 Raney nickel followed by perchloric acid has yielded the diperchlorate (15). The X-ray crystal structure of the diperchlorate (15) has also been determined: diffractometer data at 295 K were refined by least-squares techniques to a residual of 0.056 (1312 'observed' reflections). Crystals of the diperchlorate (15) are orthorhombic, P212121, a 18.636(5), b 12.569(6), c 10.403(4)Ǻ, Z 4.

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.

Crystal structure of ab-Bis(3-methylpyridine)-dc,fe-bis(pentane-2,3,4-trione 3-oximato)iron(II)

1978 ◽  
Vol 31 (11) ◽  
pp. 2431 ◽  
Author(s):  
BN Figgis ◽  
CL Raston ◽  
RP Sharma ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Title Compound ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chelate Ligands

The crystal structure of the title compound has been determined at 295 K by single-crystal X-ray diffraction and refined by least squares to a residual of 0.062. Crystals are monoclinic, P2/c, a 19.102(8), b 8.117(4), c 16.610(8) Ǻ, β 111.90(3)°, Z. Unlike the tris(α-oxyimino ketonato)iron(II) complexes which are fac, the present derivative is based upon substitution of the two picoline moieties into a mer derivative, trans to the nitrogen atoms of the chelate ligands. <Fe- N(picoline)> is 2.020; <Fe-N, O(chelate)> 1.880, 1.952 Ǻ.

Crystal structure of (E)-7-t-Butyl-5-methoxy-3-[(E)-2'-methoxy-5',5'-dimethyl-4'-oxohex-2'-enylidene]benzofuran-2(3H)-one

1977 ◽  
Vol 30 (9) ◽  
pp. 1979 ◽  
Author(s):  
SR Hall ◽  
CL Raston ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Preceding Paper ◽  
X Ray Diffraction ◽  
X Ray

The crystal structure of (E)-7-t-butyl-5-methoxy-3-[(E)-2?-methoxy- 5?,5?-dimethyl-4?-oxohex-2?enylidene]benzofuran-2(3H)-one, C22H28O5 (see preceding paper), has been determined by single-crystal X-ray diffraction at 295(1) K and refined by least squares to a residual of 0.067 (3735 ?observed? reflections). Crystals are triclinic, Pī, a 14.955(7), b 13.142(5), c 10.910(3) Ǻ, α 85.76(3), β 85.67(3), γ 80.12(3)�, Z 4.

Crystal-to-Crystal Diastereoselective Transformation of 2,4,6-Triisopropyl-4'-(S)-phenylalaninocarbonylbenzophenone Methyl Ester

1998 ◽  
Vol 54 (6) ◽  
pp. 907-911 ◽  
Author(s):  
H. Hosomi ◽  
Y. Ito ◽  
S. Ohba
Keyword(s):  
Crystal Structure ◽  
High Pressure ◽  
Methyl Ester ◽  
Absolute Configuration ◽  
Crystal Structure Analysis ◽  
X Ray Diffraction ◽  
Pass Filter ◽  
X Ray ◽  
Ultra High Pressure ◽  
Phenylalanine Methyl Ester

Dissymmetry of the photoproduct was induced by using a chiral substituent, (S)-methylphenylalanine, in the title compound {N-4-(2,4,6-triisopropylbenzoyl)benzoyl]-(S)-phenylalanine methyl ester (I)}. On irradiation with light from a 250 W ultra-high-pressure Hg lamp for 7 h through a long-pass filter, the photoreaction in a crystal was 100% complete without the loss of crystallinity. The crystal structures (I), before, and (II) {N-[4-(7-hydroxy-3,5-diisopropyl-8,8-dimethylbicyclo[4.2.0]octa-1,3,5-trien-7-yl)benzoyl]-(S)-phenylalanine methyl ester}, after photocyclization, have been determined by X-ray diffraction. For comparison, a crystal structure analysis has also been carried out for the photoproduct (III) of the 3′-COOMe derivative after recrystallization {methyl 3-(7-hydroxy-3,5-diisopropyl-8,8-dimethylbicyclo[4.2.0]octa-1,3,5-trien-7-yl)benzoate}. The dihedral angle between the central carbonyl plane and the triisopropylphenyl ring deviates from 90° by 10 (1)° in (I), which makes an imbalance in the intramolecular O(carbonyl)...H(methine) distances of the isopropyl groups at positions 2 and 6. The crystal structure of (II) indicates that the nearer methine H was predominantly abstracted by the carbonyl O atom in the reaction. The absolute configuration around the asymmetric C atom in the cyclobutenol ring of the product is S.

The crystal structure of dibutyl-bis(pentamethylenedithiocarbamato)tin(IV)

1986 ◽  
Vol 51 (11) ◽  
pp. 2521-2527 ◽  
Author(s):  
Jan Lokaj ◽  
Eleonóra Kellö ◽  
Viktor Kettmann ◽  
Viktor Vrábel ◽  
Vladimír Rattay
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Least Squares ◽  
Coordination Polyhedron ◽  
Crystal And Molecular Structure ◽  
Distorted Octahedron ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Space Group ◽  
X Ray

The crystal and molecular structure of SnBu2(pmdtc)2 has been solved by X-ray diffraction methods and refined by a block-diagonal least-squares procedure to R = 0.083 for 895 observed reflections. Monoclinic, space group C2, a = 19.893(6), b = 7.773(8), c = 12.947(8) . 10-10 m, β = 129.07(5)°, Z = 2, C20H38N2S4Sn. Measured and calculated densities are Dm = 1.38(2), Dc = 1.36 Mg m-3. Sn atom, placed on the twofold axes, is coordinated with four S atoms in the distances Sn-S 2.966(6) and 2.476(3) . 10-10 m. Coordination polyhedron is a strongly distorted octahedron. Ligand S2CN is planar.

Crystal structure of Tetracyclo[5,3,1,12,6,04,9]dodecane (iceane)

1977 ◽  
Vol 30 (8) ◽  
pp. 1837 ◽  
Author(s):  
DPG Hamon ◽  
CL Raston ◽  
GF Taylor ◽  
JN Varghese ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Rigid Body ◽  
Least Squares ◽  
Title Compound ◽  
Molecular Geometry ◽  
Thermal Motion ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray ◽  
Hexagonal Close Packed

The crystal structure of the title compound, C12H18, has been determined at 295 K by X-ray diffraction and refined by full-matrix least squares to a residual of 0.049 for 216 ?observed? reflections; molecular geometry has been corrected for the effects of thermal motion using a rigid body approximation. Crystals are hexagonal, P63/m, a = 6.582(1), c = 11.843(3) Ǻ, Z = 2, the molecules occupying a hexagonal close- packed array.

Crystal structure of (Z)-Cembr-4-ene-15,19,20-triol

1977 ◽  
Vol 30 (12) ◽  
pp. 2723 ◽  
Author(s):  
EN Maslen ◽  
CL Raston ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Double Bond ◽  
Single Crystal ◽  
Least Squares ◽  
Structure Determination ◽  
Title Compound ◽  
X Ray Diffraction ◽  
Relative Configuration ◽  
Macrocyclic Ring ◽  
X Ray

The crystal structure of the title compound, CZOH3803 [compound (1) in ref.'], has been determined by single-crystal X-ray diffraction at 295(1) K and refined by least squares to a residual of 0.045 for 954 'observed' reflections. Crystals are monoclinic, P2', a 9.281(2), b 17.798(6), c 6.417(1) A, B 93.81(3)", Z 2. The structure determination establishes the relative configuration of the chiral centres within the 14-membered macrocyclic ring and shows the double bond to have the unusual (Z) configuration.

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