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.

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.

Crystal structure of 2,3-Dichloro-5,8-dihydroxynaphtho-1,4-quinone

1978 ◽  
Vol 31 (3) ◽  
pp. 555 ◽  
Author(s):  
GI Feutrill ◽  
CL Raston ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Least Squares ◽  
Benzene Ring ◽  
Title Compound ◽  
X Ray Diffraction ◽  
Hydrogen Atoms ◽  
X Ray ◽  
The One ◽  
Least Squares Techniques

The crystal structure of the title compound has been determined at 295 K by single-crystal X-ray diffraction methods and refined by least- squares techniques to a residual of 0.049 for 1046 'observed' reflections. Crystals are monoclinic, P21/c, a 11.584(6), b 5.449(7), c 15.273(8) Ǻ, β 92.44(4)°, Z4. The pair of quinol hydrogen atoms are both located on the one benzene ring as the title indicates.

The Quinones of Nepenthes rafflesiana. The Crystal Structure of 2,5-Dihydroxy-3,8-dimethoxy-7-methylnaphtho-1,4-quinone (Nepenthone-E) and a Synthesis of 2,5-Dihydroxy-3-Methoxy-7-methylnaphtho-1,4-quinone (Nepenthone-C)

1980 ◽  
Vol 33 (5) ◽  
pp. 1073 ◽  
Author(s):  
J Cannon ◽  
V Lojanapiwatna ◽  
C Raston ◽  
W Sinchai ◽  
A White
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Dimethyl Ether ◽  
Methyl Ether ◽  
Spectroscopic Properties ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray

Plumbagin (1), droserone (2), hydroxydroserone (4) and four new quinones, nepenthone-A, nepenth-one-B, nepenthone-C (17) and nepenthone-E (9), have been isolated from the roots of Nepenthes rafflesiana Jack. A fifth quinone-nepenthone-D-has been detected in the extract and has been assigned the tentative structure (29) from its spectroscopic properties. ��� The crystal structure of nepenthone-E (9) was determined by X-ray diffraction; diffractometer data at 295 K were refined by full-matrix least squares to a residual of 0.061 (1040 'observed' reflections). Crystals of nepenthone-E (9) are triclinic, Pī a 7.579 (4), b 7.764 (5), c 10.806 (7) Ǻ, α 70.86 (4), β 101.40 (5), γ 91.70 (5)°, Z 2. ��� The structure of nepenthone-C (17) has been confirmed by an unambiguous synthesis. A synthesis of 2,7,8-trimethoxy-3-methyl-5,6-methylenedioxynaphtho-1,4-quinone (49) has revealed that this substance (49) is not identical with the O,O-dimethyl ether of nepenthone-A, and it is suggested that nepenthone-A is either the 5- or 8-O-methyl ether of 2,5,8-trihydroxy-3-methyl-6,7-methylenedioxy-naphtho-1,4-quinone [(36) or (37), respectively].

The Structure of Thiobinupharidine

1973 ◽  
Vol 51 (17) ◽  
pp. 2810-2820 ◽  
Author(s):  
J. T. Wróbel ◽  
B. Bobeszko ◽  
T. I. Martin ◽  
D. B. MacLean ◽  
N. Krishnamachari ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Least Squares ◽  
Absolute Configuration ◽  
Spectroscopic Properties ◽  
Relative Configuration ◽  
Full Matrix ◽  
Space Group ◽  
R Value ◽  
Least Squares Techniques

The spectroscopic properties of thiobinupharidine and its isomer, neothiobinupharidine, of established structure, have been examined and compared. From this study it was possible to deduce the structure and relative configuration of the alkaloid. The structure has been firmly established and the absolute configuration determined by the study of the crystal structure of thiobinupharidine dihydrobromide dihydrate, C30H42O2N2S•2HBr•2H2O. The crystals are orthorhombic with space group C2221, a = 25.128(6), b = 9.869(2), c = 26.380(6) Å, and Z = 8. The structure was refined, using full-matrix least-squares techniques with 1934 reflections, to a final R value of 0.097. The thiobinupharidine moiety hydrogen bonds to one of two types of H2O–Br–H2O spiral chains in the structure. The tetrahydrothiophene ring is distorted from planarity, and this together with the nonequivalence of the S and C atoms in the ring causes the molecule to deviate from C2 symmetry

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.

Selective O-Demethylation of 5,8-Dihydroxy-2,3-Dimethoxy-6-Methylnaphtho-1,4-Quinone: The Crystal Structures of 5,8-Dihydroxy-2,3-Dimethoxy-6-Methylnaphtho-1,4-Quinone and 2,5,8-Triacetoxy-3-Methoxy-6-Methylnaphtho-1,4-Quinone

1987 ◽  
Vol 40 (7) ◽  
pp. 1191 ◽  
Author(s):  
JR Cannon ◽  
Y Matsuki ◽  
VA Patrick ◽  
AH White
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Sodium Hydroxide ◽  
Crystal Structures ◽  
Hydrolysis Product ◽  
Aqueous Sodium Hydroxide ◽  
X Ray Diffraction ◽  
Aqueous Sodium ◽  
X Ray ◽  
Least Squares Techniques

It has been confirmed that treatment of 5,8-dihydroxy-2,3-dimethoxy-6-methylnaphtho-1,4- quinone (1) with dilute aqueous sodium hydroxide leads to selective O- demethylation. The hydrolysis product has been identified as 2,5,8-trihydroxy-3-methoxy-6-methylnaphtho1,4- quinone (3) from the crystal structure of the corresponding triacetate (4). The crystal structures of 5,8-dihydroxy-2,3-dimethoxy-6-methylnaphtho-1,4-quinone (1) and 2,5,8-triacetoxy-3-methoxy-6-methylnaphtho-1,4-quinone (4) were determined by X-ray diffraction; diffractometer data at 295 K were refined by least squares techniques to residuals of 0.074 (583 'observed' reflections) for (1) and 0.049 (2005) for (4). Crystals of (1) are monoclinic, P2l/c, a 3.873(4), b 20.21(1), c 15.OO(2) �, β 96.05(6)�, Z 4. Crystals of (4) are also monoclinic, P2l/c, a 10.532(5), b 14.596(6), c 12.097(6) �, β 109.74(4)�, Z 4.

The X-Ray Crystal-Structure of (+/-)-Pandamarine, the Major Alkaloid of Pandanus-Amaryllifolius

1992 ◽  
Vol 45 (11) ◽  
pp. 1903 ◽  
Author(s):  
LT Byrne ◽  
BQ Guevara ◽  
WC Patalinghug ◽  
BV Recio ◽  
CR Ualat ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Least Squares ◽  
Diffraction Study ◽  
X Ray Diffraction ◽  
X Ray ◽  
Least Squares Techniques ◽  
Pandanus Amaryllifolius

The structure (2) of ( �)-pandamarine , the major alkaloid isolated from the leaves of Pandanus amaryllifolius Roxb., has been determined by an X-ray diffraction study. Diffractometer data at 295 K were refined by least-squares techniques to a residual of 0.049 2244 'observed' reflections). Crystals of (2) are triclinic, P1, a 13.077(2), b 9.857(5), c 7.214(2) �, α 106.91(3), β 96.22(2), γ 100.01(2)0, Z 2.

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.

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