5-Isopropyltropolone, γ-thujaplicin

Berg, Jan-Eric; Karlsson, Bengt; Pilotti, A.-M.; Wiehager, Anne‐Charlotte

doi:10.1107/s0567740876009722

Cited by 8 publications

(7 citation statements)

References 4 publications

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“…The puckering in the rings may alternatively be described by the torsion angles in Fig. 3 found here agrees closely with that reported for other structures containing troponoid rings (Margulis, 1974(Margulis, , 1975Koerntgen & Margulis, 1977;Shimanouchi & Sasada, 1973;Derry & Hamor, 1972;Hamor & Derry, 1973;Karlsson, Pilotti & Wiehager, 1973, 1976Berg, Karlsson, Pilotti & Wiehager, 1976). However, the pattern of ring puckering and the extent of non-planarity seem to vary among these compounds.…”

Section: Resultssupporting

confidence: 89%

The crystal structure of colchicine. A new application of magic integers to multiple-solution direct methods

Lessinger¹,

Margulis²

1978

Acta Crystallogr Sect B

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The mitotic spindle inhibitor colchicine, C22H25NO6, crystallizes as a dihydrate in space group P21, a = 17.08, b = 10.70, c = 13.88 A, fl = 117.9 °, Z = 4(C22H25NO6.2H20)/unit cell. The crystal structure was solved by a multiple-solution direct method in which unknown starting phases ~l are represented using 'magic integers': tp I = mix. An appropriate choice of integers m I and sampling of the variable x allows a drastic reduction in computing time and a great increase in structure-solving capability compared to the widely used method in which all unknown phases are permuted among the four values 45, 135, 225, 315 °. The crystal structure of colchicine dihydrate was refined by least squares to R = 0.052 for 2322 observed X-ray reflections. The two independent colchicine molecules have very similar conformations in the crystal. The troponoid rings have alternating bond lengths, and are not precisely planar. These rings make dihedral angles with the planar benzene rings of 53 ° in one molecule of eolchicine, 51 o in the other. The four independent water molecules are all found in a distinct region in the crystal, which is held together by a complex hydrogenbond network. Two methoxy-group O atoms of colchicine act as hydrogen-bond acceptors, the one on the troponoid ring participating in a bifurcated hydrogen bond.Colchicine (I), the principal active substance of the autumn crocus, has a remarkable range of biological effects. The most studied of these is its arrest of mitosis, believed to result from the specific strong binding of eolehicine to the protein tubulin, preventing the assembly of tubulin into mierotubules which form the mitotic spindle (Soifer, 1975). Colchicine is also capable of relieving the pain of gout (for which it has been used since ancient times), of inducing polyploidy * Present address:

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Section: Resultssupporting

confidence: 89%

The crystal structure of colchicine. A new application of magic integers to multiple-solution direct methods

Lessinger¹,

Margulis²

1978

Acta Crystallogr Sect B

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“…The tropolone rings exhibit bond-length alternation in accordance with those in the crystal structures of fl-thujaplicin (Derry & Hamor, 1972), ~,-thujaplicin (Berg, Karlsson, Pilotti & Wiehager, 1976), tropolone (Shimanouchi & Sasada, 1973) and chanootin (Karlsson, Pilotti & Wiehager, 1973). Bond lengths from these studies together with the results of a molecular orbital treatment of tropolone (Dewar & Trinajstic, 1970) are listed in Table 3.…”

Section: Torsion Anglessupporting

confidence: 72%

Utahin, a ditropolonofuran

Karlsson¹,

Pilotti²,

Wiehager³

1976

Acta Crystallogr Sect B

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“…The crystal structures of tropolone (Shimanouchi & Sasada, 1973) and other mono-substituted tropolones, such as 5nitro-, 5-cyano- (Kubo et al, 2001), 5-methyl- (Kubo et al, 2007b), 5-methoxy- (Kubo et al, 2006b), 5-acetoxy- (Kubo et al, 2006a), 5-iodo- (Kubo et al, 2007d), 7-iodo- (Kubo et al, 2007c), 4-isopropyl- (Derry & Hamor, 1972), 5-isopropyl- (Berg et al, 1976), 7-hydroxy- (Kubo et al, 2007a), 7-chlorotropolone (Tsuji et al, 1991), have been reported previously.…”

Section: Methodsmentioning

confidence: 89%

“…For the structure of tropolone and 5-nitrotropolone, see: Shimanouchi & Sasada (1973); Kubo et al (2001), respectively. Structural data on other mono-substituted tropolones were reported by Derry & Hamor (1972); Berg et al (1976); Tsuji et al (1991); Kubo et al (2001Kubo et al ( , 2006aKubo et al ( ,b, 2007a. For the synthesis of nitrotropolone, see Cook et al (1954).…”

Section: Related Literaturementioning

confidence: 92%

2-Hydroxy-7-nitrocyclohepta-2,4,6-trien-1-one

Łyczko¹,

Lyczko²

2013

Acta Cryst E

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The title compound, also known as 7-nitrotropolone, C7H5NO4, exists in the crystalline state as the 2-hydroxy-7-nitrocyclohepta-2,4,6-trien-1-one tautomer and not as 2-hydroxy-3-nitrocyclohepta-2,4,6-trien-1-one. The dihedral angle between the ring and the nitro group is 70.3 (2)°. In the crystal, neighbouring molecules are linked into dimers by a pair of O—H⋯O hydrogen bonds. In addition, the crystal is stabilized by O⋯π [3.4039 (14) Å] and O⋯O [3.073 (2) Å] interactions.

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5-Isopropyltropolone, γ-thujaplicin

Cited by 8 publications

References 4 publications

The crystal structure of colchicine. A new application of magic integers to multiple-solution direct methods

The crystal structure of colchicine. A new application of magic integers to multiple-solution direct methods

Utahin, a ditropolonofuran

2-Hydroxy-7-nitrocyclohepta-2,4,6-trien-1-one

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