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(1S,2S,5R,8S,11S,14R,17S,20R)-14-Methyl-6-methyl-ene-10,16,18-trioxa-hexa-cyclo-[12.5.1.1.0.0.0]henicosane-7,9-dione: natural diter-penoid macrocalyxoformin B.

ABSTRACT: The title compound, C(20)H(24)O(5), isolated from Rabdosia var. lophanthoides Hara, is built up from six fused rings. Cyclo-hexane ring A adopts a chair conformation, ring B exists in a screw-boat conformation and ring C adopts a boat conformation; the three five-membered rings D, E and F adopt envelope conformations.

SUBMITTER: Shi H

PROVIDER: S-EPMC2915036 | biostudies-literature | 2007 Dec

REPOSITORIES: biostudies-literature

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(1S,2S,5R,8S,11S,14R,17S,20R)-14-Methyl-6-methyl-ene-10,16,18-trioxa-hexa-cyclo-[12.5.1.1.0.0.0]henicosane-7,9-dione: natural diter-penoid macrocalyxoformin B.

Shi Hao H

Acta crystallographica. Section E, Structure reports online 20071206 Pt 1

The title compound, C(20)H(24)O(5), isolated from Rabdosia var. lophanthoides Hara, is built up from six fused rings. Cyclo-hexane ring A adopts a chair conformation, ring B exists in a screw-boat conformation and ring C adopts a boat conformation; the three five-membered rings D, E and F adopt envelope conformations. ...[more]

PMID: 21200956

Similar Datasets

Analogues of amphibian alkaloids: total synthesis of (5R,8S,8aS)-(-)-8-methyl-5-pentyloctahydroindolizine (8-epi-indolizidine 209B) and [(1S,4R,9aS)-(-)-4-pentyloctahydro-2H-quinolizin-1-yl]methanol.

Project description:BackgroundPrior work from these laboratories has centred on the development of enaminones as versatile intermediates for the synthesis of alkaloids and other nitrogen-containing heterocycles. In this paper we describe the enantioselective synthesis of indolizidine and quinolizidine analogues of bicyclic amphibian alkaloids via pyrrolidinylidene- and piperidinylidene-containing enaminones.ResultsOur previously reported synthesis of racemic 8-epi-indolizidine 209B has been extended to the laevorotatory enantiomer, (-)-9. Attempts to adapt the synthetic route in order to obtain quinolizidine analogues revealed that a key piperidinylidene-containing enaminone intermediate (+)-28 was less tractable than its pyrrolidinylidene counterpart, thereby necessitating modifications that included timing changes and additional protection-deprotection steps. A successful synthesis of [(1S,4R,9aS)-4-pentyloctahydro-2H-quinolizin-1-yl]methanol (-)-41 from the chiral amine tert-butyl (3R)-3-{benzyl [(1R)-1-phenylethyl]amino}octanoate (+)-14 was achieved in 14 steps and an overall yield of 20.4%.ConclusionThe methodology reported in this article was successfully applied to the enantioselective synthesis of the title compounds. It paves the way for the total synthesis of a range of cis-5,8-disubstituted indolizidines and cis-1,4-disubstituted quinolizidines, as well as the naturally occurring trans-disubstituted alkaloids.

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(1S,3R,8R,11S)-2,2-Dichloro-3,7,7,10-tetra-methyl-tricyclo-[6.4.0.0]dodec-9-en-11-ol.

Project description:The title compound, C(16)H(24)Cl(2)O, was synthesized from β-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzocyclo-heptene), which was isolated from essential oil of the Atlas cedar (Cedrus atlantica). The two fused rings exhibit different conformations: the six-membered ring has a screw-boat conformation, while the seven-membered ring displays a boat conformation. The dihedral angle between the two rings is 56.56 (18)°. In the crystal, mol-ecules aggregate into supra-molecular chains along the c axis mediated by O-H⋯O hydrogen bonds.

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(1S,3R,8S,9R,10S)-2,2-Dichloro-3,7,7,10-tetra-methyl-9,10-ep-oxy-tricyclo-[6.4.0.0]dodeca-ne.

Project description:The title compound, C(16)H(24)Cl(2)O, was synthesized from ?-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzocyclo-heptene), which was isolated from the essential oil of the Atlas cedar (cedrus atlantica). The mol-ecule forms an extended sheet of two fused rings which exhibit different conformations. The six-membered ring has a half-chair conformation, while the seven-membered ring displays a chair conformation; the dihedral angle between the two rings is 38.2?(1)°.

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(1S,3R,8R,11S)-11-Bromo-10-bromo-methyl-2,2-di-chloro-3,7,7-tri-methyl-tricyclo-[6.4.0.0(1,3)]dodec-9-ene.

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(-)-(1S,5R)-2-Oxabicyclo-[3.3.1]nonan-3-one.

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(1S,5R,7R,30S)-14-De-oxy-isogarcinol.

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1-[(1S,6R,7S,9R)-8,8-Di-bromo-5,5,9-tri-methyl-tri-cyclo-[4.4.0.1(7,9)]decan-1-yl]ethanone.

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Project description:In the title compound, C23H38O5, the oxabicyclo-[2.2.1]heptane-2,3-dicarb-oxy-lic anhydride unit has a normal geometry and the tetra-decoxymethyl side chain is fully extended. In the crystal, mol-ecules are linked head-to-head by C-H⋯O hydrogen bonds, forming two-dimensional networks propagating along the a and c-axis directions.

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(4aS,5R,7R,8S,8aR)-8-(1,3-Dioxolan-2-yl)-7,8-dimethyl-5-(1-methyl-ethen-yl)perhydro-naphthalen-2-one.

Project description:In the chiral title compound, C(18)H(28)O(3), the two six-membered rings of the perhydronaphthalenone adopt a rigid chair-chair conformation and the five-membered dioxolanyl ring adopts an envelope conformation. The crystal structure is stabilized only by weak inter-actions.

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(4R,5R,6S,7R,8S,9R,10S,13S)-7,8β-Epoxy-momilactone-A.

Project description:The title compound, C(20)H(26)O(4), was extracted from Leucas Urticifolia, a wild Lamiaceae herb distributed in the Punjab, Baluchistan, Sindh and the Rajputana desert of Pakistan. The plant is utilized for various medicinal applications by the local community. The title compound is based on the pimarane-diterpene skeleton. The mol-ecule exhibits an ep-oxy ring fused to momilactone-A, leading to a penta-cyclic mol-ecular structure. The absolute configuration was assigned by comparison with the crystal structure of momilactone, but needs further verification. The crystal structure is governed by four inter-molecular hydrogen-bond inter-actions of the C-H⋯O type.

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