The title compound, C16H25Cl2N, 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 the essential oil of the Atlas cedar (Cedrus Atlantica). The mol-ecule is built up from fused six- and seven-membered rings linked to two three-membered rings. The six-membered ring shows a half-chair conformation, whereas the seven-mem...

a method is described by which it is possible to determine the high barrier to ring inversion and hindered rotation by neat racemization of optically active compounds when the racemization is caused by ring inversion or hindered rotation. the method is based preparation of sufficiently pure enantiomers, mainly by chromatography on swollen microcrystalline triacetylcellulose (tac). by this techn...

THE TITLE COMPOUND [SYSTEMATIC NAME: (1S,4S,5R,7S,8S,9R,10R,11S,13S,14S,16S,17R)-N-methyl-8,14-dihy-droxy-1,16-tri-meth-oxy-4-(meth-oxy-methyl-ene)aconitane], C(24)H(39)NO(5), was isolated from the roots of Aconitum carmichaelii Debx., which is known as 'Chuanwu' in Chinese traditional herbal medicine. The mol-ecule has an aconitane carbon skeleton with four six-membered rings and two five-memb...

There are two independent mol-ecules in the asymmetric unit of the title compound, C(30)H(44)O(5). They comprise a triterpenoid skeleton of five six-membered rings and a five-membered lactone ring. The five six-membered rings are all trans-fused. In both independent mol-ecules the D rings adopt a slightly distorted half-chair conformation due the presence of the lactone ring while the other fou...

The formation of ?-aromatic circuits along a grossly warped nanographene, C80H30, containing five- and seven-membered rings inserted into six-membered mesh, reveals global ?-circuits at the edge backbone.

The mol-ecule of the title compound, C(20)H(32)O(4), is built up from three fused five-membered, six-membered and seven-membered rings. The five-membered ring has an envelope conformation, whereas the six- and seven-membered rings have chair conformations. The crystal structure is stabilized by strong inter-molecular O-H⋯O hydrogen bonds, forming a three-dimensional network. The absolute config...

The title compounds, C17H20O2 (1) and C17H18O2 (2), are allyl-ated caged compounds. In (1), the carbon atoms bearing the allyl groups are far apart [2.9417 (17) Å], hence the expected ring-closing metathesis (RCM) protocol failed to give a ring-closing product. When these carbon atoms are connected by a C-C bond as in (2), the distance between them is much smaller [1.611 (3) Å] and consequently...

The title compound, C(26)H(39)NO(7), which was isolated from Delphinium anthriscifolium var. majus, has a lycoctonine carbon skeleton containing four six-membered rings (A, B, D and E) and three five-membered rings (C, F and G). Rings A, B and E adopt chair conformation, while ring D adopts a boat conformation. Rings C and F adopt envelope conformations.

The title compound, C(12)H(19)IO(5), is the ortho-rhom-bic polymorph of a previously reported monoclinic form [Krajewski et al. (1987 ▶). Bull. Pol. Acad. Sci. Chem.35, 91-102]. The dihedral angles between the six-membered ring and the two five-membered rings are 67.66 (14) and 71.79 (13)°, whereas the dihedral angle between the five-membered rings is 74.41 (12)°, indicating that all three ring...

The title compound, C(17)H(18)NO(+)·I(-), is an adduct resulting from an intra-molecular Diels-Alder reaction of methallyl chloride with 3,4-dihydro-1-furylisoquinoline. The cation comprises a fused penta-cyclic system containing three five-membered rings (dihydro-pyrrole, dihydro-furan and tetra-hydro-furan) and two six-membered rings (tetra-hydro-pyridine and benzene). The five-membered rings...