In the title mol-ecule, C(28)H(44)O, the two six-membered rings have a chair conformation and the two five-membered rings haveenvelope conformations. The crystal packing exhibits no short inter-molecular contacts. The absolute configuration was assigned to correspond with that of the known chiral centres in a precursor molecule, which remained unchanged during the synthesis of the title compound.

The title compound, C(23)H(35)BrO(3), synthesized by esterification and bromination of isosteviol, comprises a fused four-ring system. Two of the six-membered rings adopt a regular chair conformation, whereas the remaining six-membered ring is an unsymmetrical distorted chair. The stereochemistry at the two six-membered ring junctions is trans, while the five-membered ring adopts an envelope co...

The title compound, C(27)H(47)NO(3), is a (3-hydroxy-prop-yl)amide derivative of naturally occurring enanti-opure lithocholic acid (3α-hydr-oxy-5β-cholan-24-oic acid). The mol-ecule contains four fused rings: three six-membered rings in chair conformations and one five-membered ring in a half-chair form. The two terminal six-membered rings are cis-fused, while other rings are trans-fused. The s...

In the title compound, C(24)H(36)O(4) [systematic name: (20S)-3β-acet-oxy-16α-hydr-oxy-22,23-bis-nor-5α,17β-cholano(22-16)lac-tone], the three six-membered rings adopt classical chair conformations, while the five-membered rings are in envelope conformations. The ester group attached to ring A is in an equatorial position. Rings A/B, B/C and C/D are trans-fused, whereas rings D/E are cis-fused....

We predict the geometries, electronic properties, and aromaticity of thiophene analogues anti-kekulene with six to nine rings 1–4, together those cyclobutadithiophenes (CDTs) as reference compounds, using density functional theory calculations. Investigation simplest CDTs, reveals that local their is influenced by fused position (b- or c-bond) four-membered ring (4MR). A at b-position (b-TR) re...

The title compound, C(14)H(16)N(2)O, is a synthetic analogue of quinazolone alkaloids with pyrrilo, pyrido and azopino rings. The quinazolinic part of the mol-ecule is generally planar within 0.037 (3) Å; the eight-membered ring exhibits an inter-mediate conformation between the chair and boat forms as it is typical for cyclo-octene rings. An ethyl-ene group of the azopino ring is disordered ov...

THE TITLE COMPOUND [SYSTEMATIC NAME: (3bS,5aS,7R,8R,10aR,10bS)-7-meth-oxy-10b-methyl-3b,4,5,6,7,8,9,10,10a,10b,11,12-dodeca-hydro-5a,8-methano-5aH-cyclo-hepta-l[5,6]naph-tho[2,1-b]furan-7-methanol], C(21)H(30)O(3), was isolated from the beans of Coffea robusta. The mol-ecule contains five fused rings including a furan ring. The two six-membered rings are in chair conformations, but the third si...

The title compound, C(36)H(34)N(4)O(4)S(2), is a thio-glycoluril derivative, which bears two phenyl substituents on its convex face and two meth-oxy substituted o-xylylenes as sidewalls of the molecular clip. There is one half-mol-ecule in the asymmetric unit: a crystallographic twofold axis generates the complete molecule. The non-planar seven-membered rings adopt chair conformations, while th...

The title compound, C16H24Cl2O, was synthesized in three steps from β-himachalene (3,5,5,9-tetra-methyl-2,4a,5,6,7,8-hexa-hydro-1H-benzo-cyclo-heptene), which was isolated from essential oil of the Atlas cedar (cedrus atlantica). The asymmetric unit contains two independent mol-ecules with similar conformations. Each mol-ecule is built up from two fused seven-membered rings and an additional th...