In the title natural product, C(17)H(24)O(4), which is a very potent inhibitor of protein synthesis in mammalian cells, the five-membered ring displays an envelope conformation, whereas the two six-membered rings show different conformations, viz. chair and half-chair.

The title compound, C(25)H(33)FN(2)O(4), was synthesized from 9α-hy-droxy-parthenolide (9α-hy-droxy-4,8-dimethyl-12-methyl-ene-3,14-dioxatricyclo-[9.3.0.0(2,4)]tetra-dec-7-en-13-one), which was isolated from the chloro-form extract of the aerial parts of Anvillea radiata. The asymmetric unit contains two independent mol-ecules. In each mol-ecule, the ten-membered ring displays an approximative ...

The title compound, C25H34N2O5, was synthesized from 9α-hy-droxy-parthenolide (9α-hy-droxy-4,8-dimethyl-12-methylen-3, 14-dioxa-tri-cyclo-[9.3.0.0(2,4)]tetra-dec-7-en-13-one), which in turn was isolated from the chloro-form extract of the aerial parts of Anvillea radiata. The mol-ecule comprises a ten-membered ring fused to a five-membered ring with an additional ep-oxy ring system fused to the...

The title compound, C20H18O6, prepared from d-mannitol by a two-step procedure, is a functionalized fused bis-tetra-hydro-furan. In the central fragment, consisting of two fused tetra-hydro-furan rings, one O atom and its two adjacent C atoms, a methyl-ene and a bridgehead C atom, are disordered over two sets of sites with an occupancy ratio of 0.735 (9):0.265 (9). In the major component, the r...

The title compound, C(26)H(32)O(11), is composed of an α,β-unsaturated cyclo-hexa-none ring (A), two cyclo-hexane rings (B and C), a six-membered lactone ring (D) and tetra-hydro-furan ring (E). Ring A exists in a half-chair conformation with a C atom displaced by 0.679 (2) Å from the mean plane through the remaining five atoms. Ring B exists in a normal chair conformation. Both rings C and D e...

In the title compound, C(33)H(28)N(2)O(4), the central pyrrolidine ring adopts a half-chair conformation. Both the indolinone and indanone groups are twisted, with their five-membered rings adopting a half-chair and an envelope conformation, respectively. The two benzene rings and the mean plane of the indolinone and indanone groups make dihedral angles of 71.98 (10), 84.32 (10), 86.26 (9) and ...

In the title E isomer of the racemic compound, C37H32F2N2O2, the pyridinone ring adopts a twisted half-chair conformation with the N atom deviating by -0.355 (3) Å and with the methyl-ene C atom next to octa-hydro-indolizine moiety deviating by 0.415 (3) Å from the mean plane defined by other four atoms. In the octa-hydro-indolizine system, the pyrrolidine ring exhibits an envelope conformation...

In the title compound, C(18)H(22)Cl(3)NO(11), a novel derivative of l-idopyran-osiduronic acid, the six-membered ring adopts a chair conformation.

The title compound, C23H30N2O4, a di-Mannich base derived from 4-meth-oxy-phenol and cis-1,2-di-amine-cyclo-hexane, has a perhydro-benzimidazolidine nucleus, in which the cyclo-hexane ring adopts a chair conformation and the heterocyclic ring has a half-chair conformation with a C-N-C-C torsion angles of -48.14 (15) and -14.57 (16)°. The mean plane of the heterocycle makes dihedral angles of 86...

In the title compound, C(29)H(42)N(2)O(2), the heterocyclic ring has a twist conformation. The cyclohexane ring adopts a chair conformation. The dihedral angle between the aromatic rings is 32.74 (6)°. The mol-ecular conformation is stabilized by two intramolecular O-H⋯N hydrogen bonds with graph-set motif S(6). The crystal packing is stabilized by C-H⋯O and C-H⋯π inter-actions.