The title compound, C(22)H(28)O, was isolated from the aerial part of Inula viscosa- (L) Aiton [or Dittrichia viscosa- (L) Greuter]. The cyclo-hexene ring has a half-chair conformation, whereas the cyclo-hexane ring displays a chair conformation being substituted at position 2 by a 3-(4-methyl-phen-yl)prop-2-enoyl group. In the crystal, weak inter-molecular C-H⋯O hydrogen bonds link mol-ecules ...

In the title compound, C(16)H(17)N(3)O(4), the six-membered N-containing ring adopts a half-chair conformation. One C atom of the five-membered ring is disordered over two sites, with occupancy factors of ca 0.67 and 0.33. The major pyrroline component adopts a half-chair conformation. Inter-molecular C-H⋯O hydrogen bonds forming centrosymmetric dimers are observed in the crystal.

The previously unobserved chair conformation of C-methylcalix[4]resorcinarene has been found in three different supramolecular solids, prepared by hydrothermal synthesis. The existence of the chair, crown and flattened cone conformations of C-methylcalix[4]resorcinarene demonstrates the dependence of the molecular conformation upon the templating molecules, and upon the specifics of the crystal...

In the title compound, C25H25ClO2, the C ring adopts a chair conformation, while the B ring approximates a half-chair conformation. The five-membered ring D has a twist con-form-ation on the C-C bond fused with the C ring. Aromatic rings A and E are not coplanar, as evidenced by the dihedral angle of 7.51 (1)°. In the crystal, O-H⋯O hydrogen bonds form a double chain along the ab plane inter-co...

The title compound, C(29)H(37)NO(2), crystallized with two independent mol-ecules in an asymmetric unit in which the conformation of the cyclo-hexyl ring of the pregnene moiety bonded to the 3α-(1,3-dioxoisoindolin-2-yl)- ring system differs: in one mol-ecule it is in a chair conformation, while in the other it exhibits a half-chair conformation. The other six-membered rings in the pregnene moi...

In this work, the optimization calculations were carried out on quetiapine hemifumarat, 4, and its analogues, 1-5. These calculations were carried out using the B3LYP/6-31G(d) level of theory. The DFT calculations clarified a boat structure for dibenzothiazepine moiety of the molecule which piperazine moiety has a chair conformation. Thermal energies (E), enthalpies (H), and free energies (G) o...

The L-iduronic acid (IdoA) residue is a critically important structural component in heparan sulphate polysaccharide for the biological functions. The pyranose ring of IdoA is present in (1)C4-chair, (2)SO-skew boat, and less frequently, in (4)C1-chair conformations. Here, we analyzed the conformation of IdoA residue in eight hexasaccharides by NMR. The data demonstrate a correlation between th...

The title compound, C19H29NO4S, was synthesised from 9α-hy-droxy-parthenolide (9α-hy-droxy-4,8-dimethyl-12-methyl-ene-3,14-dioxatri-cyclo-[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 the plant Anvillea radiata. The mol-ecule is built up from two fused five- and ten-membered rings, with an additional ep-oxy ring system and a thio-mo...

The title compound, C(25)H(34)N(2)O(5), 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 mol-ecule contains a fused five- and ten-membered ring system. The ten-membered ring adopts an approximate chair-chair co...

In the title compound, C(22)H(21)N, the pyridine ring adopts a distorted boat conformation, while the adjacent pyran ring adopts a chair conformation; the heterocyclic rings make a dihedral angle of 40.1 (2)° with each other.