The geometries and energies of the conformers of oxocane, the isomeric diand trioxocanes, and of 1,3,5,7-tetroxocane were calculated by molecular mechanics. A boat-chair conformation was preferred by all molecules. From the preference of oxygen in the boat-chair conformations of oxocane (position 3 over 1 over 4) the preferred boat-chair form of all other oxocanes can be derived. The results ar...

The title compound, C(20)H(30)O(4), is a dolabrane diterpenoid isolated from Ceriops tagal, in which one of the three fused cyclo-hexane rings adopts a half-chair conformation and the other two are in the standard chair conformations. The hy-droxy-methyl-idene substituent is attached to the half-chair cyclo-hexane. An intra-molecular O-H⋯O hydrogen bond generate an S(6) ring motif. In the cryst...

The six-membered thia-zine ring in the title compound, C16H15NOS, adopts a half-chair conformation, with the S atom forming the back of the chair. The base of the chair has a slight twist reflected in the r.m.s. deviation (0.0756 Å) of those five atoms from the plane defined by them. The phenyl substituents are almost perpendicular to each other [dihedral angle 87.06 (9)°]. In the crystal, mol-...

The title compound, C(15)H(22)O(4), consists of two trans-fused six-membered rings and a trans-fused five-membered γ-lactone. The ep-oxy and hydroxyl groups are α-oriented. The cyclo-hexane rings adopt half-chair and chair conformations and the lactone ring is in an envelope conformation. The mol-ecular structure is stabilized by one O-H⋯O and three C-H⋯O intra-molecular hydrogen bonds.

BACKGROUND Various water clusters including hexamers, heptamers, octamers, decamers and 1D or 2D infinite water chains in a number of organic and inorganic-organic hybrid hosts, have been reported. RESULTS {[Cu(pydc)(amp)].3H2O}n has been hydrothermally synthesized and characterized by elemental analysis and by IR spectroscopy. A wide range of hydrogen bonds (of the O-H...O, N-H...O and N-H.....

The title compound, C(26)H(36)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), wich was isolated from the chloro-form extract of the aerial parts of Anvillea radiata. The mol-ecule is built up from fused five- and ten-membered rings with the meth-oxy-phenyl-piperazine group as a substituent. ...

The title compound, C(20)H(19)Br(2)NO, shows a chair-chair conformation for the aza-bicycle with an equatorial disposition of the 4-bromo-phenyl groups [dihedral angle between the aromatic rings = 16.48 (3)°]. In the crystal, a short Br⋯Br contact [3.520 (4) Å] occurs and the structure is further stabilized by N-H⋯O hydrogen bonds and C-H⋯O inter-actions.

In the title compound, C29H37NO3 {systematic name: (E)-1-(4-meth-oxy-phen-yl)ethanone O-[(1R,4aS,10aR)-7-isopropyl-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octa-hydro-phenanthrene-1-carbon-yl]oxime}, a new derivative of de-hydro-abietic acid, the two cyclo-hexane rings exhibit a trans-ring junction and are in chair and half-chair conformations. The C=N double bond exhibits an E conformation.

In the title compound, C40H50O6, a symmetrical steroid oxalate diester, the dihedral angle between the CO2 planes of the oxalate linker is 61.5 (5)° and the C-C bond length is 1.513 (6) Å. The steroid B, C and D rings adopt half-chair, chair and envelope conformations, respectively, in both halves of the mol-ecule, which adopts an overall shallow V-shaped conformation. In the crystal, mol-ecule...

In the title sinomenine derivative, C(26)H(28)FNO(4)·1.5H(2)O, the dihedral angle between the two aromatic rings is 55.32 (6)°. The N-containing ring has an approximate chair conformation, while other two rings have approximate envelope and half-chair conformations. One water mol-ecule is located on a twofold symmetry axis. In the crystal, the water mol-ecules form O-H⋯O and O-H⋯N hydrogen bond...