Bispuupehenone from the South Chinese Sea sponge Dysidea sp.

Bispuupehenone, C42H54O6, formally results from dimerization of puupehenone, which is constructed of sesquiterpene and benzene units. Bispuupehenone was isolated from the South China Sea sponge Dysidea sp. and the single-crystal X-ray diffraction analysis confirmed the previously reported structure. The molecule is located on a twofold axis and the dimerization forms two fused dibenzopyran systems related by symmetry. In the asymmetric unit, the two cyclohexane rings adopt chair conformations, while the two pyran rings adopt half-chair conformations. The relative stereochemistry and configurations for the ring junctions are in agreement with the structure reported previously.

Bispuupehenone, C 42 H 54 O 6 , formally results from dimerization of puupehenone, which is constructed of sesquiterpene and benzene units. Bispuupehenone was isolated from the South China Sea sponge Dysidea sp. and the single-crystal X-ray diffraction analysis confirmed the previously reported structure. The molecule is located on a twofold axis and the dimerization forms two fused dibenzopyran systems related by symmetry. In the asymmetric unit, the two cyclohexane rings adopt chair conformations, while the two pyran rings adopt half-chair conformations. The relative stereochemistry and configurations for the ring junctions are in agreement with the structure reported previously.
Bispuupehenone from the South Chinese Sea sponge Dysidea sp.
S. Qin, L. Shi, J. Li and Y.-W. Guo Comment Bispuupehenone (I) was firstly isolated from Pacific marine sponge Heteronema sp. (Amade et al., 1983), and was considered to be generated from co-occurring puupehenone (II) (Fig. 1) by in vitro oxidative coupling. The benzopyrane structure for the dimer is deduced by the comparison of its UV spectrum data with those of a simple dibenzofuran and a simple benzopyran. Although compound (II) and its derivatives have been reported to display a wide range of important biological activities, including antiviral, antifungal, antimalarial, and antitumor activities (Barrero et al., 1998(Barrero et al., , 1999Longley et al., 1993;Castro et al., 2004;Ciavatta et al., 2007;Kohmoto et al., 1987;Takamatsu et al., 2003), the biological properties of (I) have been seldom reported. Synthesis and semi-synthesis of puupehenone and its derivatives have been published (Hamann, 2003); Alvarez-Manzaneda et al., 2005, 2007.
As part of our research project on the study of the South China Sea marine organisms, a sample of the sponge Dysidea sp. was collected off the Lingshui Bay, Hainan Province, China, and was chemically investigated. Bispuupehenone, (I), was isolated and crystallized from the Et 2 O-soluble fraction of the acetone extract of the animal, and the structure of (I) was firstly elucidated by spectroscopic methods, NMR, UV and MS, and eventually confirmed through X-ray diffraction analysis. Herein, we report the X-ray structure of (I).
The projection of bispuupehenone is shown in Figure 2. In the structure, two puupehenone moieties are connected through two O atoms and a C-C bond between benzene rings, forming a benzopyran moiety at the midpoint of the axial symmetric molecule. Rings A and B of (I) are in chair conformations, while rings C and D adopt half-chair conformations. Moreover, the trans junction between rings A/B and the cis junction between rings B/C are in agreement with the structure reported previously.
Bispuupehenone was tested for the inhibitory activities against hPTP1B (human protein tyrosine phosphatase 1B), a key target for the treatment of Type-II diabetes and obesity, and showed excellent inhibitory effect with IC 50 value of 0.98 mg ml -1 . Other bioassays, such as antibacterial and anti-inflammatory, are currently ongoing. suitable for X-ray analysis were obtained by slow evaporation from a chloroform solution.

Refinement
The non-H atoms were located in successive difference Fourier syntheses. The final refinements were performed by fullmatrix least-squares methods with isotropic thermal parameters for all non-H atoms. Hydroxyl H atom H2 was found in a difference map and freely refined with an isotropic displacement parameter. Other H atoms were placed in calculated positions and included in the final refinement in the riding model approximation, with displacement parameters derived from the parent atoms to which they are bonded. In the absence of significant anomalous dispersion effects, 1571 measured Friedel pairs were merged and the absolute configuration was arbitrarily assigned.