Synthesis and structure-activity relationship of kujigamberol B, a dinorlabdane diterpenoid isolated from an ancient Kuji amber.

The versatile methodology was developed for synthesizing kujigamberol B, a dinorlabdane diterpenoid isolated from the methanol extract of Kuji amber. A highly efficient intramolecular cyclization is followed by a Sonogashira-coupling reaction during the total synthesis. The synthesized compounds were evaluated for the growth-restoring activity against the mutant yeast (zds1Δ erg3Δ pdr1Δ pdr3Δ) and for the degranulation of RBL-2H3 cells. We found that in both activities, primary alcohol and secondary alcohol analogs are as active as kujigamberol B.

Cochlioquinone derivatives produced by coculture of endophytes, Clonostachys rosea and Nectria pseudotrichia.

Three new meroterpenoid derivatives, furanocochlioquinol (1) and furanocochlioquinone (2), as well as nectrianolin D (3), together with two known biogenetically related compounds 4 and 5 were isolated from a mixed culture of two mangrove-derived fungi, Clonostachys rosea B5-2 and Nectria pseudotrichia B69-1. The structures of 1-3 were deduced based on the interpretation of HRMS and NMR data. Compounds 1-5 exhibited cytotoxicity against human promyelocytic leukemia (HL60) cells with IC50 values ranging from 0.47 to 10.16 µM.

HPLC retention behaviors of poly-aromatic-hydrocarbones on Cu(II)-octabromotetrakis(4-carboxyphenyl)porphine derivatives-immobilized aminopropyl silica gels in polar and non-polar eluents.

As one of approaches of developing novel HPLC stationary phases, we prepared Cu-octabromotetrakis(4-carboxyphenyl)porphine derivative-immobilized silica gels (Cu-OBTCPP(D)), and evaluated the availability of the resultant Cu-OBTCPP(D) as a stationary phase for separation of poly-aromatic-hydrocarbons (PAHs) and their related compounds. A Cu-OBTCPP(D) column was revealed to have an ability to separate simple PAHs and be useful as a stationary phase in both polar and non-polar eluents. The retention property of the Cu-OBTCPP(D) column was evaluated in various comparative experiments using commercially available columns. In comparison with 2-(1-pyrenyl)ethyl dimetylsilyl silica gel column (PYE column) regarding the retention behavior for PAHs etc., the Cu-OBTCPP(D) column showed stronger interactions involving pi electron in non-polar eluent than PYE column. In comparison with a pentabromobenzyloxy propylsilyl silica gel column (PBB column) regarding the influence of bromination, the Cu-OBTCPP(D) column was affected differently from the PBB column. In comparison with nitrophenylethyl silica gel column (NPE column) regarding the retention behavior for compounds having a dipole in a non-polar eluent, the Cu-OBTCPP(D) column showed electrostatic interactions such as dipole-dipole interaction equivalent to or larger than the NPE column.

Effect of octabromination of a tetrakis(4-carboxyphenyl)porphine derivative bound to silica gels on HPLC retention behaviors of polyaromatic hydrocarbons.

The effect of bromination of Cu-porphyrin-derivative-immobilized silica gels (Cu-TCPP(D)) was examined by comparing the retention behaviors of polyaromatic hydrocarbons (PAHs) on Cu-TCPP(D) and Cu-octabromotetrakis(4-carboxyphenyl)porphine-derivative-immobilized silica gels (Cu-OBTCPP(D)) columns. It was revealed that bromination affects strongly the pi-pi electron interactions caused from hydration energy in a polar eluent (80% methanol) possibly as a result of a destruction of planar structure of porphine-ring by bromination. It was also revealed that bromination enhances pi-d interactions as well as the pi-pi electron interactions in a broad sense (e.g., dispersion forces) in a non-polar eluent (n-hexane). However, the bromination did not exert much influence on electrostatic interactions caused from polarization of mono-halogenated benzenes.