Isolation and crystal structure of marcanine A from Polyalthia plagioneura.

Marcanine A was isolated from the stems of Polyalthia plagioneura as light yellow crystals. The molecular and crystal structures have been determined by 1D,2D-NMR and X-ray diffraction analysis. It crystallizes in the triclinic system, space group P-1 with a = 5.

1-(5-Hydroxy-7-methoxy-2,2-dimethyl-2H-chromen-6-yl)ethan-1-one.

The title chromene, C(14)H(16)O(4), was isolated from the stems of Polyalthia plagioneura Diels. The mol-ecular structure is stabilized by an intra-molecular O-H⋯O hydrogen bond, which generates an S(6) ring. In the crystal, the mol-ecules are linked by C-H⋯O inter-actions, generating [010] chains.

[Preparation of coated iron nanoparticles for reduction of trichloroethylene].

Nanoscale alpha-Fe particles with size of about 80 nm were prepared with a microemulsion-coated method. The results demonstrated that this kind of iron particles could exist stably in the air for 7 d compared with nanoscale iron particles prepared by liquid-phase and microemulsion methods. The removal rate of trichloroethylene with an initial concentration of 10 mg x L(-1) can reach 90% in 700 h.

[Study on the chemical constituents of liposoluble steroidal and triterpenoid compounds from the stem and bark of Macaranga hemsleyana].

Objective: to research the chemical constituents of the liposoluble compounds from the stem and bark of Macaranga hemsleyana Pax & Hoffm.

Methods: Five compounds were obtained by silica chromatography and preparative TLC from the stem and bark of Macaranga hemsleyana Pax & Hoffm., and the chemical structures of these compounds were identified by modern spectroscopy as well as physico-chemical analysis.