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acid dioctadecyl ester. MTT assay showed that 1 had weak inhibitory activity against growth of CNE-1 nasopharyngeal carcinoma cell line.Key word: brugnanin, mangrove, Bruguiera gymnorrhiza, MTT, CNE-1.Bruguiera gymnorrhiza is one of the ecosystemically important mangrove plants in the estuaries of Guangxi Zhuang Autonomous Region, China [1]. It has been used as folk medicine for the treatment of diseases such as fever, diarrhea, haemorrhage, inflammation, and malaria [2]. Previous natural products chemistry efforts on this plant species have yielded some structurally interesting natural products such as diterpenes [3,4], cyclic disulfides [5] and polydisulfides [6], and aromatic compounds [7]. As part of our investigations of bioactive compounds in mangrove plants indigenous to Guangxi Zhuang Autonomous Region, China, we examined the stem bark of B. gymnorrhiza collected from Shankou Town, Hepu County. As a result, we isolated and identified a previously unknown neolignan diacid ester, brugnanin (1), which possesses a unique syn-2,3-dihydrobenzofuran skeleton.The air-dried outer layer and inner layer of the stem bark of Bruguiera gymnorrhiza were extracted with 95% ethanol and partitioned with petroleum ether. The partition of petroleum ether was then subjected to silica gel column chromatography, and from the eluting fractions of 10% ethyl acetate in petroleum ether, brugnanin (1) was obtained.Brugnanin (1) was obtained as a white amorphous powder. The fast atom bombardment mass spectrum (FAB-MS) of 1 presented a quasi-molecular ion peak [M+H] + at m/z 891. The high resolution matrix-assisted laser desorption ionization mass (HRMALDI-MS) spectrum of 1 gave a quasi-molecular ion peak [M+Na] + at m/z 913.6549. Combined with other spectroscopic data, these mass data allowed us to establish the molecular formula C 56 H 90 O 8 , which has a calculated relative molecular weight of 890.6636.

The synthesis and characterization of orthophosphiniminium-arenesulfonate zwitterions 1a−1d, the corresponding sodium salts 3a−3d, methyl(pyridine)palladium-(II) complex 4a, and methyl(4-tert-butylpyridine)palladium-(II) 5a−5d complexes are reported. Complex 4a suffers from limited solubility in aromatic hydrocarbons, while 5a−5d are soluble in benzene and toluene. Complex 5a forms a tridentate orthopalladated species 6a upon heating to 80°C in toluene. Introduction of alkyl substituents on the phosphinimine phosphorus atom retards orthopalladation, and the ( n Bu) 3 P functionalized complex 5d does not undergo orthopalladation after heating at 80°C for 24 h. The Pd−C bond in the orthopalladated complex 6a is inert toward ethylene insertion. Complexes 5a−5d do not react with ethylene at 80°C and decompose to Pd 0 and zwitterions 1a−1d. ■ INTRODUCTIONInsertion polymerization of ethylene and propylene by early transition metal catalysts occurs on a vast scale. 1 Late transition metal catalysts have also been studied for olefin polymerization and oligomerization due to their different reactivity, branch formation, and generally reduced oxophilic nature. 2−5 This last feature is particularly important with regard to the insertion polymerization of functionalized olefins. Neutral palladium(II) complexes incorporating anionic ortho-phosphino-arenesulfonate (P-SO) ligands (Figure 1, A) have received considerable attention as versatile catalysts for ethylene polymerization to highly linear polyethylene (PE) 6 and the copolymerization of ethylene with a variety of functionalized monomers. 7 The combination of strong (phosphine) and weak (sulfonate) σ-donor groups in the P-SO ligand is thought to inhibit β-hydride elimination, thus eliminating chain walking and polymer branching. 1,8 The molecular weight (MW) and polymerization activity of the resulting polymers from these catalysts can be tuned by incorporation of different substituents (R) on the P-SO ligand 9 and by varying the labile ligand (L) attached to palladium, 10 but are generally low compared to other catalysts. 2

Diastereoselective addition of nitromethane to Boc-D-Phe-H in the presence of sodium hydride in diethyl ether/hexane containing 15-crown-5 and subsequent N,O-protection with 2,2-dimethoxypropane gave trans-oxazolidine in a diastereomeric ratio of >16:1. The oxazolidine was easily separated by column chromatography, which after Nef reaction was coupled to H-Leu-OtBu. The 8-step synthesis afforded (-)-bestatin in an overall yield of 24.7% after deprotection and ion exchange.

The title compound, C15H18NO3PS·C6H6, is a rare example of a crystallographically characterized exocyclic phosphiniminium–arene­sulfonate zwitterion, which crystallises as its benzene solvate. The crystal structure shows that the N atom is protonated and that the iminium H atom forms both intra- and inter­molecular hydrogen bonds to the single-bonded sulfonate O atom in an R 2 2(4) graph-set motif. The dihedral angle between the aromatic rings in the main molecule is 89.49 (8)°.