Two New Compounds from Goniothalamus Cheliensis Hu

Goniothalamus cheliensis Hu (Annonaceace) is a small tree or shrub in Yunnan Province, southwest of China. Acetogenins, styryllactones and alkaloids1-3 from the genus were reported in the previous literature and many of them showed strong cytotoxic activities against a number of human cancer cell lines4. The titled plant has been the subject of our investigation due to the impressive cytotoxicity of its organic extract against mouse lymphocytic leukemia cells in preliminary pharmacological s…     

微波消解-浊点萃取-火焰原子吸收光谱法测定空心胶囊中铬含量

研究了微波消解-浊点萃取-火焰原子吸收光谱法(FAAS)测定空心胶囊中痕量铬的方法。空心胶囊通过微波消解,以二乙基二硫代氨基甲酸钠(DDTC)为络合剂络合消解液中铬(Ⅵ),非离子表面活性剂Triton X-114为萃取剂,结合FAAS测定空心胶囊中痕量铬,与《中国药典》(2010版)检测方法具有较好一致性。考察了溶液的pH值、络合剂和表面活性剂浓度、平衡温度和时间等条件对浊点萃取效果的影响。在最优条件下,铬(Ⅵ)线性范围为0～10μg/mL,检出限(3σ)为7.6ng/mL,相对标准偏差为1.5%(n=10),回收率在95%～102%之间。方法灵敏度高,重复性好,适合于胶囊中铬的日常检测。     

Synthesis and Structure of E-2-(2,4,6-tri tert butylphenylphosphinyl)-2-〔N-(tert-butyldimethylsilyl)-N-(p-chrolophenyl)〕amino-1-(2,4,6-tri tert-butyl-phenyl)phosphacthylene

1　INTRODUCTIONItwaswellknown thatelementsofthesecondary and higherrow are in generaldifficulty to form multiplebondsin which apπ hybridized stateisinvolved〔1〕.Thus,simple compounds containing multiple phosphorus carbon bonds,such as methyl dynephosphine( HC≡P) 〔2 - 3〕 and methylenephosphine( H2 C=PH〔4〕,are notstableat room temperature.Three methods to stabilize compounds containing double ormultiple bond involving phosphorusatom in the pπ hybridized state are often used.The f…     

Site-specifically Hydrolytic Cleavage of Oxidized Insulin B Chain With Cu(II) Ion

Selectively chemical cleavage of peptides and proteins is one of the most important reactions in both chemical and biochemical processes. Over the past decade, the interaction of palladium(II) complexes with methionine, cysteine and histidine-containing peptides and proteins and the hydrolytic cleavage of the corresponding amide bond by Pd(II) complexes have been extensively studied1-13. However, reports concerning the directly selective hydrolysis of peptides and proteins with other simple …     

A New ent-Kaurane Diterpenoid from Isodon enanderianus

Isodon enanderianus (Hand. -Mazz.) H. W. Li, has been used in folk medicine as anti-inflammatory and detoxified agent1. The Isodon genus is known to be rich in ent-kaurane diterpenoids, a series of new ent-kaurane diterpenoids have been isolated from the dried leaves of I. enanderianus2-4. In order to find more biologically active substances, we have carefully investigated the chemical constituents of I. enanderianus collected in Shiping county of Yunnan province, and as a result, enanderi…     

Photochemical Reduction of Aromatic Imines by 2-Phenyl-N, N-dimethylbenzimidazoline

Reduction of C=N double bonds has been recognized as an important reaction both in organic chemistry and bio-chemistry1. Hantzsch 1,4-dihydropyridine (HEH, one of NADH model compounds) has been reported as a reductive reagent for imines2. However, application of dihydropyridines as practical reducing reagents in organic synthesis is limited because of their instability3. Like NADH models, 2-phenyl-N, N-dimethylbenzimidazoline (PDMBI) is an efficient electron and hydrogen donor (Eox = 0…     

Retention Behaviors of Uronic Acid-containing Polysaccharides and Neutral Polysaccharides in HPGPC

The determination of molecular weights (Mw) of polysaccharides has served as an important process since the physical properties of the polysaccharides are closely related to their Mw and/or molecular weights distribution (MWD). For Mw and MWD determinations, high performance gel permeation chromatography (HPGPC) has gained wide acceptance as a preferred method due to its high sensitivity, speed and reproducibility. In chromatography, it is well known that the molecular weights are determ…     

New conversion of Friendlnder reaction of 3-amino-1H-benzo[f]chromene-2-carbonitriles with cyclohexanone

Two different skeletons of heterocyclic compounds,quinoline and quinazolinone analogs could be obtained by a novel one-pot synthesis from substituted 3-amino-1 H-benzo[f]chromene-2-carbonitrile derivatives and cyclohexanone in DMF in the catalyst of anhydrous zinc chloride under reflux.A plausible mechanism was proposed.     

Hybrid Composite of Polyaniline Containing Carbon Nanotube

Among various conducting polymers, polyaniline (PANI) is a unique and promising candidate for practical applications because it is not only highly stable in air and in some solvents, but also exhibits dramatic changes in its electronic structure and physical properties in protoactivate state1,2,3. The carbon nanotubes (CNTs) have been proven to possess exotic properties, such as high mechanical strength, flexibility and electric conductivity. The study of carbon-based nanostructures and ma…     

One-Pot Synthesis of N-Boc-2, 5-bis(trimethylsilyl)pyrrolidine

Since Daly reported the structure of epibatidine and its potent analgesic activity in 19921, study on the synthesis of epibatidine and its derivatives and relationships between the structure and activity of epibatidine has received much attention2. During the course of our research for the synthesis of epibatidine derivatives, N-boc-2, 5-bis(trimethylsilyl)pyrrolidine 4 was used as the key intermediate to construct the skeleton of epibatidine via the 1, 3-dipolar cycloaddition (Scheme 1). Ac…