A one-pot procedure to prepare S-protected 4-iodothiophenols

By means of non-aqueous reduction of pipsyl chloride followed by treatment with K2CO3 and then reacting with acetyl chloride or benzyl chloride, S-acetyl/benzyl -4-iodothiophenols were obtained in a one-pot procedure with yield as high as 90%. These S-protected arenethiols are very important intermediates to synthesize self-assembled molecular wires.

Studies on the adduct reaction of disubstituted benzenes with ion system of acetone in gas phase

Ion - molecule reactions of disubstituted benzene with ion system of acetone and deuterium - labelled acetone under chemical ionization conditions were examined and the fragmentation reactions of the adduct ions formed by the ion - molecule reactions were studied using collision - induced dissociation (CID) technique. It was found that the electron - releasing groups favored the adduct reactions, whereas the electron - withdrawing groups did not. The position and properties of substituted groups affected the relative abundance of the adduct ions. The fragmentation reaction of the adduct ion formed by ortho - phenylenediamine with acetyl ion was similar to the reductive alkylation reaction of amine in condensed phase.

Studies on the solution structures of lanthanide(III) complexes of DTPA-BIN by NMR

The solution structures of diamagnetic lanthanide (III) complexes of DTPA-BIN (Ln = La, Y, Lu, Sc) have been investigated by H-1 NMR, C-13 NMR and 2D NMR. For each complex, two or more species of asymmetric conformations with little distinction were identified at room temperature. And their solution structures vary with the radius of the central metals. NMR spectra support the hypothesis that Sc3+ with smaller radius formed an eight-coordinated structure with DTPA-BIN, La3+ with larger radius formed nine- or ten-coordinated structures with DTPA-BIN, and Y (DTPA-BIN) and Lu (DTPA-BIN) had nine-coordinated solution structures. The solution structure of Gd (DTPA-BIN) was obtained from the similarity of radius between Gd3+ and Y3+, which is a nine-coordinated structure formed by three nitrogens, three acetate oxygens, two acetyl oxygens, one water molecule and a gadolinium(III) cation.

Electroluminescent properties of the Tris-(acetylsalicylate)-terbium (Tb(AS)(3))

The solubility of [Tris-(acetylsalicylate)-terbium] [Tb(AS)(3)] is improved to a greater extent than [Tris-(salicylate)-terbium] [Tb(Sal)(3)] following introduction of a flexible acetyl group. Th3+ binds with acetylsalicylate in solution at low pH value and the resultant Tb(AS)(3) has good solubility in chloroform. A Green EL device with the structure ITO/PVK/PVB:PBD: Tb(AS)(3)/ PBD/Al has been fabricated based on soluble Tb(AS)(3), in which Tb(AS)(3) was first used as an emissive center doped with PVK and PBD. The hole-transporting layer and the emissive layer were formed by spin coating. The device exhibited a highly pure characteristic green light of Tb3+. (C) 2001 Elsevier Science B.V. All rights reserved.

Fragmentation reactions of adduct ions [M+CH3CO](+) of isomeric phenylenediamines

The dissociation routes of the adduct ions [M+CH3CO](+) formed by ion-molecule reaction of isomeric phenylenediamines with acetyl ion from acetone under chemical ionization condition were investigated by using collision-induced dissociation (CID) technique performed at ion kinetic energies of 40eV. The adduct ions are intermediate ion-neutral complexes.

Cobalt(II)hexacyanoferrate film modified glassy carbon electrode for construction of a glucose biosensor

An amperometric glucose biosensor was constructed based on a glassy carbon electrode modified with a Cobalt(II)hexacyanoferrate film which catalyzes electroreduction of hydrogen peroxide. Gelatin was used as immobilization matrix. Interference could be effectively eliminated by the combination of low detection potential with a Nafion coating. A low applied potential can avoid oxidation of interferences such as ascorbic acid, uric acid, p-acetyl-aminophenol, etc.. Nafion coating prevents interferences from access to the electrode surface by electrostatic repulsion. A wide linear range of detection was obtained. Analytical performance parameters are given and kinetic analysis discussed.

Gas-phase ion-molecule reactions of C-60 and theoretical studies of [C60C2H3O](+) adduct cations

Gas-phase ion-molecule reactions of buckminsterfullerene (C-60) with the acetyl cation CH3-C-+=O (m/z 43) and formylmethyl cation (CH2)-C-+-CH=O (m/z 43, or oxiranyl cation), generated from the self-chemical ionization of acetone and vinyl acetate, respectively, were studied in the ion source of a mass spectrometer. Adduct cations [C60C2H3O](+) (m/z 763) and protonated C-60, [C60H](+) (m/z 721), were observed as the major products. AM1 semiempirical molecular orbital calculations on the possible structures, stabilities and charge locations of the isomers of the adducts [C60C2H3O](+) were carried out at the restricted Hartree-Fock level. The results indicated that the sigma-addition product [C-60-COCH3](+) is the most stable adduct for the reaction of C-60 with CH3-C-+=O rather than that resulting from the [2+2] cycloaddition. The [2+3] cycloadduct and the sigma-adduct [C60CH2CHO](+) might be the most possible coexisting products for the reactions of C-60 with (CH2)-C-+-CH=O or oxiranyl cation. Other [C60C2H3O](+) isomers are also discussed. (C) 1997 by John Wiley & Sons, Ltd.

GAS-PHASE ACETYLATION OF C-60 AND C-70 BY ION/MOLECULE REACTIONS

Gas phase reactions of C-60 and C-70 with the ion system of acetone under chemical ionization conditions have been studied. C-60 and C-70 can react with acetyl and oxonium ions, which come from self-chemical ionization of acetone, to form adduct ions. In addition, C-60 and C-70 can accept protons to produce protonated ions. C-70 is more active in the above reactions than C-60 because of its stronger gas-phase basicity. A sigma-bond between C-60 and an acyl carbon atom can be formed to produce stable acetylated C-60 ions. The above results may be relevant to the acetylation reactions of C-60 in the condensed phase.

MOSSBAUER-EFFECT STUDIES ON SOME BIOINORGANIC COMPLEXES OF EUROPIUM

The bioinorganic complexes of europium with N-acetyl-DL-alanine, N-acetyl-DL-valine, and DL-alanyl-DL-alanine have been synthesized and the Mossbauer spectra at room temperature have been measured for these solid state complexes. The Mossbauer parameters indicate that the water molecules in these complexes are not directly linked to the central europium ion and are outside the coordination sphere of europium and biological ligands, and that the chemical bond between the europium ion and the ligands may be predominantly ionic in character, with the possibility of partial covalent contribution.

THERMAL DECOMPOSITIONS OF SOME BIOINORGANIC COMPLEXES OF EUROPIUM

Thermogravimetric and derivative thermogravimetric investigations for three kinds of bioinorganic complexes of europium with N-acetyl-DL-alanine, N-acetyl-DL-valine and DL-alanyl-DL-alanine have been performed. It was found that the water molecules in these solid state complexes are not directly coordinated to the europium ion and that there may be three or four steps in the thermal decomposition process of these complexes after dehydration. The possible thermal decomposition reactions of these bioinorganic complexes have been suggested and discussed.

Flavanol derivatives from Rhizophora stylosa and their DPPH radical scavenging activity

A new acetylated flavanol, 3,7-O-diacetyl (-)-epicatechin (3), and seven known flavanol derivatives, (-)-epicatechin (1), 3-O-acetyl (-)-epicatechin (2), 3,3 ',4 ',5,7-O-pentaacetyl (-)-epicatechin (4), (+)-afzelechin (5), (+)-catechin (6), cinchonain Ib (7), and proanthocyanidin B2 (8), were isolated from the stems and twigs of the mangrove plant Rhizophora stylosa and identified. The crude extract, the different fractions and all of the purified compounds were evaluated for DPPH radical scavenging activity.

A fibrinogen-related protein from bay scallop Argopecten irradians involved in innate immunity as pattern recognition receptor

The family of fibrinogen-related proteins (FREPs) is a group of proteins with fibrinogen-like domains. Many members of this family play important roles as pattern recognition receptors in innate immune responses. The cDNA of bay scallop Argopecten irradians FREP (designated as AiFREP) was cloned by rapid amplification of cDNA ends (RACE) method based on the expressed sequence tag (EST). The full-length cDNA of AiFREP was of 990 bp. The open reading frame encoded a polypeptide of 251 amino acids, including a signal sequence and a 213 amino acids fibrinogen-like domain. The fibrinogen-like domain of AiFREP was highly similar to those of mammalian ficolins and other FREPs. The temporal expression of AiFREP mRNA in hemolymph was examined by fluorescent quantitative real-time PCR. The mRNA level of scallops challenged by Listonella anguillarum was significantly up-regulated, peaked to 9.39-fold at 9 h after stimulation, then dropped back to 4.37-fold at 12 h, while there was no significant change in the Micrococcus luteus challenged group in all periods of treatment. The function of AiFREP was investigated by recombination and expression of the cDNA fragment encoding its mature peptide in Escherichia coli Rosetta gami (DE3). The recombinant AiFREP (rAiFREP) agglutinated chicken erythrocytes and human A, B, O-type erythrocytes. The agglutinating activities were calcium-dependent and could be inhibited by acetyl group-containing carbohydrates. rAiFREP also agglutinated Gram-negative bacteria E. coli JM109, L anguillarum and Gram-positive bacteria M. luteus in the presence of calcium ions. These results collectively suggested that AiFREP functions as a pattern recognition receptor in the immune response of bay scallop and contributed to nonself recognition in invertebrates, which would also provide clues for elucidating the evolution of the lectin pathway of the complement system. (C) 2008 Elsevier Ltd. All rights reserved.

N-acetylchitooligosaccharide is a potent angiogenic inhibitor both in vivo and in vitro

N-Acetylchitooligosaccharide (N-acetyl-COs) was prepared by N-acetylation of chitooligosaccharide (COs). In vitro study using human umbilical vein endothelial cells (HUVECs) revealed that both N-acetyl-COs and COs inhibited the proliferation of HUVECs by inducing apoptosis. Treatment of HUVECs by N-acetyl-COs resulted in a significant reduction of density of the migration cells and repressed tubulogenesis process. The antiangiogenic effects of the oligosaccharides were further evaluated using in vivo zebrafish angiogenesis model, and the results showed that both oligosaccharides inhibited the growth of subintestinal vessels (SIV) of zebrafish embryos in a dose-dependent manner, as observed by endogenous alkaline phosphatase (EAP) staining assay. In contrast, no cytotoxicity was found when treating the NIH3T3 and several other cancer cells with the oligosaccharides. Our results also confirmed the antiangiogenic activity of N-acetyl-COs was significantly stronger than the parent oligosaccharide, COs. (c) 2007 Published by Elsevier Inc.

三种海洋红藻和两株放线菌次级代谢产物研究

海洋是一个巨大的天然产物宝库，约占地球表面积70%的海洋蕴藏着80%的生物资源。由于海洋生态环境的特殊性，导致海洋生物能够产生大量结构独特多变和活性特殊多样的代谢产物。我国海域辽阔，海洋资源丰富，为寻找结构新颖、生理活性独特的先导化合物，加强对海洋资源的开发利用，本论文对中国沿海的三种海洋红藻和两株放线菌次生代谢产物以及生物活性进行研究，为新药研究与开发提供模式结构和药物前体。 对红藻似瘤凹顶藻Laurencia similis乙酸乙酯萃取物进行分离纯化，从中得到单体化合物35个，通过波谱学方法（IR、MS、NMR等）鉴定了他们的结构。分别为：2, 2, 5, 5, 6, 6-sixibromo-3, 3-bi-1H-indole (1)，3,5-dibromo- 1-methyl-indole (2)，3',5',6,6'-tetrabromo-2,4-dimmethyldiphenyl ether (3)，1,2,5- tribromo-3-bromoamino-7-bromomethylnaphthalene (4)，2,5,8-tribromo-3-bromo- amino-7-bromomethylnaphthalene (5)，2,5,6-tribromo-3-bromoamino-7-bromo- methylnaphthalene (6), 2,5,6,5',6'-pentabromo-3,4,3',4'-tetramethoxybenzophenone (7), (4E)-1-bromo-5-[(1'S*,3'R*)-3'-bromo-2',2'-dimethyl-6'-methylenecyclohexyl] -3-methylpent-4-ene-2,3-diol (8)，4-hydroxy-Palisadin C (9)，Isopalisol (10)，Luzonensol (11)，Palisadin B (12)，Aplysistatin (13)，Palisadin A (14)，5-Acetoxypalisadin B (15)，Aristolan-1(10)- en-9-ol (16)，Aristol-8-en-1-one (17)，Aristolan-9-en-1-one (18)，Aristolan-1(10)-en- 9-one (19)，Aristofone (20)，Aristolan-1(10)-8-diene (21)，Aristolan-1,9-diene (22)，10-Hydroxyaristolan-9-one (23)，7,11,15-trimethyl-3-methylene-hexadecan-1,2-diol (24)，3β-Hydroxyergosta- 5,24(28)-dien-7-one (25)，Isofucosterol (26)，β-sitosterol (27)，豆甾-4-烯-3α,6β-二醇 (28)，Cholesta-5-en-3β-ol (29)，Stigmasterol (30)，2,3,5,6-四溴-吲哚 (31)，2,3,6-tribromo-1H-indole (32)，3,5,6-tribromo-1-methylindole (33)，3,5,6-tribromo -1H-indole (34)，2,3,5-tribromo-1-methylindole (35)，其中化合物1-9为新化合物，化合物10-15、20和化合物24-30均为首次从该种海藻中得到。对新化合物1-9进行PTP1B酶抑制剂活性筛选，新化合物1、3、7显示强的PTP1B酶抑制活性。 对红藻齐藤凹顶藻Laurencia saitoi乙酸乙酯萃取物进行分离纯化，从中得到单体化合物11个，通过波谱学方法（IR、MS、NMR等）鉴定了他们的结构，分别为：2-hydroxyl-Luzofuranone (1)，2-hydroxyl-Luzofuranone B (2)，4-hydroxyl-Palisudin C (3)，2-bromo-γ-ionone (4)，Aplysistatin (5)，5-Acetoxypalisadin B (6)，Palisadin B (7)，Palisadin A (8)，Pacifigorgiol (9)，豆甾-4-烯-3α,6β-二醇 (10)，2, 3, 5, 6-四溴-吲哚 (11)，其中化合物1-4为新化合物，所有化合物均为首次从该种海藻中得到。通过MTT法对分离得到的新化合物1-4进行肿瘤细胞毒活性筛选，结果显示4个新化合物对所测肿瘤细胞株均无明显的活性。 对红藻瘤状软骨凹顶藻Chondrophycus papillous乙酸乙酯萃取物进行分离纯化，从中得到单体化合物5个，通过波谱学方法（MS、NMR等）鉴定了他们的结构，分别为邻苯二甲酸二丁酯 (1)，邻苯二甲酸二异辛酯 (2)，胆甾醇 (3)，3,7,11,15-tetramethyl-hexadec-2-en-1-ol (4)，4-羟基苯甲醛 (5)，所有化合物均为首次从该种海藻中得到。 对海洋放线菌M159乙酸乙酯萃取物进行分离纯化，从中得到单体化合物13个，通过波谱学方法（MS、NMR等）鉴定了他们的结构，分别为：5-(4',6'-dihydroxy-6-methyloctyl)furan-2(5H)-one (A)，phenethyl alcohol (1)，4-羟基苯甲醛(2)，anthranilic acid (3)，4-Hydroxy-3-methoxy- phenyl-propionic acid (4)，5-(6,7-dihydroxy-6-methyloctyl)furan-2(5H)-one (5)，p-Hydroxyphenylethyl alcohol (6)，3-Indoleacrylic acid (7)，Indol-3-carboxylic acid (8)，Adenine cordyceposide (9)，腺嘌呤核苷(10)，尿嘧啶核苷(11)，Thymidine (12)，其中化合物A为新化合物。所有化合物均为首次从该株放线菌中得到。 对海洋放线菌L211乙酸乙酯萃取物进行分离纯化，从中得到单体化合物15个，通过波谱学方法（MS、NMR等）鉴定了7个结构，分别为：spatozoate (1)，anthranilic acid (2)，3-Indolylethanol (3)，1-Acetyl-β-carbolin (4)，p-Hydroxyphen- ylethyl alcohol (5)，Indole-3-acetic acid (6)，Indol-3-carboxylic acid (7)，所有化合物均为首次从该株放线菌中得到。

Minor sesquiterpenes with new carbon skeletons from the brown alga Dictyopteris divaricata

Five minor sesquiterpenes (1-5) with two novel carbon skeletons, together with a minor new oplopane sesquiterpene ( 6), have been isolated from the brown alga Dictyopteris divaricata. By means of spectroscopic data including IR, HRMS, 1D and 2D NMR, and CD, their structures including absolute configurations were assigned as (+)-(1R, 5S, 6S, 9R)3- acetyl-1-hydroxy-6-isopropyl-9-methylbicyclo[4.3.0] non-3-ene ( 1), (+)-(1R, 3S, 4S, 5R, 6S, 9R)-3-acetyl-1,4-dihydroxy-6- isopropyl-9-methylbicyclo[4.3.0] nonane (2), (+)-(1R, 3R, 4R, 5R, 6S, 9R)-3-acetyl-1,4-dihydroxy-6-isopropyl-9-methylbicyclo[ ;4.3.0] nonane ( 3), (+)-(1S, 2R, 6S, 9R)-1-hydroxy-2-(1-hydroxyethyl)-6-isopropyl-9-methylbicyclo[4.3.0] non-4-en-3-one (4), (-)-( 5S, 6R, 9S)-2-acetyl-5-hydroxy-6-isopropyl-9-methylbicyclo[4.3.0] non-1-en-3-one ( 5), and (-)-( 1S, 6S, 9R)- 4-acetyl- 1-hydroxy-6-isopropyl-9-methylbicyclo[ 4.3.0] non-4-en-3-one ( 6). Biogenetically, the carbon skeletons of 1-6 may be derived from the co-occurring cadinane skeleton by different ring contraction rearrangements. Compounds 1-6 were inactive (IC50 > 10 mu g/mL) against several human cancer cell lines.