Synthesis of cyclic thioethers through tandem C(sp3)-S and C(sp2)-S bond formations from alpha,beta'-dichloro vinyl ketones

The synthesis of 5- to 8-memebered cyclic thioethers 4 has been achieved through a simple two-step sequence. The present methodology utilizes the facile Friedel-Crafts acylation of terminal alkynes 1 with acid chlorides 2 followed by tandem C(sp(3))-S and C(sp(2))-S bond formations with NaSH.xH(2)O.     

Green Synthesis of Silver Nanoparticles Using Arachis hypogaea (Ground Nut) Root Extract for Antibacterial and Clinical Applications

The present study focused on the green synthesis of silver nanoparticles (AgNPs) using Arachis hypogaea (ground nut) root extract for the antibacterial and clinical application. The presence of major phytochemical compounds are found to be 2H-Pyaran,2,5-diethenyltetrahydro, Didodecyl phthalate, Decanoic acid, Tetradecanoic acid, Bis(2-ethylhexyl) phthalate, Dodecanoic acid, Phosphonic acid, 2-(4-Methoxyphenyl)-5-(4-methoxynaphthyl) thiophene and Methyl 2-(N-Benzylimino)-4-chloro-3,3-dimethylbutanoate by GC–MS. Nanoparticles synthesis is confirmed by UV–Vis analysis by observing the maximum absorption spectrum at 450 nm. XRD and SEM–EDX results reveals the synthesized nanoparticles are cubic crystalline with agglomerated particles of silver oxide with biomolecules present around it. TEM images clearly shows that the biosynthesized nanoparticles are mostly spherical and irregular shaped with an average particles size of 30 nm. Highest susceptibility pattern of silver nanoparticle against Enterococcus sp. (35 ± 0.4 mm) which followed by Pseudomonas sp. (33 mm) and Staphylococcus aureus (29 mm). Green synthesized nanoparticles are coated over the commercially available clinical band aid cloth by dip coating method. Silver nanoparticle incorporated band aid cloth showed good antibacterial activity against the harmful bacteria which usually cause infection and interfere during wound healing. Our findings revealed that green nanoparticle has a good antibacterial action against harmful bacteria and showed good response for efficient clinical application.     

Four new aromatic allenic ethers from the fungus Xylaria sp. No. 2508

Four new aromatic allenic ethers, (7E)-3-(4-buta-2,3-dienyloxy-3-methoxy-phenyl)-acrylic acid methyl ester (1), (7E)-3-[4-(4-buta-2,3-dienyloxy-benzyloxy)-phenyl]-acrylic acid methyl ester (2), 4-(4-buta-2,3-dienyloxy-benzyloxy)-benzoic acid methyl ester (3), (7E)-3-[4-(4-buta-2,3- dienyloxy-benzyloxy)-3-methoxy-phenyl]-acrylic acid methyl ester (4) were isolated from the fungus Xylaria sp. No. 2508. The structures of those compounds were determined by analysis of spectroscopic data, mainly 2D NMR experiments.     

Biosynthetic origins of C-P bond containing tripeptide K-26

[reaction: see text] Primary metabolic precursors for K-26, a naturally occurring tripeptide phosphonic acid from Actinomyces sp. K-26, are investigated by heavy-atom isotope labeled substrate incorporation experiments. A highly sensitive selected reaction monitoring (SRM)-based method for isotopic incorporation estimation in natural products is reported. The incorporation of heavy-atom isotope labeled tyrosine compounds into the (R)-1-amino-2-(4-hydroxyphenyl)-ethylphosphonic acid moiety of compound K-26 suggests a new mechanism of biosynthesis of phosphonate functionality in natural products.     

Asymmetric synthesis of nonproteinogenic amino acids with l-amino acid transaminase: synthesis of (2S)-2-amino-4-oxo-4-phenylbutyric and (3E,2S)-2-amino-4-phenylbutenoic acids

2,4-Dioxo-4-phenylbutyric acid and 2-oxo-4-phenylbut-3-enoic acid are converted to the corresponding (S)-2-amino acids by recombinant Escherichia coli whole cells over-expressing aromatic transaminase from Enterobacter sp. BK2K-1 (AroATEs) in high yields (68–78%) and high enantiomeric purity (>99%) using l-aspartic acid as an amino donor.     

红树林真菌Penicillium sp．No．ZZF33发酵液化学成分的研究

海洋微生物是寻找药物先导化合物的一个新的源泉,人类已从海洋微生物的次级代谢产物中发现了许多有生物活性的结构新颖的化合物[1]。近几年,本研究组对来自南中国海红树林的海洋真菌的代谢产物进行了系统的研究,从中发现大量有生物活性的化合物,揭示了红树林真菌的巨大应用潜力     

Largamides A-H, unusual cyclic peptides from the marine cyanobacterium Oscillatoria sp

Seven new depsipeptides, termed largamides A-G (1-7), and one new cyclic peptide, largamide H (8), have been isolated from the marine cyanobacterium Oscillatoria sp. Their structures were determined by NMR and ESI-MS techniques. The absolute configurations were assigned using LC-MS, chiral HPLC, and combined analysis of homonuclear and heteronuclear (2,3)J couplings, along with ROE data. Largamides, isolated from a single homogeneous cyanobacterial collection, represent three different structural classes of peptides. Largamides A-C (1-3) are characterized by the unusual occurrence of a senecioic acid unit, while largamides B (2) and C (3) possess in addition the rare 2-amino-5-(4'-hydroxyphenyl)pentanoic acid (Ahppa) and the novel 2-amino-6-(4'-hydroxyphenyl)hexanoic acid (Ahpha), respectively. Largamides D-G (4-7) are the first 3-amino-6-hydroxy-2-piperidone acid (Ahp)-containing depsipeptides reported with the rare Ahppa unit. Largamide H (8) is a unique cyclic peptide displaying a new 2,5-dihydroxylated beta-amino acid moiety, a methoxylated derivative of Ahppa, and two residues of the nonstandard 2,3-dehydro-2-aminobutanoic acid (Dab). Largamides D-G (4-7) inhibited chymotrypsin with IC(50) values ranging between 4 and 25 microM.     

Synthesis of seco-chlorinated derivatives of phenanthroindolizidine precursors via Friedel-Crafts reaction

In the course of synthesizing 3-demethyltylophorine (1) by Lewis acid catalyzed intramolecular Friedel-Crafts reaction starting from N-(3-hydroxy-2,6,7-trimethoxy-phenanthr-9-ylmethyl)-2-chloromethylpyrrolidine, two chlorinated phenanthrene derivatives N-(4,10-dichloro-3-hydroxy-2,6,7-trimethoxyphenanthr-9-ylmethyl)-2-chloromethylpyrrolidine (4) and N-(4-chloro-3-hydroxy-2,6,7-trimethoxyphenanthr-9-ylmethyl)-2-chloromethylpyrrolidine (5) were obtained. The structures of these compounds were determined by spectroscopic analysis.     

Seimatoric acid and colletonoic acid:Two new compounds from the endophytic fungi,Seimatosporium sp.and Colletotrichum sp.

A new metabolite,named seimatoric acid(1),representing a new oxobutanoic acid derivative has been isolated from Seimatosporium sp., in addition to four known compounds viz.,2-hydroxymethyl-4β,5α,6β-trihydroxycyclohex-2-enone(2),(-)-phyllostine(3),(+)-epiepoxydon(4) and(+)-epoxydon monoacetate(5).Similarly one new benzoic acid derivative,named colletonoic acid(6) was isolated from the ethyl acetate fraction of Colletotrichum sp.The structures of the new compounds were elucidated by detailed ~1 H NMR,~(13)C NMR,COSY,HMQC.HMBC spectroscopic analysis,and HR-E1-MS.Seimatoric acid(1)was also isolated from another taxonomical unidentified fungal strain 4295 in ourgroup.The structures of the known compounds were elucidated by their spectral data comparison to literature data.Preliminary studies showed that colletonoic acid(6) showed good antibacterial,antifungal,and antialgal activities.     

Homophymine A, an anti-HIV cyclodepsipeptide from the sponge Homophymia sp

A new anti-HIV cyclodepsipeptide, homophymine A, was isolated from a New Caledonian collection of the marine sponge Homophymia sp. The structure of homophymine A was determined by interpretation of spectroscopic data, acid hydrolysis, and LC-MS analysis. Homophymine A contains 11 amino acid residues and an amide-linked 3-hydroxy-2,4,6-trimethyloctanoic acid moiety. Along with four D-, two L-, and one N-methyl amino acids, it also contains four unusual amino acid residues: (2S,3S,4R)-3,4-diMe-Gln, (2R,3R,4S)-4-amino-2,3-dihydroxy-1,7-heptandioic acid, L-ThrOMe, and (2R,3R,4R)-2-amino-3-hydroxy-4,5-dimethylhexanoic acid. In a cell-based XTT assay, homophymine A exhibited cytoprotective activity against HIV-1 infection with a IC50 of 75 nM.     

酸对脱乙酰甲壳质稀溶液粘度的影响

脱乙酰甲壳质是甲壳质衍生物中最重要,用途最为广泛的一种,属阳离子性聚电解质,可以溶于多种稀酸溶液中,本文从脱乙酰甲壳质在甲酸、乙酸和丁酸溶液中的粘度变化,研究其稀溶液性质。分別考察了脱乙酰甲壳质在8×10~(71)～3×10~(72)/1,酸浓度在5×10~(-1)～1×10~(-1)mol范围内溶液ηsp/c-c的关系。实验结果表明,作为脱乙酰甲壳质溶剂的酸,在溶液稀释时对溶液ηsp/c的影响,在不同的阶段可以是完全不同的。当溶液中可离解的酸还未能完全满足游离氨基成盐要求时,酸溶液的增加将导致溶液的ηsp/c的增加,而一旦游离氨都已成盐,过量酸的增加都会导致溶液粘度的下降。而在一般情况下,酸的酸性越强,酸的浓度越大,都会使溶液得到较低的粘度值。     

Structure and chemistry of apicidins, a class of novel cyclic tetrapeptides without a terminal alpha-keto epoxide as inhibitors of histone deacetylase with potent antiprotozoal activities

Apicidins are a class of cyclic tetrapeptides that do not contain the classical electrophilic alpha-keto epoxide yet are potent (nM) inhibitors of histone deacetylase and antiprotozoal agents. These compounds showed broad-spectrum activities against the apicomplexan family of protozoa including Plasmodium sp (malarial parasite), Toxoplasma gondii, Cryptosporidium sp., and Eimeria sp. These cyclic peptides contain a beta-turn amino acid (R)-Pip or (R)-Pro, (S)-N-methoxy Trp, (S)-Ile, or (S)-Val, and either (S)-2-amino-8-oxodecanoic acid or a modified (S)-2-amino-8-oxodecanoic acid. The isolation and structure elucidation of new apicidins from two Fusarium species, temperature-dependent NMR studies of apicidin, NMR and molecular modeling based conformation of the 12-membered macrocyclic ring, and selected chemical modifications of apicidin have been detailed in this paper. The cyclic nature of the peptide, the C-8 keto group, and the tryptophan are all critical for the biological activity.     

海洋放线菌Streptomyces sp. 124092中的细胞毒活性成分

对海洋放线菌Streptomyces sp.发酵液的提取物进行柱层析分离, 得到5个化合物. 经MS, NMR, 1H-1H COSY, HSQC和HMBC等数据鉴定, 其结构分别为3-氨基-丙酸对甲苯酯(1)、6-Amino-3-(4-hydroxybenzyl)-1,4-diazonane-2,5-dione(2)、正丁基-α-D-吡喃甘露糖苷(3)、大豆苷元(4)和1H-3-吲哚甲酸(5). 其中化合物1和2为新化合物, 细胞毒活性测试结果表明, 化合物1~4对人肝癌细胞(SMMC-7721)具有不同程度的生长抑制活性.     

Determination of the uronic acid composition of seaweed dietary fibre by HPLC

A high-performance liquid chromatographic (HPLC) method is described for determination of the ratio of beta-d-mannuronic acid to alpha-l-guluronic acid (M/G ratio) in dietary fibre of edible seaweeds. Total dietary fibre (TDF) content was determined gravimetrically. The TDF fraction was hydrolysed with 12 m and 1 m H(2)SO(4), then neutralized with AG 4 x 4 resin. The uronic acids were separated in a Tracer Extrasil SAX 5 micro m column (25 cm x 4 mm) at 35 degrees C, with 2 mm KH(2)PO(4) containing 5% methanol as mobile phase at a fl ow rate of 1.5 mL/min. The detection wavelength was UV 210 nm. The chromatographic identifications of beta-d-mannuronic acid and alpha-l-guluronic acid were confirmed by liquid chromatography-mass spectrometry (LC-MS). The method precision was 1.4% for beta-d-mannuronic acid and 3.5% for alpha-l-guluronic acid. The method was used to determine M/G ratio in canned seaweeds (Saccorhiza polyschides and Himanthalia elongata) and in dried seaweeds (H. elongata, Laminaria ochroleuca, Undaria pinnatifida, Palmaria sp. and Porphyra sp.).     

Metabolic Products of Microorganisms. Part 269. 5-Phenylpentadienoic-acid derivatives from Streptomyces sp.

Two new phenylpentadienamides isolated from the culture filtrate of Streptomyces sp. were assigned the structures 5-(4-aminophenyl)penta-2,4-dienamide ( 2 ) and N²-[5-(4-aminophenyl)penta-2,4-dienoyl]-L -glutamine ( 3 ). In addition, 5-(4-aminophenyl)penta-2,4-dienoic acid ( 1 ) has been isolated, and its spectroscopic characteristics are reported for the first time. Compounds 1–3 exist in both the (2E,4E)- and (2E,4Z)-configurations. Electrospray and tandem MS, and HPLC/MS proved to be particularly suitable for the characterization of these metabolites.     

Arthrobacter sp.: a lipase of choice for the kinetic resolution of racemic arylazetidinone precursors of taxanoid side chains

The native strain of Arthrobacter sp. (MTCC 5125) bearing a lipase has been found to be the most effective in the kinetic resolution of racemic arylazetidinones for producing cis-(3R,4S)-3-acetoxy-1-(4-methoxyphenyl)-4-phenyl-2-azetidinone, cis-(3R,4S)-3-acetoxy-1-(4-methoxyphenyl)-4-(2-furanyl)-2-azetidinone, cis-(3R,4S)-3-acetoxy-1-(4-methoxyphenyl)-4-(2-thienyl)-2-azetidinone, and cis-3-acetoxy-4-(t-butyl)-2-azetidinone products. The resolved compounds, which were obtained in high enantiopurity are important intermediates of amino acid side chains of paclitaxel as well as a new generation of taxanoids. The use of co-solvents dramatically improved the resolution efficacy of the lipase.     

Synthesis,Structure, and Biological Activity of Products of Reactions of 3,4-Dioxohexane-1,6-dioic Acid Esters with 2-Aminophenol

Bioactive derivatives of 1,4-benzoxazine have been prepared via reactions of 3,4-dioxohexane-1,6- dioic (ketipic) acid esters with 2-aminophenol. (2'Z)-2,2'-(2-Hydroxy-2H-1,4-benzoxazin-2-yl-3-ilidene)diacetic acid esters or (2Z)-[2-oxo-2H-1,4-benzoxazin-3(4H)-ylidene]acetic acid esters can be formed depending on the conditions. The structures of the products of dialkyl ketipate esters reactions with 2-aminophenol were determined by means of X-ray diffraction. It has been demonstrated that the prepared compounds exhibit antimycotic activity against test cultures of plant pathogenic fungi (Fusauium sp., Alternarium sp., and Bipolaris soraciniana).     

培养南海红树林内源真菌Fusarium sp. ZZF60产新型蒽醌衍生物

通过人工发酵培养,从南海红树林内源真菌Fusarium sp.ZZF60的培养液中分离得到:1种新蒽醌衍生物,6,8-二甲氧基-1-甲基-2-(3-氧丁基)蒽醌(1),以及5种已知化合物:7-羟基-3-(4-甲氧基苯基)苯并-γ-吡喃酮(2),2,4-二羟基-6-[(1′E,3′E)-1′,3′-戊二烯基]苯甲醛(3),(E)-4-羟基肉桂酸甲酯(4),4-(4-羟基苯基)-2-丁醇(5),4-羟基苯甲酸(6)。它们的结构通过MS、NMR等波谱分析推导确定。初步药理活性显示,化合物1抑制体外培养人喉癌细胞Hep2和人肝癌细胞HepG2的IC50分别为16和23μmol/L。     

R 和 s-1-(3'-溴-4'-甲氧基)苄基-2-甲基-6-甲氧基-7-羟基-1, 2,3,4-四氢异喹啉的合成

本文报道了R和S-1-(3'-溴-4'-甲氧基)苄基-2-甲基-6-甲氧基-7-羟基-1,2,3,4-四氢异喹啉的合成。