Synthesis of phthalide derivatives using nickel-catalyzed cyclization of o-haloesters with aldehydes

The reaction of o-bromobenzoate (1 b) with benzaldehyde (2 a) in the presence of [NiBr(2)(dppe)] (dppe=1,2-bis(diphenylphosphino)ethane) and zinc powder in THF (24 hours, reflux temperature), afforded 3-phenyl-3H-isobenzofuran-1-one (3 a) in an 86 % yield. Similarly, o-iodobenzoate reacts with 2 a to give 3 a, but in a lower yield (50 %). A series of substituted aromatic and aliphatic aldehydes (2 b, 4-MeC(6)H(4)CHO; 2 c, 4-MeOC(6)H(4)CHO; 2 d, 3-MeOC(6)H(4)CHO; 2 e, 2-MeOC(6)H(4)CHO; 2 f, 4-CNC(6)H(4)CHO; 2 g, 4-(Me)(3)CC(6)H(4)CHO; 2 h, 4-C(6)H(5)C(6)H(4)CHO; 2 i, 4-ClC(6)H(4)CHO; 2 j, 4-CF(3)C(6)H(4)CHO; 2 k, CH(3)(CH(2))(5)CHO; 2 l, CH(3)(CH(2))(2)CHO) also underwent cyclization with o-bromobenzoate (1 b) producing the corresponding phthalide derivatives in moderate to excellent yields and with high chemoselectivity. Like 1 b, methyl 2-bromo-4,5-dimethoxybenzoate (1 c) reacts with tolualdehyde (2 b) to give the corresponding substituted phthalide 3 m in a 71 % yield. The methodology can be further applied to the synthesis of six-membered lactones. The reaction of methyl 2-(2-bromophenyl)acetate (1 d) with benzaldehyde under similar reaction conditions afforded six-membered lactone 3 o in a 68 % yield. A possible catalytic mechanism for this cyclization is also proposed.     

液-液萃取电感耦合等离子体质谱法测定天然水中痕量稀土元素

建立了以单、二（2－乙基己基）磷酸酯混合螯合剂的庚烷溶液作为萃取剂，6.0mol/L HCl反萃取预分离富集，In和Rh做内,ICP-MS测定天然水中15种稀土元素的分析方法。方法的富集倍数为200倍，各元素的检出限范围在0.01-1.8ng/L之间，相对标准偏差RSD＜5％，萃取回收率＞93％。     

基于天然氨基酸的双环手性季铵盐相转移催化剂的合成及催化性能研究

以L－脯氨酸及L－羟基脯氨酸为原料合成了4个新型手性季铵盐磁相转移催化 剂，并用于催化不对称查耳酮环氧化反应，高产率得到相应环氧化合物，ee最高达 9％。     

Steam-carbon gasification catalyzed by calcium: Assessment of the porous structure of active carbons from plum stones and synthetic active carbons

A need for an elaboration of the methods for synthesis and characterization of activated carbons with a requisite porous structure has existed for a long time. One of the methods giving possibility for creating controlled mesopore and micropore structures deals with the steam gasification of various carbon materials. In this work the effects of calcium catalyst on the catalytic steam gasification of active carbons from plum stones and porous polymers are presented. Determination of micropores capacity and specific adsorption in mesopores have been performed by means of the _s method, but adsorption on the heterogeneous solids was described by the integral equation with various local isotherms. This equation has been solved by the regularization method. Based on this method the changes in structural parameters of active carbons depending on the amount of calcium catalyst were estimated.Nomenclature d width of slit-like micropore - F(x) distribution function of the half-width - p vapor pressure of sorbate - p/p _N relative pressure - PSAC Plum Stone Active Carbon - average pore radius, nm - S ₁ relative limit of the validity of experimental point on the adsorption isotherm in the computations by means of regularization method - SAC Synthetic Active Carbon - S _BET specific surface area calculated by means of BET method, m²/g - S _mes mesopore surface area, m²/g - S _mic micropore surface area, m²/g - T absolute temperature, K - V _mes sorption capacity of mesopores, cm³/g - V _mic sorption capacity of micropores, cm³/g - V _p sorption capacity of pores, cm³/g - w/w weight in weight concentration - x half-width of slit-like micropore, nm - x ₁ maximum of half-width of micropore slit, nm - average half-width of slit-like micropore, nm - X _min-X _max integration limits of thex Greek Letters Greek Letters variance of average half-width of slit-like micropore, nm² - local relative filling of micropores - total relative filling of micropores     

Ring‐Rearrangement Metathesis

Ring‐rearrangement metathesis (RRM) refers to the combination of several metathesis transformations into a domino process, in which an endocyclic double bond of a cycloolefin reacts with an exocyclic alkene. RRM has proven to be a powerful method for the rapid construction of complex structures. The extension of the basic ring‐opening–ring‐closing metathesis process by further metathesis steps as well as an examination of the driving forces, limits, scope, recent advantages, and future perspectives of these domino sequences is presented with various examples, thus reflecting the high efficiency and utility of RRM in organic synthesis.     

Antimicrobial properties of natural substances in irradiated fresh poultry

This study was undertaken to determine if a combined treatment (marinating in natural plant extracts or vacuum) with irradiation could have a synergetic effect, in order to reduce the dose required for complete elimination of Salmonella on fresh poultry. The effect of these combined treatments on the shelf-life extension was also evaluated. The fresh chicken legs were irradiated at 0, 3 and 5 kGy. The poultry underwent microbial analysis(mesophilic and Salmonella detection). For each treatment, the total microbial count decreased with increase of irradiation dose. The marinating treatment have a synergistic effect with irradiation treatment to reduce the total microbial count and controlling the proliferation during storage at 4°C. Irradiation of fresh chicken pieces with a dose of 3 kGy appears to be able to extend the microbial shelf-life by a factor of 2. When the chicken is marinating and irradiated at 3 kGy or when irradiated at 5 kGy without marinating, the microbial shelf-life is extended by a factor of 7 to 8. No Salmonella was found during all the experiment in the chicken in air and marinated. However, a presence of Salmonella was found in samples irradiated at 5 kGy under vacuum, in unirradiated samples and samples irradiated at 3kGy in air and under vacuum.     

微波萃取花生壳天然黄色素及其稳定性研究

对福建产花生壳进行了微波萃取天然黄色素及其稳定性的研究 .研究表明微波萃取的工艺条件是 :以pH =3,体积分数 70 %的乙醇水溶液作提取剂 ,原料与提取剂配比为 1g∶5mL ,微波辐射功率为 12 0W ,辐射时间2 4 0s.对该色素稳定性研究结果表明 ,该色素为水溶性色素 ,属黄酮类色素 ,适用pH值范围比较宽 ,尤其碱性状态效果最佳 ,对光、热稳定性好 ,大多数食品添加剂对色素稳定性影响不大 ,对氧化剂H2 O2 的耐受能力较差 ,对还原剂Na2 SO3 的耐受能力强     

First chemical study of anaspidean Syphonota geographica: structure of degraded sterols aplykurodinone-1 and -2

Two unprecedented degraded sterols, aplykurodinone-1 (1) and -2 (2), have been isolated from the skin of the marine anaspidean Syphonota geographica, collected along the coasts of Greece. The structures and the relative stereochemistry were established by spectroscopic analysis and confirmed by chemical correlation with related known compounds.     

The polysaccharide extracts from the fungi Coprinus comatus and Coprinellus truncorum do exhibit AChE inhibitory activity

The polysaccharide (PSH) extracts from the edible mushroom species Coprinus comatus and Coprinellus truncorum were screened in liquid for their acetylcholinesterase inhibitory (AChE) activity. Both extracts were found to display inhibition of the aforementioned enzyme reaching similar IC₅₀ values of 0.62 ± 0.07 and 0.61 ± 0.03 mg/mL, respectively. According to the means of FTIR spectroscopy, these PSH extracts mostly contained β-glucans. However, the presence of some proteins and polyphenolics as minor ingredients were also detected. Compared with existing literature data for anti-AChE activity of the sugar samples, the findings within this study may be treated as a profound bioactivity. Consequently, this study puts some light on the possible use of the screened macrofungi in the palliative treatment of Alzheimer’s disease.     

Stereoselective synthesis of the cyclic ether core of (+)-laurenyne

A concise enantioselective synthesis of the cyclic ether core of the marine natural product (+)-laurenyne has been accomplished using ring-closing metathesis for medium-ring construction.