Synthesis of cyclic diacetals of fumaraldehyde, α, α'-dibromosuccinaldehyde,and but-2-ynedial

A number of cyclic diacetals of but-2-ynedial, fumaraldehyde, andα, α'-dibromosuccinaldehyde have been synthesized by the transacetalation of bis(dimethyl acetal)s of 1,2- and 1,3-glycols. The succinaldehyde derivatives have also been obtained by the bromination of the corresponding diacetals of fumaraldehyde.     

Organocatalyzed Michael-Henry reactions: enantioselective synthesis of cyclopentanecarbaldehydes via the dienamine organocatalysis of a succinaldehyde surrogate

Asymmetric formal [3+2] cycloadditions of 4-hydroxybut-2-enal, a succinaldehyde surrogate, and nitroalkenes with an organocatalyst provided cyclopentanecarbaldehydes containing four consecutive stereogenic centers with excellent enantioselectivities.     

La reaction de Wittig-Horner en milieu heterogene IX. Bis aldolisation des phosphonates a partir des dialdehydes aliphatiques en milieu aqueux peu basique. Synthese de cyclenols fonctionnels.

Aqueous solutions of glutaraldehyde and succinaldehyde give respectively improved yields of 1-functional 6-cyclohexenols and 5-cyclopentenols, when subjected to WITTIG-HORNER reaction in water at room temperature, with potassium carbonate as a base.     

An organocatalytic direct Mannich-cyclization cascade as [3+2] annulation: asymmetric synthesis of 2,3-substituted pyrrolidines

A new method for asymmetric synthesis of 2,3-substituted pyrrolidines from N-PMP aldimines and succinaldehyde via formal [3+2] cycloaddition is reported. This reaction involves proline catalyzed direct Mannich reaction and acid catalyzed reductive cyclization with high yields (up to 78%) and excellent enantioselectivities (up to >99%).     

Alkylation d'acetates de cyclenols fonctionnels (5 et 6 chainons) par les reactifs de grignard et les enolates lithiens catalysee (ou non) par les sels de cuivre (I). Synthese rapide de la (±) mitsugashiwalactone

Substitution of 1-ethoxycarbonyl n-hydroxycycloalkenes acetates and silyl ethers (n = 5, 6) by GRIGNARD reagents in the presence of cuprous salt as a catalyst or lithium ester enolates (without catalyst) gives rise to various 1-carbethoxy alkylcycloalkenes. It is applied to a new short stereoselective synthesis of (±) Mitsugashiwalactone (6 steps - 27 % global yield) from a succinaldehyde precursor.     

去甲氯胺酮半抗原及其全抗原的合成与鉴定

在低温条件下,去甲氯胺酮与琥珀醛酸反应,合成了半抗原羧基-去甲氯胺酮,电喷雾质谱鉴定结果表明,目标半抗原合成成功;通过碳二亚胺法将半抗原与载体蛋白偶联制备人工抗原,红外光谱法鉴定结果表明,人工抗原合成成功,基质辅助激光解析电离飞行时间质谱鉴定表明去甲氯胺酮半抗原与牛血清白蛋白的偶联比为11:1。经动物免疫,获得高效价特异性多克隆抗体,抗血清效价可达5.12×104。     

Prostaglandin Total Synthesis Enabled by the Organocatalytic Dimerization of Succinaldehyde

Prostaglandins have been attractive targets in total synthesis for over 50 years, resulting in the development of new synthetic strategies and methodologies that have served the broader chemical community. However, these molecules are not just of academic interest, a number of prostaglandin analogues are used in the clinic, and some are even on the WHO list of essential medicines. In this personal account, we describe our own approach to the family of prostaglandins, which centers around the synthesis of a key enal intermediate, formed from the l ‐proline catalysed dimerization of succinaldehyde. We highlight the discovery and further optimization of this key reaction, its scale up, and subsequent application to a range of prostaglandins.     

THE U.V. PHOTOLYSIS (Λ= 185nm) OF ETHYLENE GLYCOL IN AQUEOUS SOLUTION*

Abstract— –The u.v. photolysis (Λ= 185 nm) of 2 M aqueous solutions of ethylene glycol was studied at 22°C. Products (quantum yields) are hydrogen (0.20₄) formaldehyde (0.19₄), glycolaldehyde (0.08), methanol (0.07₄), glycerol (0.06), erythritol (0.03), acetaldehyde (0.02), 3,4-dihydroxybutanal (0.01) and succinaldehyde (0.001). With increasing temperature the yields of all products remain essentially unchanged except that of acetaldehyde (φ= 0.32 at 90°C) which is formed in a chain reaction. The photolysis of (CD₂OH)₂ yields 91% HD, indicating that the most important primary process is the homolytic splitting of the O-H bond. The resulting oxy radicals fragmentate largely into formaldehyde and CH₂OH radicals. Molecular fragmentation processes yielding hydrogen and glycolaldehyde, as well as formaldehyde and methanol, are discussed in the proposed decomposition scheme.     

The Tannins from Sanguisorba officinalis L. (Rosaceae): A Systematic Study on the Metabolites of Rats Based on HPLC–LTQ–Orbitrap MS2 Analysis

Sanguisorba tannins are the major active ingredients in Sanguisorba ofJicinalis L. (Rosaceae), one of the most popular herbal medicines in China, is widely prescribed for hemostasis. In this study, three kinds of tannins extract from Sanguisorba officinalis L. (Rosaceae), and the metabolites in vivo and in vitro were detected and identified by high-pressure liquid chromatography, coupled with linear ion trap orbitrap tandem mass spectrometry (HPLC–LTQ–Orbitrap). For in vivo assessment, the rats were administered at a single dose of 150 mg/kg, after which 12 metabolites were found in urine, 6 metabolites were found in feces, and 8 metabolites were found in bile, while metabolites were barely found in plasma and tissues. For in vitro assessment, 100 μM Sanguisorba tannins were incubated with rat liver microsomes, liver cytosol, and feces, after which nine metabolites were found in intestinal microbiota and five metabolites were found in liver microsomes and liver cytosol. Moreover, the metabolic pathways of Sanguisorba tannins were proposed, which shed light on their mechanism.     

Magnetic solid-phase extraction of warfarin and gemfibrozil in biological samples using polydopamine-coated magnetic nanoparticles via core-shell nanostructure

Herein, polydopamine-coated Fe₃O₄ spheres were synthesized using a very simple, easy, cost-effective, efficient, and fast method. First, magnetic nanoparticles (Fe₃O₄) were synthesized and were followed by accommodating polydopamine on the surface of the prepared Fe₃O₄. The prepared polydopamine-coated Fe₃O₄ spheres were utilized as a sorbent in magnetic solid phase extraction of gemfibrozil and warfarin (as the model analytes). The extracted model analytes were desorbed by a suitable organic solvent and were analyzed by high-performance liquid chromatography. Under optimized condition, the linearity of the method was in the range of 0.1–200.0 μg/L for the selected analytes in water. The limits of detection were calculated to be in the range of 0.026–0.055 μg/L for warfarin and gemfibrozil, respectively. The limits of quantification were calculated to be in the range of 0.089–0.185 μg/L. The inter-day and intra-day relative standard deviations were determined to be in the range of 1.4%–3.3% in three concentrations in order to calculate the method precision. Furthermore, the enrichment factors were found to be 78 and 81 for warfarin and gemfibrozil, respectively. Moreover, the calculated absolute recoveries were between 78% and 81%. The obtained recoveries indicated that the method was useful and applicable in complicated real samples.     

Über s-Triazinium-Salze und Additionsverbindungen des s-Triazins

Several unknown salts of s-triazine were prepared by different methods and the IR spectra of most of these salts were assigned. When s-triazine was reacted with HCl or HBr, mixtures were obtained which consisted of s-triazinium-monohalogenides and products with higher contents of hydrohalogenides. When s-triazine was reacted with HJ, a product C₃H₃N₃ · 3 HJ was obtained. The IR spectra of this compound and of the corresponding compound with DJ were taken to interprete the structure. Addition compounds of s-triazine with several ansolvo-acids were produced in which one or two ansolvo-acid molecules were bound to one molecule of s-triazine. The IR spectra of some of said addition compounds were assigned. Moreover, an adduct of bromine and s-triazine, C₃H₃N₃ · Br₂, was prepared.     

A Gibbs sampling method to determine biomarkers for asthma

PurposeTo identify potential biomarkers and to uncover the mechanisms underlying asthma based on Gibbs sampling.MethodsThe molecular functions (MFs) with genes greater than 5 were determined using AnnotationMFGO of BAGS package, and the obtained MFs were then transformed to Markov chain (MC). Gibbs sampling was conducted to obtain a new MC. Meanwhile, the average probabilities of MFs were computed via MC Monte Carlo (MCMC) algorithm, followed by identification of differentially expressed MFs based on the probabilities of MF more than 0.6. Moreover, the differentially expressed genes (DEGs) and their correlated genes were screened and merged, called as co-expressed genes. Pathways enrichment analysis was implemented for the co-expressed genes.ResultsBased on the gene set more than 5, overall 396 MFs were determined. After Gibbs sampling, 5 differentially expressed MF were acquired according to alfa.pi > 0.6. Moreover, the genes in these 5 differentially expressed MF were merged, and 110 DEGs were identified. Subsequently, 338 co-expressed genes were gained. Based on the P value < 0.01, the co-expressed genes were significantly enriched in 6 pathways. Among these, ubiquitin mediated proteolysis contained the maximum numbers of 35 co-expressed genes, and cell cycle were enriched by the second largest number of 11 co-expressed genes, respectively.ConclusionsThe identified pathways such as ubiquitin mediated proteolysis and cell cycle might play important roles in the development of asthma and may be useful for developing the credible therapeutic approaches for diagnosis and treatment of asthma in future.     

基于中空纤维液相微萃取的麻黄碱和伪麻黄碱优势构象的确定及含量测定

利用中空纤维液相微萃取方法(HF-LPME)分析麻黄碱和伪麻黄碱在不同基质中的优势构象,阐明了麻黄碱和伪麻黄碱的萃取机理;结合高效液相色谱(HPLC)建立了微量麻黄碱和伪麻黄碱的分离测定方法。以聚偏氟乙烯中空纤维为有机溶剂载体,正己醇为萃取溶剂,麻黄碱和伪麻黄碱的NaOH(5 mol/L)溶液为样品相,0.01 mol/L H2SO4溶液为接收相,在1200 r/min转速下萃取35 min,收集萃取液直接进行HPLC分析。麻黄碱和伪麻黄碱在水溶液中的线性范围为5～100 μg/L,检出限分别为1.9 μg/L和1.2 μg/L,富集倍数分别为38和61倍,平均回收率分别为100.6%±1.2%和103.2%±3.5%;在鼠尿液中的线性范围为100～5×104 μg/L,检出限分别为30 μg/L和42 μg/L,富集倍数分别为20和17倍,平均回收率分别为108.4%±4.4%和106.1%±5.4%。研究表明该方法操作简单,选择性高,适用于微量麻黄碱的含量测定和分析。     

Methyl modified siloxane melting gels for hydrophobic films

Hybrid melting gels were prepared by a sol–gel process, starting with a mono-substituted siloxane and a di-substituted siloxane. Methyl-modified melting gels were prepared using (a) methyltriethoxysilane (MTES) with dimethyldiethoxysilane (DMDES) and (b) methyltrimethoxysilane (MTMS) together with dimethyldimethoxysilane (DMDMS). The gels with MTES–DMDES were prepared with concentrations between 50–50 and 75–25 mol%. The gels with MTMS–DMDMS were prepared with concentrations between 50–50 and 70–30 mol%. For both systems, the consolidation temperature, after which the melting gel no longer softens, increased with an increase in the amount of the mono-substituted siloxane, increasing from 135 to 160 °C for MTES–DMDES and increasing from 145 to 170 °C for MTMS–DMDMS. Coatings formed on mica substrates were about 1 mm thick, and showed no visible cracks. The surfaces of the coatings were profiled using micro-Raman spectroscopy, which revealed that methyl groups were concentrated at the surfaces of the films. All contact angles measured with water were greater than 90°.     

Synthesis and physicochemical properties of 9,10-phenanthrenequinone monoxime and its nitro derivatives

Phenanthrenequinone monoxime and its mono-, di-, and trinitro derivatives were synthesized. The acidity constants and their variation with the number and position of nitro groups were determined. The electronic and IR spectra of the nitro compounds were studied. The bands in the electronic spectra were assigned based on quantum-chemical calculations in the Pariser—Parr—Pople approximation. Correlations between the pK _a values and some calculated characteristics of the compounds under study were found. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1106–1110, June, 1999.     

PHOTOPOLYMERS: SYNTHESIS AND CHARACTERIZATION OF POLY(4-CINNA-MOYLPHENYL METHACRYLATE) WITH GLYCIDYL METHACRYLATE

Copolymers of 4-cinnmoylphenyl methacrylate (CPMA) with glycidyl methacrylate were synthesized in methyl ethyl ketone solution using benzoyl peroxide as initiator at 70 ± 1°C. They were characterized by UV, IR, ¹H-NMR, and ¹³C-NMR spectra. Their compositions were determined by ¹H-NMR technique. The monomer reactivity ratios were determined by the Fineman-Ross and Kelen-Tüdös methods. The molecular weights ([Mbar]_w and [Mbar]_n) of the polymers were determined by GPC technique. Thermogravimetric analysis of the copolymers were carried out in air. The T_g of the polymers were determined by differential scanning calorimetry. The photocrosslinking properties of the homo and copolymers were also discussed.     

Measurements of hard beta emitters by Cerenkov detector

Boron and lithium content in various glass fiber-optics, enamel, and lake sediments were determined by measurement of the Cerenkov-radiation of¹²b and⁸Li using the fast rabbit-system of the Atominstitute. The decay-curves were also measured using a dead time correction unit (LFC) and evaluated with respect to interferences of other short-lived nuclides. Simultaneously, γ-spectra of short-lived nuclides were measured with the LFC-system. Main interferences in Cerenkov-counting were observed from²⁸Al and¹⁶N. High count-rates were measured correctly with the LFC-system. The halflives of⁸Li and¹²B were determined as well as their detection limits in glass and lake-sediments.     

Calcium alginate gel as encapsulation matrix for coimmobilized enzyme systems

Encapsulation within calcium alginate gel capsules was used to produce acoimmobilized enzyme system. Glucose oxidase (GOD) and catalase (CAT) were chosen as model enzymes. The same values of V _max and K _mapp for the GOD encapsulated system and for the GOD-CAT coencapsulated system were calculated. When gel beads and capsules were compared, the same catalyst deactivation sequence for the two enzymes was observed. However, when capsules were employed as immobilization support, GOD efficiencies were higher than for the gel beads. These results were explained in terms of the structure of the capsules.     

C-14 and H-3 contents in the groundwater around radioactive repository site in Korea

The contents of H-3 and C-14 in groundwater and surface waters around low and medium-level atomic waste repository site in Korea were determined. The concentrations of C-14 were in the range 0.186–0.287 Bq/L. The H-3 concentration of the groundwaters and surface waters were <0.06–5.75 and 1.22–4.74 Bq/L. The average H-3 contents of west, north and south direction were 1.18 ± 0.12, 1.11 ± 0.78 and 2.85 ± 2.66. H-3 and C-14 concentrations in the south direction were relatively higher than west and north direction samples. The surface waters sampled from catchment were four times higher than average H-3 concentration in precipitation. The concentrations of H-3 and C-14 within 5 km area samples were much higher than other samples.     

Chemical characterization of selected metals by X-ray fluorescence method in particulate matter collected in the area of Krakow, Poland

This study presents the results of year long (2007–2008) particulate matter collecting campaigns. The three particle size fractions of particulate matter were collected in Krakow, Poland. Fine fraction consists of particles of a diameter below 2.5 µm, medium is between 2.5 and 8 µm and coarse fraction contains particles above 8 µm. Elemental concentrations were evaluated for each sample. Following elements were measured by EDXRF method: K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Br, and Pb. During each sampling campaign meteorological parameters such as temperature, wind speed, wind direction, humidity were taken from the same place. The highest values of mass particulate matter showed results from January 2008 and April 2008. These were about 14 µg/m³ for fine fraction, 8 µg/m³ for medium and 16 µg/m³ for coarse fraction. The lowest values were observed in May 2007, they were 4, 6, 6 µg/m³, respectively. During the winter season the wind speed was low and particulate matter remained in the air in high concentrations. In May 2007 the speed of wind was higher, reaching 2–3 m/s. PM was blown away from the city from the direction of N–W. Measured concentrations of elements were low, they were below permissible values specified by EU. The coarse fraction concentrations of Ca, Mn, and Fe were higher and characterized by the same trend. These samples were collected when the wind speed was low and its direction was from south-east. As concentrations of Cr, Cu, and Zn were low, these elements did not come from the south-east direction of Krakow. Concentration of Br correlates to the concentration of Pb. It suggests that they came from the same source (vehicles fuels burning).