One-step synthesis of a fluorescein derivative and mechanistic studies

We report a convenient method for the one-step synthesis of a fluorescein derivative under acidic conditions. Mechanistic studies indicate that the acid-promoted condensation of o-tolualdehyde and 4-chlororesorcinol to form the fluorescein derivative proceeds through a cyclization-oxidation pathway while an alternative oxidation-cyclization pathway remains possible.     

One-step synthesis and crystal structure of a new monoterpene derivative with three different heteroatoms

The reaction of the oxime of verbenone, a bicyelie ketone, with sulfuric acid in acetonitrile gives a lactamsultone, which is readily separated and whose structure was demonstrated by x-ray diffraction structural analysis.Novosibirsk Institute of Organic Chemistry, Siberian Division, Russian Academy of Sciences, 630090 Novosibirsk and Institute of Physical Organic Chemistry, Academy of Sciences of Belarus, 220603 Minsk. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 704-707, May, 1995. Original article submitted April 24, 1995.     

Enantioselective deprotonation of meso-cycloheptanone derivative: application to the synthesis of a potential intermediate for pseudomonic acid B

[reaction: see text] A novel synthetic path to a potential intermediate for the synthesis of pseudomonic acid B was established by employing enantioselective deprotonation of a meso-cycloheptanone derivative bearing hydroxy groups at the 3,4,5,6-positions with lithium (S,S')-alpha,alpha'-dimethyldibenzylamide as a key step.     

One-step electrochemical synthesis of MoS2/graphene composite for supercapacitor application

Journal of Solid State Electrochemistry - In this study, an MoS2/graphene composite is fabricated from bulk MoS2 and graphite rod via a facile electrochemical exfoliation method. The as-prepared...     

One-step synthesis of silica@resorcinol-formaldehyde spheres and their application for the fabrication of polymer and carbon capsules

Core@shell spheres made up of a thin layer of resorcinol-formaldehyde enveloping a silica core were prepared by means of a one-step method under St?ber conditions. These spheres are used as a platform for the synthesis of carbon or polymeric capsules, and functionalized nanocomposites.     

Polymer supported calixarene derivative useful for solid-phase synthesis application

A calix[4]arene derivative has been anchored to carboxyl CPG and TentaGel supports by an easily cleavable ester bond and DMT groups allow a simple loading evaluation via UV-vis spectroscopy. The loading of the calixarene on TentaGel resin has also been estimated by HR-MAS NMR experiments. The potential of the polymer supported calixarenes (9 and 10) in solid phase synthesis has been tested by condensation of four thymine nucleotide units onto the upper rim of the calix[4]arene skeleton.     

Preparation and characterization of125I labeled progesterone derivatives for the development of a radioimmunoassay for progesterone

Preparation and purification of radioiodinated progesterone derivatives for the development of a radioimmunoassay of progesterone is described. We have standardized two procedures for preparing radioiodinated progesterone conjugate. In the first procedure¹²⁵I labeled histamine was conjugated to progesterone 11 hemisuccinate by the mixed anhydride method. In the secod procedure, tyrosyl methyl ester was conjugated to progesterone 11 hemisuccinate and iodination of the conjugate was carried out. Purification of the iodinated products was carried out by solvent extraction and thin layer chromatography techniques. The radiochemical purity of the tracers prepared by both methods were more than 95%. Labeled progesterone derivatives prepared were used for developing a radioimmunoassay procedure. The non-specific binding of the tracer was about 2–3%, while up to 80% binding could be obtained in the presence of excess antibody. The radioiodinated tracer could be used up to four months in the assay.     

Preparation and isolation of a homogeneous125I-cortisol derivative

Tracer specificity plays an important role in the radioimmunoassay (RIA) of steroid homones. In this paper, we describe the preparation and purification of¹²⁵I-labeled cortisol derivative with a carboxymethyloxime-histamine bridge. The investigation on the method of purification showed that HPLC could be adopted for the routine preparation of a pure, homogeneous tracer. The retention time observed in HPLC for¹²⁵I-histamine-CMO-cortisol conjugate could be used as an index for qualitative and quantitative assessments.     

Value of a saliva cortisol radioimmunoassay in the testing of the hypothalamic-pituitary-adrenal axis

Conclusions Saliva cortisol levels show significantly greater increases than serum cortisol after stimulation of the hypothalamic-pituitary-adrenal axis (insulin hypoglycaemia test, CRF-test and ACTH-test). In patients with Cushing's disease caused by chronic ACTH-stimulation, cortisol levels were relatively higher in saliva than in serum. The measurement of saliva cortisol seems of supplementary value in the testing of adrenocortical function.

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Wertigkeit eines Speichel-Cortisol-Radioimmunoassays bei der Funktionsprüfung der Hypothalamus-Hypophysen-Nebennierenrinden-Achse

     

One-step synthesis of a new heterocyclophane family

New macrocyclic compounds having two benzoxazine subunits joined by two ethylene bridges have been prepared by Mannich condensation of the appropriate 4-hydroxyphenylethylamine with an excess of formaldehyde. This is a general method for synthesising a new family of heterocyclophanes.     

Development of a non-competitive immunoassay for cortisol and its application to the analysis of saliva

A general method of performing non-competitive immunoassays for a low-molecular-mass analyte was developed and applied to cortisol determination in saliva samples. The method is based on the use of a “blocking reagent”, which is able to bind to antibody sites not occupied by the analyte, and in a stronger way than the analyte itself. When an enzyme-labelled analyte is added it substitutes the analyte in the antibody complex, but not the blocking reagent. The measured signal is linearly correlated to the concentration of the complex and, consequently, to the analyte concentration. The 3σ limit of detection (LOD, 0.2 nmol l⁻¹) obtained by the above method was 10 times lower than that obtained by the corresponding ELISA. As non-competitive immunoassays reported for small molecules up to now have been no more than just approaches, the suitability of the proposed assay for cortisol quantification in a real matrix was investigated. Human saliva was chosen as a matrix because of the need for very sensitive techniques to determine salivary cortisol content. The matrix effect was offset by performing the calibration experiments in acidic conditions (pH=5.6) and adding 0.1% of bovine serum albumin (BSA) to the buffer. In these conditions, the LOD was 1.4 nmol l⁻¹, which was adequate to measure normal levels of cortisol. Spiked samples were analysed and gave recoveries ranging from about 80 to 120%. Therefore, five subject samples, collected over 18 h showed salivary cortisol concentrations compatible with the circadian variation of reported normal values.     

Synthesis and preliminary evaluation of a novel 125I-labeled T140 analog for quantitation of CXCR4 expression

The aim of this study was to develop a radiopharmaceutical for the imaging of CXCR4-expressing tumors in vivo. For ¹²⁵I-labeling, ¹²⁵I-SIB was synthesized and conjugated with the ε-NH₂ group of Ac-TZ14011, a specific CXCR4 antagonist. The specific radioactivity of the product was 5 GBq/μmol and the radiochemical purity (RCP) was 96% (n = 3). After 6 h, the RCP of the product in PBS was 93%. The MCF-7 cell uptake of Ac-TZ14011 was rapid and high. Primary biodistribution studies indicated that ¹²⁵I-IB-Ac-TZ14011 was mainly excreted via the kidney, and further evaluation in mice with induced tumors was necessary.     

One-step synthesis of amino-dextran-protected gold and silver nanoparticles and its application in biosensors

A sensitive method for the detection of the lectin protein concanavalin A (Con A) was developed using amino-dextran (AD)-protected gold (AD-Au) and silver nanoparticles (AD-Ag) as sensitive optical probes. The AD-Au and AD-Ag nanoparticles were synthesized by directly applying amino-dextran as a reductive and protective reagent. The size of the nanoparticles could be altered by changing the molar ratio of AD to the metal salt. The amino-dextran bound to Con A by forming a 4:1 Au-Con A complex at neutral pH, and the nanoparticles were induced to aggregate by Con A. The absorption intensity of the nanoparticles decreased linearly with as the Con A concentration was increased from 3.85×10^–8 to 6.15×10^–7 M. The Au-Con A complex was dissociated by the disaccharide isomaltose, which has a higher affinities for Con A than Au; this competitive strategy could also be used to detect similar types of saccharides.     

双功能偶联剂SPC的一种新合成方法及其碘标记

放射性碘标记药物广泛用于医学检验及临床诊断和治疗中。放射性碘标记蛋白质不管是采用Ch-T、Iodogen直接标记方法还是采用Bolton-Hunter试剂间接标记方法,其存在的主要问题是标记物可能在体内严重脱碘[1,2]。为了克服这一问题,人们不断改进碘标记方法。其中,Zalutsky、W ilbur     

One-step synthesis of heteroaromatic-fused pyrrolidines via cyclopropane ring-opening reaction: application to the PKCbeta inhibitor JTT-010

A ring-opening reaction of cyclopropanes with five-membered heteroaromatics having a leaving group at C(2) was found to provide heteroaromatic-fused pyrrolidines in one step. This reaction was successfully applied to the synthesis of the protein kinase C-beta inhibitor JTT-010, which possesses a dihydropyrrolo[1,2-a]indole core.     

一步法制备钛负载介孔材料及其对CO2的吸附

以增溶了二氯二茂钛的P123胶束为模板,采用一步法得到了钛掺杂介孔材料Ti-SBA-15．FTIR、XRD、BET等测试结果显示Ti-SBA-15仍保持规整的孔道结构特征,样品经焙烧后茂环分解留下钛负载于介孔表面．对样品吸附CO2的测定结果表明,钛的负载有利于CO2的吸附,在N2气氛下焙烧的样品对C02的吸附性能显著提高,其中Ti-SBA-15（550-0．5-N2）对C02的最大吸附量为1．44mmolg^（-1）,钛在介孔材料中的存在形态对CO2吸附性能起决定性作用．