A facile synthesis of α-substituted thiophenes from a functionalized 2-aminothiophene by homo- and cross-coupling reactions

A series of new α-substituted thiophenes with elongated π-conjugation are prepared by homo- and cross-coupling reactions. An efficient one-step synthesis of a key intermediate, a substituted 2-iodothiophene, via aprotic diazotization of a Gewald-like 2-aminothiophene is reported.     

Cytochalasin B (phomin): degradation reactions and cyclization of B-cytochalasinic acid to 21,22-dihydro-isocytochalasin A (author's transl)]

Cytochalasin B (Phomin): Degradation Reactions and Cyclization of B-Cytochalasinic Acid to 21,22-Dihydro-Isocytochalasin A Treatment of the γ-lacton 5 , a transformation product of cytochalasin B (phomin) ( 1 ), with OsO₄ gave the dihydroxy derivatives 6 and 7 . Cleavage of the former by NaIO₄ in aqueous methanol yielded a mixture of the dimethylacetal 10 and the unsaturated aldehyde 11 , which are potential intermediates for a total synthesis of cytochalasins. Cytochalasin B ( 1 ) was hydrolysed with NaOH in aqueous dioxane to B-cytochalasinic acid ( 14 ). Recyclization of 14 using the Mukaiyama-Corey method [19] [20] did not yield cytochalasin B ( 1 ) but the isomeric 21,22-dihydro-isocytochalasin A ( 18 ). Treatment of 14 according to Gerlach [21] yielded the phthalimidine 19 .     

New Subinterval Selection Criteria for Interval Global Optimization

The theoretical convergence properties of interval global optimization algorithms that select the next subinterval to be subdivided according to a new class of interval selection criteria are investigated. The latter are based on variants of the RejectIndex: , a recently thoroughly studied indicator, that can quite reliably show which subinterval is close to a global minimizer point. Extensive numerical tests on 40 problems confirm that substantial improvements can be achieved both on simple and sophisticated algorithms by the new method (utilizing the known minimum value), and that these improvements are larger when hard problems are to be solved.     

Generalized Subinterval Selection Criteria for Interval Global Optimization

The convergence properties of interval global optimization algorithms are studied which select the next subinterval to be subdivided with the largest value of the indicator pf(f _k ,X)=(f _k ? $\underline F $ (X))/( $\overline F $ (X)? $\underline F $ (X)). This time the more general case is investigated, when the global minimum value is unknown, and thus its estimation f _k in the iteration k has an important role. A sharp necessary and sufficient condition is given on the f _k values approximating the global minimum value that ensure convergence of the optimization algorithm. The new theoretical result enables new, more efficient implementations that utilize the advantages of the pf ^* based interval selection rule, even for the more general case when no reliable estimation of the global minimum value is available.     

Thermal decomposition of maltitol spreads

The purpose of this study is to research the thermal properties of spreads with maltitol. Thermal characteristics of spreads depend on process parameters (temperature, mixer speed rotation). Spreads are produced at different temperatures (30, 35, and 40 °C) and mixer speed rotation (1, 1.33, and 1.67 Hz). The thermogravimetric method shows the peak position and determinate the spread composition. The temperature decomposition of sucrose and maltitol is two stages (two peaks), and palm fat has a single stage decomposition (one peak). Maltitol peak is dominant for spreads containing 100 and 70 % maltitol as a sweetener. This peak is sharper than sucrose peak and the inflection point is more expressed. Shape and the position of these peaks in spreads are modified. Peaks of maltitol, palm fat, and sucrose in spreads are lower and wider because of the grinding process and the interaction between spread ingredients. Increasing the process parameters (temperature, mixer speed rotation), temperatures of these peaks are higher (closer to temperature peak of pure ingredients). The dominant parameter is mixer speed rotation. The most thermally stable spreads with any amount of maltitol are produced at a temperature of 40 °C and high mixer speed rotation (1.33 and 1.67 Hz), while the least stable maltitol spreads are produced at minimum process parameters (30 °C, 1 Hz).     

A validated method for measurement of serum total,serum free,and salivary cortisol,using high-performance liquid chromatography coupled with high-resolutionESI-TOF mass spectrometry

Blood cortisol level is routinely analysed in laboratory medicine, but the immunoassays in widespread use have the disadvantage of cross-reactivity with some commonly used steroid drugs. Mass spectrometry has become a method of increasing importance for cortisol estimation. However, current methods do not offer the option of accurate mass identification. Our objective was to develop a mass spectrometry method to analyse salivary, serum total, and serum free cortisol via accurate mass identification. The analysis was performed on a Bruker micrOTOF high-resolution mass spectrometer. Sample preparation involved protein precipitation, serum ultrafiltration, and solid-phase extraction. Limit of quantification was 12.5 nmol L^?1 for total cortisol, 440 pmol L^?1 for serum ultrafiltrate, and 600 pmol L^?1 for saliva. Average intra-assay variation was 4.7 %, and inter-assay variation was 6.6 %. Mass accuracy was <2.5 ppm. Serum total cortisol levels were in the range 35.6–1088 nmol L^?1, and serum free cortisol levels were in the range 0.5–12.4 nmol L^?1. Salivary cortisol levels were in the range 0.7–10.4 nmol L^?1. Mass accuracy was equal to or below 2.5 ppm, resulting in a mass error less than 1 mDa and thus providing high specificity. We did not observe any interference with routinely used steroidal drugs. The method is capable of specific cortisol quantification in different matrices on the basis of accurate mass identification.     

Synthesis of π-conjugated thiophenes starting from substituted 3-oxopropanenitriles via Gewald reaction

This paper describes the synthesis of β-aryl and β-heteroaryl substituted 2-aminothiophenes as a novel class of building blocks in oligo- and polythiophenes. The synthesis was carried out in two steps, involving synthesis of substituted 3-oxopropanenitrile intermediates, followed by the Gewald reaction.     

Reliable Numerical Computation in Civil Engineering

Civil engineering is a field – as are many other engineering sciences – where most of the methods used for solving optimization problems are based on experience and experiments, and models using local information, but drawn from global models. The present work outlines an interesting class of problems from this field, and initiates some possible ways to solve those problems utilizing the wide tool capabilities of interval arithmetic for error handling and interval branch-and-bound algorithms to solve the original or modified industrial models automating civil engineers' work. The investigations are in the first state but are promising both in a theoretical and in a practical sense.