Pyridinethiones. XI. Diastereoselective aldol condensations with 2(1H)-pyridones, 2(1H)-pyridinethiones,and the crystal structure of 3-(1-hydroxy-2-methyl-3-oxo-3-(4-chlorophenyl)propyl-1-isoprpyl-2(1H)-pyridinethione

Aldol condensation of 3-formyl-2(1H)-pyridinethiones and the corresponding pyridones with ketones such as acetophenones in aqueous base yields 3-hydroxy-1-propanones in high yields. Reaction with propiophenone showed this reaction to be highly diastereoselective as only the erythro-isomer is formed at room temperature. This assignment was based on an X-ray crystallographic investigation of the compound given in the title. Aldol condensations of a number of related 3-acetyl-2(1H)-pyridinethiones with benzaldehyde yielded the corresponding trans-vinyl ketones.     

Engineering of an all‐heteronuclear 5‐qubit NMR quantum computer

The realization of an all‐heteronuclear 5‐qubit nuclear magnetic resonance quantum computer is reported, from the design and synthesis of a suitable molecule through the engineering of a prototype 6‐channel probe head. Full control over the quantum computer is shown by a benchmark experiment. Copyright © 2015 John Wiley & Sons, Ltd.     

On the Redox Reaction of 1,2-Bis(diphenylphosphino) Alkanes Toward o-, and p-Quinones

Abstract

The reaction of 1,2-bis(diphenylphosphino)ethane with substituted o-benzo-quinones afforded new bis(6-hydroxycyclohexa-2,4-dienone) derivatives. Treatment of the same reagent with o-naphthoquinone, phenanthrenequinone, and acenaphthenequinone gave the respective bis(diphenylphosphoryl)ethylidenes or diacenaphthylenone derivatives. On the other hand, p-quinones react with 1,2-bis(diphenylphosphino)methane to yield the corresponding 4-hydroxycyclohexa-2,5-dien-1-ones. Possible reaction mechanisms are considered and the structural assignments are based on compatible analytical and spectroscopic data.     

THERMOLYSIS AND PHOTOLYSIS OF SOME THIOUREA DERIVATIVES (PART I)

Abstract

Thermolysis of N-benzoyl-N′-phenylthiourea (BPTU) on heating in air at 230°C gives NH₃, H₂S, benzaldehyde, benzil, aniline, azobenzene, benzamide, benzanilide, phenylisothiocyanate, phenyl-cyanamide, thiocarbanilide and benzoylisothiocyanate, whereas thermolysis of N-benzoy1-N′-benzylthiourea (BBTU) affords NH₃, H₂S, benzaldehyde, benzil, toluene, bibenzyl, stilbene, benzamide, cyanamide, benzylisothiocyanate, benzoylthiourea and benzoylisothiocyanate. Thermolysis of N-benzoyl-N′-α-naphthylthiourea (BNTU) under the same conditions gives NH₃, H₂S. benzaldehyde, benzil, benzamide, α-naphthylisothiocyanate, α-naphthanilide, α-naphthylcyanamide. benzoylisothiocyanate, α-naphthylamine and N,N′-di-α,α′-naphthylthiourea. Analogous results were also obtained on photolysis of (BFTU), (BBTU) and (BNTU) with the exception of NH₃, and the photodegradation products of phenylthiourea, benzylthiourea and a-naphthylthiourea respectively. The main feature of these pyrolyses is the homolysis of the amide and thioamide bonds providing free radicals that undergo different reactions involving H-abstraction, dimerization, coupling, fragmentation, rearrangement and disproportionation to yield the identified products.     

Determination of molecular configuration by debye length modulation

Silicon nanowire field effect transistors (FETs) have emerged as ultrasensitive, label-free biodetectors that operate by sensing bound surface charge. However, the ionic strength of the environment (i.e., the Debye length of the solution) dictates the effective magnitude of the surface charge. Here, we show that control of the Debye length determines the spatial extent of sensed bound surface charge on the sensor. We apply this technique to different methods of antibody immobilization, demonstrating different effective distances of induced charge from the sensor surface.     

ADM-Padé solutions for generalized Burgers and Burgers-Huxley systems with two coupled equations

We present an approximate numerical solution to generalized Burgers and Burgers-Huxley systems with two coupled equations using the ADM-Padé technique which is a combination of the Adomian decomposition method and Padé approximation. The Padé technique is used to enhance the accuracy and speed up the convergence rate of the truncated series solution produced by the ADM. Results are given in graphical form for explicit examples of the two systems.     

On non-commutative noetherian local rings, non-commutative geometry and particle physics

In this note we find the necessary and sufficient conditions which implies that the Dilworth number of non-commutative noetherian local ring equals one. In addition we discuss briefly connections to non-commutative geometry, theory and particle physics.     

Ionization and electroreduction of some benzthiazin-4-one azodyes

pKa values of a series of the titled compounds (2 a–g) together with a model compound3 have been determined spectrophotometrically in alcoholic buffered media. These values were correlated to different sets. The polarographic behaviour of the parent2 a and its nitro derivative2 g was studied in detail. The obtained data showed that2 a is reduced via a 2-electron process to the corresponding hydrazo from which was stabilized through hydrogen bonding.

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Ionisierung und Elektroreduktion einiger Benzthiazin-4-on-Azofarbstoffe

Zusammenfassung Es wurden diepKa-Werte einer Serie der Titelverbindungen (2 a–g) zusammen mit einer Modellverbindung3 spektrophotometrisch in alkoholischer gepufferter Lösung bestimmt. Diese Werte wurden mit verschiedenen Sets von -Werten korreliert. Das polarographische Verhalten der Stammverbindung2 a und deren Nitroderivat2 g wurde im Detail untersucht. Die Daten zeigen, daß2 a über einen Zweielektronenprozeß zur entsprechenden Hydrazo-Verbindung reduziert wird, die durch Wasserstoffbrücken stabilisiert ist.

     

Multivariate experimental design: towards more reliable electrochemical detection

Design of an experiment approach has recently become an urgent requirement for different experimental measurements. Not only owing to the increased expenses for purchasing chemicals and equipment but also to reduce time required to conduct several one-variable at a time experiments to optimize the operating conditions of an experimental design. Design of experiments has excellent applicability in the analytical process related to method development based on multiple variants used for pharmaceutical, food, and environmental analysis. Application of experimental design has become effective to identify and optimize the significant factors and to achieve adequate results using few experimental trials. Electrochemical sensors represent a class of fast, reliable, and economic tools in analytical chemistry, with vast applicability to different fields. This review aims at presenting the most recently used screening and optimization designs during (2019–2021) for the fabrication and operation variables of electrochemical sensors and how can they be efficiently correlated.