Automated Deconvolution of Overlapped Ion Mobility Profiles

Presence of unresolved ion mobility (IM) profiles limits the efficient utilization of IM mass spectrometry (IM-MS) systems for isomer differentiation. Here, we introduce an automated ion mobility deconvolution (AIMD) computer software for streamlined deconvolution of overlapped IM-MS profiles. AIMD is based on a previously reported post-IM/collision-induced dissociation (CID) deconvolution approach [J. Am. Soc. Mass Spectrom. 23, 1873 (2012)] and, unlike the previously reported manual approach, it does not require resampling of post-IM/CID data. A novel data preprocessing approach is utilized to improve the accuracy and efficiency of the deconvolution process. Results from AIMD analysis of overlapped IM profiles of data from (1) Waters Synapt G1 for a binary mixture of isomeric peptides (amino acid sequences: GRGDS and SDGRG) and (2) Waters Synapt G2-S for a binary mixture of isomeric trisaccharides (raffinose and isomaltotriose) are presented. Graphical Abstract

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Microwave‐Assisted Aromatization of 1,3,5‐Trisubstituted 2‐Pyrazolines by Bi(NO3)3 · 5H2O,as a Novel and Convenient Oxidizing Agent

Abstract

Bismuth(III) nitrate pentahydrate, Bi(NO₃)₃?·?5H₂O, has been used as a mild, efficient, and inexpensive oxidant for the oxidative aromatization of several 1,3,5‐trisubstituted 2‐pyrazolines to pyrazoles in acetic acid under microwave irradiation with good to excellent yields.     

CuBr-Catalyzed Oxidation/Coupling: An Efficient and Applicable Strategy for the Synthesis of 2-Aryl Benzimidazoles from 1-Fluoro-2-nitrobenzene and Benzylamines

A novel and efficient route has been developed for the synthesis of benzimidazole derivatives via ligand-free CuBr-catalyzed oxidation and cyclization of 1,2-diamines derived from 1-fluoro-2-nitrobenzene and different arylamines as starting materials.     

One‐Pot Synthesis of Sulfonamides and Sulfonyl Azides from Thiols using Chloramine‐T

A convenient synthesis of sulfonamides and sulfonyl azides from thiols is described. In situ preparation of sulfonyl chlorides from thiols was accomplished by oxidation with chloramine‐T (=N‐chlorotosylamide=N‐chloro‐4‐methylbenzenesulfonamide), tetrabutylammonium chloride (Bu₄NCl), and H₂O. The sulfonyl chlorides were then further allowed to react with excess amine or NaN₃ in the same pot.     

Measurement of the thermal conductivity of MWCNT-CuO/water hybrid nanofluid using artificial neural networks (ANNs)

Journal of Thermal Analysis and Calorimetry - In this paper, artificial neural networks (ANNs) are developed to predict the thermal conductivity ( $$k_{\text{nf}}$$ ) of multi-walled carbon...     

Mg(OH)2 nanostructures using impure brine: optimization of synthesis parameters by Taguchi robust design and study of optical properties

Research on Chemical Intermediates - In this research, high purity magnesium hydroxide (Mg(OH)2) nanoparticles were successfully synthesized by the wet chemical precipitation method from an impure...     

New insight into experimental and theoretical mechanistic study on a green synthesis of functionalized 4H-chromenes using magnetic nanoparticle catalyst

A green synthesis of functionalized 4H-chromenes using one-pot, three-component reaction of salicylaldehyde ( 1 ), active methylene ( 2 ), and carbon-based nucleophile ( 3 ) using Fe₃O₄@CONa nanoparticles in water has been performed at 60°C. The Fe₃O₄@CONa nanoparticle as an efficient, green, and magnetically reusable heterogeneous catalyst was applied in these reactions up to the nine runs. Green catalyst and solvent, short reaction time, high product yields, as well as simple work-up procedure were found as some advantages of this methodology. The density functional theory calculations were applied to all-inclusive perception of the one-pot, three-component reaction mechanism. The most reactions progressed through the following route: (a) nucleophilic addition of 2 to 1 ; (b) ring closing, dehydration; (c) nucleophilic substitution of 3 (2-naphtol, 4-hydroxycumarin) to intermediate. Sometimes mechanism mutated to: (a) nucleophilic addition of 3 (indole, 2-methylindole) to 1 , and dehydration; (b) nucleophilic addition of 2 to intermediate; and (c) ring closing, and dehydration. The frontier molecular orbitals, NBO analyses, molecular electrostatic potential of reactants, and intermediates confirmed the proposal mechanisms. Theoretical study could be so helpful to pick out suitable reactants of the reaction.     

Uniform-cost inverse absolute and vertex center location problems with edge length variations on trees

This article considers the inverse absolute and the inverse vertex 1-center location problems with uniform cost coefficients on a tree network T with n+1 vertices. The aim is to change (increase or reduce) the edge lengths at minimum total cost with respect to given modification bounds such that a prespecified vertex s becomes an absolute (or a vertex) 1-center under the new edge lengths. First an O(nlogn) time method for solving the height balancing problem with uniform costs is described. In this problem the height of two given rooted trees is equalized by decreasing the height of one tree and increasing the height of the second rooted tree at minimum cost. Using this result a combinatorial O(nlogn) time algorithm is designed for the uniform-cost inverse absolute 1-center location problem on tree T. Finally, the uniform-cost inverse vertex 1-center location problem on T is investigated. It is shown that the problem can be solved in O(nlogn) time if all modified edge lengths remain positive. Dropping this condition, the general model can be solved in O(r_vnlogn) time where the parameter r_v is bounded by ⌈n/2⌉. This corrects an earlier result of Yang and Zhang.     

On the existence of 3-way k-homogeneous Latin trades

A $\mu$-way Latin trade of volume $s$ is a collection of $\mu$ partial Latin squares $T_1,T_2,\dots ,T_{\mu }$, containing exactly the same $s$ filled cells, such that, if cell $(i,j)$ is filled, it contains a different entry in each of the $\mu$ partial Latin squares, and such that row $i$ in each of the $\mu$ partial Latin squares contains, set-wise, the same symbols, and column $j$ likewise. It is called a $\mu$-way$k$-homogeneous Latin trade if, in each row and each column, $T_r$, for $1\le r\le \mu$, contains exactly $k$ elements, and each element appears in $T_r$ exactly $k$ times. It is also denoted as a $(\mu ,k,m)$ Latin trade, where $m$ is the size of the partial Latin squares.We introduce some general constructions for $\mu$-way $k$-homogeneous Latin trades, and specifically show that, for all $k\le m$, $6\le k\le 13$, and $k=15$, and for all $k\le m$, $k=4,5$ (except for four specific values), a $3$-way $k$-homogeneous Latin trade of volume $km$ exists. We also show that there is no $(3,4,6)$ Latin trade and there is no $(3,4,7)$ Latin trade. Finally, we present general results on the existence of $3$-way $k$-homogeneous Latin trades for some modulo classes of $m$.     

Organic Electrosynthesis as a New Facile and Green Method for One‐pot Synthesis of Nanosized Particles of Octahydro‐imidazo[1,2‐a]quinolin‐6‐one Derivatives via a Multicomponent Reaction

Organic electrosynthesis as a new facile and green method was applied for one‐pot synthesis of octahydro‐imidazo[1,2‐a]quinolin‐6‐one derivatives, via a three component condensation of a dimedone, an aldehyde and 2‐(nitromethylene)imidazolidine in propanol in an undivided cell in the presence of sodium bromide as an electrolyte at room temperature. In this study, the anion of dimedone that was produced on the cathode reacted with aromatic aldehydes through the Knoevenagel reaction and then the product condensed with 2‐(nitromethylene)imidazolidine that resulted in a highly efficient formation of octahydro‐imidazo[1,2‐a]quinolin‐6‐one with 50–96% substance yields.