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Magnetic nanoparticles (MNPs) based on magnetite (Fe3O4) are attractive catalyst supports due to their high surface area, easy preparation, and facile separation, but they lack stability in acidic reaction media. The search for MNPs stable in oxidative acidic reaction media is a necessity if one wants to combine the advantages of MNPs as catalyst supports with those of iodine(III) reagents being environmentally benign oxidizers. In this work, immobilized iodophenyl organocatalysts on magnetite support (IMNPs) were obtained by crossed-linking polymerization of 4-iodostyrene with 1,4-divinylbenzene in the presence of MNPs. The obtained IMNPs were characterized by TGA, IR, SEM, STEM, and HAADF to gain information on catalyst morphology, average particle size (80–100 nm), and their core–shell structure. IMNP-catalysts tested in (i) the α-tosyloxylation of propiophenone 1 with meta-chloroperbenzoic acid (m-CPBA) and (ii) in the oxidation of 9,10-dimethoxyanthracene 3 with Oxone® as the side-oxidant showed a similar performance as reactions using stoichiometric amounts of iodophenyl. The developed IMNPs withstand strong acidic conditions and serve as reusable organocatalysts. They are recyclable up to four times for repeated organocatalytic oxidations with rates of recovery of 80–92%. This is the first example of a—(4-iodophenyl)polystyrene shell—magnetite core-structured organocatalyst withstanding strong acidic reaction conditions. [ABSTRACT FROM AUTHOR]

A novel synthesis strategy to access 2-alkoxyquinoline derivatives via a palladium-driven cascade reaction is disclosed. Unlike classic methods based on the alkylation of 2-quinolones with alkyl halides, the present method benefits from the de novo assembly of the quinoline core starting from 1,3-butadiynamides. Palladium-catalyzed reaction cascades with N-(2-iodophenyl)-N-tosyl-1,3-butadiynamides and primary alcohols as external nucleophiles proceed under mild reaction conditions and selectively deliver a variety of differently functionalized 4-alkenyl 2-alkoxyquinolines in a single batch transformation. [ABSTRACT FROM AUTHOR]

1,3-butadiynamides—the ethynylogous variants of ynamides—receive considerable attention as precursors of complex molecular scaffolds for organic and heterocyclic chemistry. The synthetic potential of these C4-building blocks reveals itself in sophisticated transition-metal catalyzed annulation reactions and in metal-free or silver-mediated HDDA (Hexa-dehydro-Diels–Alder) cycloadditions. 1,3-Butadiynamides also gain significance as optoelectronic materials and in less explored views on their unique helical twisted frontier molecular orbitals (Hel-FMOs). The present account summarizes different methodologies for the synthesis of 1,3-butadiynamides followed by the description of their molecular structure and electronic properties. Finally, the surprisingly rich chemistry of 1,3-butadiynamides as versatile C4-building blocks in heterocyclic chemistry is reviewed by compiling their exciting reactivity, specificity and opportunities for organic synthesis. Besides chemical transformations and use in synthesis, a focus is set on the mechanistic understanding of the chemistry of 1,3-butadiynamides—suggesting that 1,3-butadiynamides are not just simple alkynes. These ethynylogous variants of ynamides have their own molecular character and chemical reactivity and reflect a new class of remarkably useful compounds. [ABSTRACT FROM AUTHOR]

Research has been conducted on the alpha-sulfinyl carbonyl compounds. The alkylation of the enantiopure alpha-sulfinyl thioacetamide's lithium enolate with allyl bromides carried out at the vinylic position is described.

Research has been conducted on the ketene aminoacetals which bear enantiopure alkylsulfinyl substituent. The preparation of these aminoacetals from the (R)-2-cycloxylsulfinyl-N,N-dimethylethanethioamide has been carried out and the results indicate that the double bonds have undergone a Claisen rearrangement after being heated at the tetrahydrofuran reflux.

2‐N‐aminoquinazolines were prepared by consecutive SNAr functionalization. X‐ray structures display the nitrogen lone pair of the 2‐N‐morpholino group in conjugation with the electron deficient quinazoline core and thus representing electronic push‐pull systems. 2‐N‐aminoquinazolines show a positive solvatochromism and are fluorescent in solution and in solid state with quantum yields up to 0.73. Increase in electron donor strength of the 2‐amino substituent causes a red‐shift of the intramolecular charge transfer (ICT) band (300–400 nm); whereas the photoluminescence emission maxima (350–450 nm) is also red‐shifted significantly along with an enhancement in photoluminescence efficiency. HOMO‐LUMO energies were estimated by a combination of electrochemical and photophysical methods and correlate well to those obtained by computational methods. ICT properties are theoretically attributed to an excitation to Rydberg‐MO in SAC‐CI method, which can be interpreted as n‐π* excitation. 7‐Amino‐2‐N‐morpholino‐4‐methoxyquinazoline responds to acidic conditions with significant increases in photoluminescence intensity revealing a new turn‐on/off fluorescence probe. [ABSTRACT FROM AUTHOR]

We report the preparation of phosphiranium salts by quaternarization of phosphiranes, a class of sensitive, highly strained, and poorly nucleophilic cyclic phosphines. High-yielding introduction of a varied set of alkyl groups including methylene ester arms was accomplished under mild conditions. A Cu-catalyzed electrophilic arylation of phosphiranes using diaryl iodonium reagents was also achieved to yield unprecedented P , P -diaryl phosphiranium salts with good efficiency. [ABSTRACT FROM AUTHOR]

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Triazoles are an important class of photonucleases that produce intermediates capable of hydrogen abstraction for DNA cleavage. The ability to convert circular supercoiled DNA to circular relaxed DNA and linear DNA makes triazoles effective DNA cleaving agents. The photochemical transformation of benzotriazole at 77 degree kelvin produces a singlet intermediate. The intermediate undergoes inter-system to form a triplet that cleaves DNA by hydrogen abstraction. Triazoles show cleavage selectivity for guanine amino acids.

meso-Bisalkynes and alkenes have potential as substrates for desymmetrization processes. The preparation of several meso-bis(1'-hydroxy-2'-propynyl)benzenes and their derivatives from phthalalde-hydes using inexpensive and readily available reagents is described. [ABSTRACT FROM AUTHOR]