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A practicable method is described for the synthesis of 3‐acyl‐pyrazolo[1,5‐a]pyridines from N‐aminopyridines and easily available enaminones via a [3+2] cycloaddition. The reactions proceed well with a broad scope, without using additive (base or oxidant). [ABSTRACT FROM AUTHOR]

Keywords: sulfinate; sulfenylation; iodine; microwave heating; heterocycles; thiolation EN sulfinate sulfenylation iodine microwave heating heterocycles thiolation 1723 1726 4 08/18/23 20230901 NES 230901 Graph Organic sulfur compounds, especially thioethers, are prominent structural motifs in many bioactive natural products, pharmaceuticals, materials, and agrochemicals. [7] In 2018, the Song group developed a difunctionalization of an imidazopyridine by using a sodium sulfinate and iodine (Scheme 1)..[8] With the base and iodine, they obtained the sulfonylated product exclusively, whereas with iodine and a reducing agent (PPh SB 3 sb ), they obtained the sulfenylated product exclusively. However, the reaction of B 1a b with B 2a b in Et SB 2 sb O as a solvent under basic conditions at 100 °C for 20 hours gave the 3-phenylsulfonylated product B 4a b in only 50% conversion, along with 50% of the 3-iodo compound B 5 b (Table 1, entry 1). [Extracted from the article]

The first nucleophilic selenocyanation from selenium dioxide and malononitrile is described. This methodology produced a wide variety of selenocyanates from halides in moderate to excellent yields under mild conditions, highlighting the versatility and usefulness of this new source of nucleophilic selenocyanation. [ABSTRACT FROM AUTHOR]

A new method of deborylative selanylation using arylboronic acids and arylseleninic acids gave diaryl selenoethers and diarylselenoxide. The present approach requires only equimolar arylseleninic acid and led selectively to selenoethers or selenoxides depending on the solvent. The method is metal-free, base- or oxidant-free, efficient, and environmentally friendly. [ABSTRACT FROM AUTHOR]

The first ipso -selenocyanation of arylboronic acids is achieved using selenium dioxide and malononitrile under mild conditions. The reaction is successful even without metal or base in DMSO. The major advantages of this new method are an easy set-up, excellent yields, and the use of odorless and inexpensive selenium reagents. Basic conditions subsequently afford new access to diaryldiselenides in good yields without isolating the organoselenocyanate intermediates. [ABSTRACT FROM AUTHOR]

Series of solid-state emitters based on the D-π-A dipolar structure and featuring various electron-donor and electron-acceptor groups were designed, and their spectroscopic properties studied. From weak emission in dilute solutions, intense emissions in aggregated state (AIE) and in the crystalline state were obtained. Analysis in light of crystal structures obtained by X-ray diffraction revealed specific crystal packing and presence of long chain of emitting aggregates. This simple molecular engineering around the D-π-A dipolar structure provides easy access to a wide range of effective solid-state emitters allowing modulation of emission wavelengths up to the near infrared ( λ em reaching 735 and 768 nm for compound 2f and 3f bearing the strongest electron-withdrawing group). [ABSTRACT FROM AUTHOR]

The regioselective selenocyanation of imidazoheterocycles using triselenodicyanide at room temperature is reported. The electrophilic aromatic substitution of a broad range of substrates is promoted by the triselenodicyanide obtained by oxidative coupling of malononitrile and selenium dioxide, under an air atmosphere. The major advantages of the presented method are an easy set-up, excellent yields, short reaction times, use of odorless and inexpensive reagents and easy purification of the final products. [ABSTRACT FROM AUTHOR]

Abstract: Two new syntheses of benzyl C-glycosides have been developed. The first one involves an unprecedented oxa-Michael cyclisation and the second one relies on an efficient gold-catalysed ring-closure. [Copyright &y& Elsevier]

Abstract: A general method for the preparation of α-phenylselanyl enones is described. Phosphorus ylides react with these α-phenylselanyl enones in a 1,4-addition, leading to cyclopropanes and/or dihydrofurans, depending on the substitution pattern. This unusual reactivity is due to the phenylselanyl moiety, hindering the carbonyl of the enone and making it less prone to 1,2-additions or promoting conjugate addition by electronic effects. [Copyright &y& Elsevier]

Abstract: Ring-closing metathesis of bis-O,O-alkenyl ascorbic acid derivatives affords cyclic ethers in good yields which can be further converted by irradiation at 254nm into new polyoxacyclic structures according to a diastereoselective transannular [2+2] photocycloaddition. [Copyright &y& Elsevier]

We report here the first example of a one-pot synthesis of 2-(alkyl)arylbenzoselenazoles from N -(acetyl)benzoyl-2-iodoanilines. The reaction was carried out in the presence of Woollins’ reagent under microwave irradiation and resulted in moderate to good yields. [ABSTRACT FROM AUTHOR]

As part of our ongoing attempt to broaden the applications of the amidoxime moiety as a potential source of new antileishmanial agents, this study focuses on the product 4-(5-Benzyl-3-((4-fluorophenyl)sulfonyl)-5-methyl-4,5-dihydrofuran-2-yl)-2-nitrobenzamide. This unexpected amide was obtained in an 85% yield as the major product with a conventional amidoxime synthesis protocol (Ethanol/Na2CO3) involving the reaction of hydroxylamine and a nitrile group. The formation of this amide derivative instead of the expected amidoxime can be attributed to two complementary effects: the strong electron effect of the nitro group and the influence of ethanol, a polar protic solvent. Alternatively, the desired amidoxime derivative, 4-(5-benzyl-3-((4-fluorophenyl)sulfonyl)-5-methyl-4,5-dihydrofuran-2-yl)-N′-hydroxy-2-nitrobenzimidamide, was obtained in an 80% yield by an alternative protocol (DMSO/KOtBu). This original compound, featuring a nitro group in the ortho position to the amidoxime, will be further evaluated, both in the field of medicinal chemistry and in other relevant areas, highlighting an unusual method to access amidoximes from hindered substrates. [ABSTRACT FROM AUTHOR]

As part of our ongoing research into the antileishmanial properties of amidoxime derivatives, we report a preliminary assessment of the antiparasitic properties of a novel compound, diethyl (5-benzyl-2-(4-(N′-hydroxycarbamimidoyl)phenyl)-5-methyl-4,5-dihydrofuran-3-yl)phosphonate. This compound was evaluated in vitro for the first time against the promastigote form of Leishmania amazonensis. Compounds containing both amidoxime and phosphonyl functional groups in dihydrofuran scaffolds are relatively rare, despite the extensive study of this heterocycle in various biological applications. Therefore, this work makes a valuable contribution to the fight against Leishmania spp. as a neglected disease. The cyclized 4,5-dihydrofuran intermediate scaffold was obtained via a three-step synthetic route that had previously been developed for accessing other derivatives, including the sulfone moiety. This synthesis was performed using a manganese-based free radical oxidative method under microwave irradiation. The intermediary 4,5-dihydrofuran, which included a nitrile group, tolerated the subsequent reaction with hydroxylamine hydrochloride, resulting in the formation of the target product. The target compound showed moderate activity in vitro against the promastigote form of L. amazonensis (IC50 = 91.1 µM). [ABSTRACT FROM AUTHOR]

Aminoquinolinium salts, aminoquinazolinium salts, N, N '-bridging alkylation, amination, nucleophilic aromatic substitution An attempted I N i , I N i '-alkylation of two molecules of 4-chloro-6,7-dimethoxyquinoline ( B 2 b ) with a propyl bridge resulted in an inseparable mixture of the expected dimer B 26 b , the monosubstituted I N i -(3-halopropyl)quinolinium salts B 24 b and B 25 b , and the protonated 4-halo-6,7-dimethoxyquinolinium salt B 23 b , in addition to halogen-exchange products. Keywords: aminoquinolinium salts; aminoquinazolinium salts; N, N '-bridging alkylation; amination; nucleophilic aromatic substitution EN aminoquinolinium salts aminoquinazolinium salts N, N '-bridging alkylation amination nucleophilic aromatic substitution 1685 1688 4 08/18/23 20230901 NES 230901 Graph Most drugs available on the market, as well as pharmacologically active molecules in development, have heterocyclic pharmacophoric structures, often with quinoline or quinazoline nuclei. [Extracted from the article]

A sequential one-pot, simple and convenient method is described for the synthesis of 3-selenocyanato-4H-chromen-4-ones by addition, first of DMF-DMA and then of triselenodicyanide as electrophile. [ABSTRACT FROM AUTHOR]

A practical and efficient synthesis of 2,4,6,8-tetrasubstituted quinazolines through one-pot chemoselective sequential bis- SNAr/bis-Suzuki-Miyaura reactions under microwave irradiation is presented. The bis-SNAr reaction occurs selectively at the C-2 and C-4 positions of 6,8-dibromo-2,4-dichloroquinazoline and the bis- Suzuki-Miyaura cross-coupling at C-6 and C-8. This procedure affords convergent synthesis of polysubstituted quinazoline derivatives in high yields in very few steps and tolerates a wide range of boronic acids and amines. [ABSTRACT FROM AUTHOR]

Fifteen heptamethine dyes in which a tricyanofuran acceptor is linked to donors of different strengths were synthesized, and their absorption, thermal, electrochemical, and second-order nonlinear optical properties were investigated. While the variation of the peripheral bulky substituents allowed a decrease of the intermolecular interactions in the solid state, subtle engineering of the heterocyclic donor provided dyes with electronic structures that varied between dipolar and cyanine-like (i.e., with little bond length alternation and with ground and excited states having similar dipole moment) and remarkably high quadratic hyperpolarizabilities (μβ1.9) of up to 115000 × 10-48 esu. [ABSTRACT FROM AUTHOR]

Abstract: Organic electron donors (OEDs) are powerful reducing agents recognized for their potential in the reduction of challenging substrates and in original applications. Nonetheless, their low stability in atmospheric oxygen or over time complicates their manipulation and storage. To overcome these constraints and enhance OED practicality, new air‐ and moisture‐stable aminopyridinium carboxylate and carbonate precursors were synthesized and thermally activated to generate the potent electron donor in situ. Carboxylate adducts proved to be excellent latent OED systems, enabling the facile and efficient reduction of challenging substrates. Their reduction properties were correlated to their structural characteristics by thermogravimetric and spectroscopic analysis. [ABSTRACT FROM AUTHOR]

Abstract: Organic electron donors (OEDs) are powerful reducing agents recognized for their potential in the reduction of challenging substrates and in original applications. Nonetheless, their low stability in atmospheric oxygen or over time complicates their manipulation and storage. To overcome these constraints and enhance OED practicality, new air‐ and moisture‐stable aminopyridinium carboxylate and carbonate precursors were synthesized and thermally activated to generate the potent electron donor in situ. Carboxylate adducts proved to be excellent latent OED systems, enabling the facile and efficient reduction of challenging substrates. Their reduction properties were correlated to their structural characteristics by thermogravimetric and spectroscopic analysis. [ABSTRACT FROM AUTHOR]

The use of visible absorbing and fluorescent tags for sensing and structural analysis of carbohydrates is a promising route in a variety of medical, diagnostic, and therapeutic contexts. Here we report an easy method for covalent attachment of nonfluorescent push–pull chromophores based on the 4-cyano-5-dicyanomethylene-2-oxo-3-pyrroline ring to carbohydrate moieties. The impact of sugar grafting on the optical properties of the push–pull chromophore in the gas phase and in solution was investigated by absorption and action spectroscopy and theoretical methods. The labeled sugars efficiently absorb photons in the visible range, as demonstrated by their intense photodissociation in a quadrupole ion trap. A strong blue shift (−70 nm) of the gas-phase photodissociation intensity maximum is observed upon sugar grafting, whereas no such effect is visible on the solution absorption spectra. Molecular dynamics simulations of labeled maltose in the gas phase describe strong interactions between the sulfonated chromophore and the carbohydrate, which lead to cyclic conformations. These are not observed in the simulations with explicit solvation. Time-dependent density functional theory (TD-DFT) calculations on model molecules permit us to attribute the observed shift to the formation of such cyclic conformations and to the displacement of the negative charge relative to the aromatic moiety of the chromophore. [ABSTRACT FROM AUTHOR]