Metal-free efficient synthesis of aryl sulfonamides from N-hydroxy sulfonamide and amines.

A simple and novel approach has been developed for the synthesis of sulfonamides from N-hydroxy sulfonamide. Notably, the iodine-tert-butyl hydroperoxide (TBHP) system efficiently promoted the sulfonylation reactions of N-hydroxy sulfonamides and amines via the oxidative cleavage of an S-N bond. A variety of aryl sulfonamides were prepared in moderate to good yields using readily available starting materials and the biomass-derived 2-MeTHF solvent. The present method has the advantages of using metal-free reagents, an eco-friendly medium, cost-effective reagents, wide substrate scope, and mild conditions.

Metal-free oxidative coupling of aryl acetylene with elemental sulphur and amines: facile access to α-ketothioamides.

A simple and efficient oxidative coupling of aromatic alkynes with elemental sulphur and secondary amines has been reported. The iodine/DMSO system easily promoted the transformations, affording thioglyoxamides via C-S, C-O, and C-N bond formations. In this context, acetylenic C-H bond oxidation has occurred through iodination, leading to the desired products. Moreover, this metal-free, one-pot protocol is accomplished by using readily available starting materials, without external oxidants, and under aerobic conditions, providing a variety of α-ketothioamide compounds in moderate to good yields.

Copper-catalysed chemoselective C-OH bond activation of N-benzoyl cytosine: facile access to 2-(dimethylamino)pyrimidine.

A novel method for the direct amination of N-benzoyl cytosine has been developed, giving access to 2-(dimethylamino)pyrimidine derivatives. A copper(II) catalyst and tert-butyl hydroperoxide easily promote the selective amination process that proceeds via C-OH bond activation. This practical approach can utilize different formamide molecules, N,N-dimethylformamide and N,N-diethylformamide, as efficient amino (-NMe2, -NEt2) sources. Moreover, the facile nature of the procedure, its broad tolerance of aliphatic and aromatic substrates, the high yields and ease of separation of the products, and the fact that it can be conducted under aerobic conditions are all notable advantages of the present protocol.

Copper catalysed oxidative cascade deamination/cyclization of vinyl azide and benzylamine for the synthesis of 2,4,6-triarylpyridines.

A highly efficient one-pot method for the synthesis of 2,4,6-triaryl pyridines has been developed via cascade deamination and annulation. Copper triflate and molecular iodine easily promoted the oxidative cyclization reaction of vinyl azide and benzylamine to access a wide variety of substituted pyridine substrates under an oxygen atmosphere. The presence of benzyl amine enables the cyclization process by providing the aryl functionality and the nitrogen source. Moreover, a broad range of substrates with good functional group tolerance, avoidance of external oxidants, excellent product yields, operational simplicity and mild conditions are the notable advantages of the present protocol.

I2/TBHP-mediated oxidative cascade cyclization of vinyl azide and benzylamine to construct 2,5-disubstituted oxazoles.

A one-pot facile synthesis of disubstituted oxazoles has been achieved from vinyl azide and benzylamine. A coherent mixture of iodine and tert-butyl hydroperoxide (TBHP) efficiently promoted oxidative cascade cyclization to construct 2,5-disubstituted oxazoles under aerobic conditions. Notably, the oxidative cyclization involves feasible C(sp3)-functionalization with the elimination of the azide group as the intermediate step. In consequence, the consecutive C-N and C-O bond formations lead to a variety of disubstituted oxazole derivatives. Moreover, the one-pot methodology features a metal-free strategy, readily available reagents, shorter times, good yields, and mild reaction conditions.

Zinc-catalyzed transamidation and esterification of N-benzoyl cytosine via C-N bond cleavage.

We have utilized N-benzoyl cytosine for efficient transamidation and esterification via catalytic C-N bond cleavage. The one-pot strategy involves the reaction of secondary amide with various aliphatic or aromatic amines and alcohols in the presence of zinc triflate and DTBP, affording diverse amides and esters in excellent yields.

Brønsted acidic ionic liquid-catalyzed tandem reaction: an efficient and sustainable approach towards the regioselective synthesis and molecular docking studies of 4-hydroxycoumarin-substituted indoles bearing lower E-factors.

1-Butane sulfonic acid-3-methylimidazolium tosylate, [BSMIM]OTs, is a remarkable catalyst for the cascade synthesis of coumarin-functionalized indole derivatives via a tandem cyclization reaction of aniline and phenylglyoxal monohydrate. This reaction possibly proceeds through imine formation/nucleophilic addition/cyclization. In addition, this method shows lower E-factors. A clean reaction, easily accessible reactants, metal-free and environmentally friendly reaction conditions, and reusability of the catalyst are the notable advantages of this procedure. In addition, molecular docking studies show the theoretical possibility of binding these types of synthesized compounds to key proteins in tumorigenesis.

Recent Advances in the Practical Synthesis of C1 Deuterated Aromatic Aldehydes Enabled by Catalysis and Beyond.

C1 -selective deuteration of aromatic aldehydes is of great importance for isotopic labeling and for improving the characteristics of drug molecules. Due to the recent increase in the use of deuterated pharmacological drugs, there is a pressing need for synthetic procedures that are efficient to produce deuterated aromatic aldehyde analouges. Deuterium labeling approaches are typically used as an effective tool for researching pharmaceutical absorption, distribution, metabolism, and excretion (ADME). Furthermore, deuterium-labeled pharmaceuticals are intended to increase therapeutic effectiveness and reduce side effects by extending the half-life of drug response. In the last few years, several catalytic or non-catalytic methods have been developed to synthesize deuterated aromatic aldehydes. In this concern, we offer a brief overview of the various synthetic strategies and practical methods for the formyl-selective deuterium labeling of aromatic aldehydes using different deuterium sources.

Iodine-TBHP mediated efficient synthesis of α-ketoamides from vinyl azides and amines under mild conditions.

A convenient and practical synthetic approach for α-ketoamides has been developed under mild conditions. The facile synthesis of α-ketoamides has been accomplished using aryl vinyl azides and secondary amines at room temperature. The inexpensive and readily available iodine and TBHP easily promoted the oxidative amidation process to afford diketoamide derivatives in high yields. This method involves the synthesis of ketoamide compounds via sequential C-O and C-N bond formation. Moreover, metal-free and aerobic conditions and wide substrate scope are the notable advantages of this protocol.

A new tandem synthesis of bis(ß,ß'-dialkoxy carbonyl) compounds by oxidative cleavage of aziridines under metal-free conditions.

An efficient and new approach has been developed to synthesize bis(ß,ß'-dialkoxy carbonyl) derivatives through the reaction between N-tosylaziridines and malonate esters under ambient air using tBuOK in DMSO solvent. A plausible reaction pathway has been predicted. Control experiments suggested that the reactions proceed through the formation of α-aminoketones. This reaction offers a broad substrate scope, metal-free synthesis, excellent regioselectivity, easily accessible reactants, and simple operation. A gram-scale synthesis demonstrates the potential applications of the present method.

In situ synthesis of CuO nanoparticles over functionalized mesoporous silica and their application in catalytic syntheses of symmetrical diselenides.

A versatile and novel catalyst, CuO nanoparticles immobilized over functionalized mesoporous silica (nCuO-FMS), has been synthesized over an organically modified mesoporous silica framework following a facile synthetic route. The surface of the silica support (SBA-15) is first grafted with the 3-aminopropyl silane group and then further functionalized with tris(4-formylphenyl)amine. The reaction is performed in such a way that a few -CHO groups remain free for further functionalization. Finally, the CuO nanoparticles immobilized on mesoporous silica are obtained by a one pot reaction between the functionalized silica, 2-aminophenol and CuCl2. The product obtained has been used as a catalyst for the syntheses of symmetrical diselenides in the presence of KOH as the base and dimethyl sulphoxide (DMSO) as the solvent. The materials have been characterized thoroughly by X-ray powder diffraction, nitrogen adsorption-desorption studies, transmission electron microscopy, thermal analysis and different spectroscopic techniques. The Cu content of the sample has been determined by atomic absorption spectrophotometry (AAS). The products of the catalytic studies have been identified and estimated by NMR spectroscopy. Almost 78% isolated yield could be achieved at 363 K within 3 hours of the reaction and the catalyst, nCuO-FMS, can be recycled at least up to five catalytic cycles.

Mild, Efficient, and Metal-Free Radical 1,2-Dithiocyanation of Alkynes and Alkenes at Room Temperature.

A transition metal-free process has been reported for 1,2-dithiocyanation of alkynes in the presence of sodium persulfate and potassium thiocyanate reagent combination in a short reaction time under ambient air. Styrene derivatives are equally applicable under the same reaction conditions. Monothiocyanated vinyl derivatives were also synthesized from 2-ethynylpyridine and dimethyl acetylene dicarboxylate. The reaction proceeds by the radical/polar pathway as evidenced from our experiments and literature. After removal of the solvent from the reaction mixture by evaporation, the crude product was purified without conventional workup.