Cp*Co(III)-catalyzed synthesis of isoquinolones via controlled annulation of primary arylamides with internal alkynes

In this study, we present the first cobalt(III)-catalyzed direct synthesis of isoquinolones from readily available primary arylamides and internal alkynes through a controlled oxidative C-H/N-H annulation reaction. This innovative protocol eliminates the need for expensive transition metal salts and external auxiliaries, producing the desired mono-annulated product exclusively while accommodating a wide range of substrates. Preliminary mechanistic studies highlight the critical role of copper oxide in facilitating the transformation. Additionally, peripheral modifications of the core isoquinolone rings have been performed to synthesize complex heterocyclic systems.

Rh(III)-Catalyzed Controlled Ortho-Amidation of Arylamides with Dioxazolones Using Weakly Coordinating Native Primary Amide as the Directing Group

Herein, we report a controlled introduction of an amide unit at the ortho-position of an electron-deficient arylamide system without affording any cyclized products using user-friendly dioxazolone as an amidating reagent in the presence of a Rh(III)-catalyst. This is the first report where native primary amide has been utilized as a weakly coordinating group for site-selective C-N bond formation reaction. The developed protocol works under external auxiliary-free conditions with a wide substrate scope.

Synthesis and characterization of nanocatalyst Cu2+/mesoporous carbon for amidation reactions of alcohols

In this research, mesoporous carbon (MC) with high efficiency (0.65 g yield from 1.0 g MCM-41 and 1.25 g sucrose) was successfully prepared by adding carbon precursor (sucrose) in a single step with ultrasonic waves, which reduces time and energy cost. Then, the Cu²⁺/Mesoporous carbon nanocatalyst (Cu²⁺/MC) was synthesized by adding Cu(NO₃)₂ in a single step and applied as a catalyst in amidation reactions of alcohols. Also, Cu²⁺/MC was characterized using different spectroscopic methods and techniques, including Fourier transform infrared spectroscopy (FT-IR), Field Emission Scanning Electron Microscopy (FE-SEM), N₂ adsorption analysis (BET), X-ray diffraction analysis (XRD), Energy Dispersive X-ray (EDX), and Thermogravimetric Analysis (TGA). Moreover, to show the catalytic merits of Cu²⁺/MC, various primary and secondary amines and ammonium salts were applied in the amidation of alcohols. Easy synthesis method, recyclability, excellent yields (80-93%), and simple work-up are some noticeable strengths of using Cu²⁺/MC as a catalyst in this reaction.

Au NPs fabricated on biguanidine-modified Zr-UiO-66 MOFs: a competent reusable heterogeneous nanocatalyst in the green synthesis of propargylamines

In this study, we utilized functionalized metal organic frameworks (MOFs) as a host matrix to embed gold (Au) nanoparticles.

Ru(II)-Catalyzed Controlled Cross-Dehydrogenative Coupling of Benzamides with Activated Olefins via Weakly Coordinating Primary Amides

Ru(II)-catalyzed regioselective ortho-alkenylation of primary benzamides with activated olefins has been realized over the competitive cyclized products. This reaction overall proceeds via a cross-dehydrogenative coupling (CDC) reaction using a simple and weakly coordinating primary amide group in the presence of an inexpensive Ru(II) salt and allows the controlled introduction of olefin motifs at the ortho-position of benzamides. The key to the success of this strategy depends on fine-tuning the reaction conditions. The developed protocol has demonstrated excellent regio/diastereoselectivity and a good functional group tolerance with wide substrate scope and obviates the requirement of external auxiliaries as well as the costly metal catalyst. Detailed mechanistic studies indicate the involvement of the base-assisted internal electrophilic-type substitution (BIES) step in the reaction mechanism.

Transition metal-free NaOH-catalyzed hydration of nitriles to primary amides in NH3·H2O-DMSO mixture

In this paper, we reported an efficient protocol for hydration of aryl(hetero) and alkyl nitriles toward primary amides with 0.1 equiv. NaOH in NH₃·H₂O-DMSO under mild conditions. Various substituted nitriles are smoothly converted to the corresponding amides with good to excellent isolated yields. Gram-scale reactions were also performed to produce the desired products in high yields. In addition, the excessive hydrolysis of the nitrile to form the corresponding carboxylic acid was also achieved with increasing the amount of NaOH and prolonging the reaction time.

The palladium(ii)-catalyzed regioselective ortho-C-H bromination/iodination of arylacetamides with in situ generated imidic acid as the directing group: mechanistic exploration

In the present study, we report the palladium(ii)-catalyzed regioselective ortho-C-H bromination/iodination of challenging arylacetamide derivatives using N-halosuccinimides as halogenating agents. Diverse arylacetamides underwent the regioselective ortho-bromination and iodination of aromatic C-H bonds in the presence of a reactive benzylic C(sp3)-H bond without installing any bulky auxiliaries via unfavorable six-membered metallacycles. Weak coordination, the use of ubiquitous primary amides for challenging C-H functionalization, the simple catalytic system and the wide substrate scope are the key features of this transformation. Further, the halogenated amide derivatives were transformed into a variety of valuable synthons. Detailed mechanistic studies revealed some interesting aspects concerning the reaction pathway. We present for the first time strong evidence for the formation of imidic acid (in situ) from primary amides under Brønsted acid conditions that eventually aids in the stabilization of palladacycles of amide derivatives and drives regioselective C-X bond formation.

Palladium-Catalyzed Regioselective C-H Alkenylation of Arylacetamides via Distal Weakly Coordinating Primary Amides as Directing Groups

Herein we disclose the efficient Pd(II)-catalyzed and regioselective ortho C-H alkenylation of arylacetamide derivatives, viz. weakly coordinating aliphatic primary amides. This protocol utilizes ubiquitous free primary amides as the directing group and circumvents two troublesome steps of installation and removal of an external auxiliary. This strategy directly enables the incorporation of a synthetically versatile olefin in the products in moderate to good yields with regio- and distereoselectivity. The alkenylated acetamides can be easily manipulated and further transformed into a variety of useful derivatives.

CuCl heterogenized on metformine-modified multi walled carbon nanotubes as a recyclable nanocatalyst for Ullmann-type C–O and C–N coupling reactions

Herein, a novel MWCNTs-Met/CuCl nanocatalyst synthesis method by metformine covalent grafting on the surface of carbon nanotubes and subsequent coordination with a CuCl catalyst is described.

Fe3O4/PEG-SO3H as a heterogeneous and magnetically-recyclable nanocatalyst for the oxidation of sulfides to sulfones or sulfoxides

We present below a sulfonated-polyethylene glycol-coated Fe₃O₄ nanocomposite (Fe₃O₄/PEG-SO₃H) as a greatly effective and ecological nanocatalyst for the selective oxidation of sulfides to sulfoxides or sulfones with brilliant yields under solvent-free conditions by employing 30% hydrogen peroxide as the oxidant.

Primary Amide Directed Regioselective ortho-C-H-Arylation of (Aryl)Acetamides

An efficient and regioselective palladium(II)-catalyzed primary acetamide assisted ortho arylation of arylacetamide has been discovered. This is the first report where functionalizable primary acetamide (-CH2CONH2) is used as a directing group for C(sp2)-H activation/cross-coupling reactions, circumventing the extra steps of installation and subsequent removal of the directing groups. The synthetic utility of this transformation is demonstrated through the scale-up synthesis. In addition, the primary acetamide can be manipulated into synthetically important derivatives such as nitriles and carboxylic acids.

Cytotoxic 1,3-Thiazole and 1,2,4-Thiadiazole Alkaloids from Penicillium oxalicum: Structural Elucidation and Total Synthesis

Two new thiazole and thiadiazole alkaloids, penicilliumthiamine A and B (2 and 3), were isolated from the culture broth of Penicillium oxalicum, a fungus found in Acrida cinerea. Their structures were elucidated mainly by spectroscopic analysis, total synthesis and X-ray crystallographic analysis. Biological evaluations indicated that compound 1, 3a and 3 exhibit potent cytotoxicity against different cancer cell lines through inhibiting the phosphorylation of AKT/PKB (Ser 473), one of important cancer drugs target.

Facile synthesis and investigation of 1,8-dioxooctahydroxanthene derivatives as corrosion inhibitors for mild steel in hydrochloric acid solution

For the first time, the corrosion inhibitive performance of some 1,8-dioxooctahydroxanthene derivatives is proposed.

Copper-catalyzed decarboxylative cross-coupling of cinnamic acids and ACCN via single electron transfer

A novel and convenient method for the synthesis of β,γ-unsaturated nitriles using ACCN (1,1′-azobis(cyclohexane-1-carbonitrile)) as a cyano source was described.