Rapid access to 3-aminoindazoles from nitriles with hydrazines: a strategy to overcome the basicity barrier imparted by hydrazines

Practical Synthesis of 7-Bromo-4-chloro-1H-indazol-3-amine: An Important Intermediate to Lenacapavir

7-Bromo-4-chloro-1H-indazol-3-amine is a heterocyclic fragment used in the synthesis of Lenacapavir, a potent capsid inhibitor for the treatment of HIV-1 infections. In this manuscript, we describe a new approach to synthesizing 7-bromo-4-chloro-1H-indazol-3-amine from inexpensive 2,6-dichlorobenzonitrile. This synthetic method utilizes a two-step sequence including regioselective bromination and heterocycle formation with hydrazine to give the desired product in an overall isolated yield of 38-45%. The new protocol has been successfully demonstrated on hundred-gram scales without the need for column chromatography purification. This new synthesis provides a potential economical route to the large-scale production of this heterocyclic fragment of Lenacapavir.

Platform for the Immobilizing of Ultrasmall Pd Clusters for Carbonylation: In Situ Self-Templating Fabrication of ZIF-8 on ZnO

Incorporating metal clusters into the confined cavities of metal-organic frameworks (MOFs) to form MOF-supported catalysts has attracted considerable research interest with regard to carbonylation reactions. Herein, a self-templating method is used to prepare the zinc oxide (ZnO)-supported core-shell catalyst ZnO@Pd/ZIF-8. This facile strategy controls the growth of metal sources on the ZIF-8 shell layer and avoids the metal diffusion or aggregation problems of the conventional synthesis method. The characteristics of the catalysts show that the palladium (Pd) clusters are highly dispersed with an average particle size of ≈1.2 nm, making them excellent candidates as a catalyst for carbonylation under mild conditions. The optimal catalyst (1.25-ZnO@Pd/ZIF-8) exhibits excellent activity in synthesizing α, β-alkynyl ketones under 1 atm of carbon monooxide (CO), and the conversion rate of 1, 3-diphenylprop-2-yn-1-one is 3.09 and 3.87 times more than those of Pd/ZIF-8 and Pd2+, respectively, for the first 2 h. Moreover, the 1.25-ZnO@Pd/ZIF-8 is recyclable, showing negligible metal leaching, and, under the conditions used in this investigation, can be reused at least five times without considerable loss in its catalytic efficiency. This protocol can also be applied with other nucleophile reagents to synthesize esters, amides, and acid products.

Construction of Trisubstituted Hydrazones via Base-Mediated Cascade Condensation N-Alkylation

A practical base-promoted tandem condensation N-alkylation reaction for the formation of trisubstituted hydrazones has been developed employing aldehydes and hydrazines with alkyl halides. Crucially, this reaction successfully overcomes chemoselectivity problems, allowing for the reaction of multiple components in a one-pot manner. Halo- and heterofunctional groups, as well as free hydroxyl and amino groups, are tolerated in this transformation to produce a wide range of trisubstituted hydrazones in good to excellent yields.

Cascade Synthesis of Kinase-Privileged 3-Aminoindazoles via Intramolecular N-N Bond Formation

3-Aminoindazoles are privileged scaffolds for bioactive drug-like molecules. In this study, a microwave-assisted cascade reaction for the synthesis of N-1 substituted 3-aminoindazoles with yields up to 81% has been developed. Starting from 3-(2-bromoaryl)-1,2,4-oxadiazol-5(4H)-ones, the reaction exhibits a broad substrate scope including anilines, aliphatic amines, and sulfonamides and bypasses selectivity issues between N-1 and 3-amino group. Furthermore, the Differential Scanning Fluorimetry screen of a kinase panel demonstrated the value of targeting N-1 substituted 3-aminoindazoles as kinase-biased fragments.

Formamidation of a wide range of substituted and functionalized amines with CO and a base

We have developed a base mediated formamidation of amines with CO under mild conditions, which allows for the synthesis of a wide range of aromatic and aliphatic formamides in high yields and gram amounts in the absence of a transition metal.

A microporous anionic metal–organic framework for aqueous encapsulation and highly reversible sensitization of light-emitting Tb3+ ions

An anionic porous material can serve as both a host and an antenna for protecting and sensitizing extra-framework light-emitting Eu3+/Tb3+ ions. The Tb3+ uptake and release is a reversible process and the cationic Tb3+ can be gradually released.

A Type of MOF-Derived Porous Carbon with Low Cost as an Efficient Catalyst for Phenol Hydroxylation

Using MOF-5 as a template, the porous carbon (MDPC-600) possessing high specific surface area was obtained after carbonization and acid washing. After MDPC-600 was loaded with Cu ions, the catalyst Cu/MDPC-600 was acquired by heat treatment under nitrogen atmosphere. The catalyst was characterized by X-ray powder diffraction (XRD), N2 physical adsorption (BET), field emission electron microscope (SEM), energy spectrum, and transmission electron microscope (TEM). The results show that the Cu/MDPC-600 catalyst prepared by using MOF-5 as the template has a very high specific surface area, and Cu is uniformly supported on the carrier. The catalytic hydrogen peroxide oxidation reaction of phenol hydroxylation was investigated and exhibits better catalytic activity and stability in the phenol hydroxylation reaction. The catalytic effect was best when the reaction temperature was 80°C, the reaction time was 2 h, and the amount of catalyst was 0.05 g. The conversion rate of phenol was 47.6%; the yield and selectivity of catechol were 37.8% and 79.4%, respectively. The activity of the catalyst changes little after three cycles of use.

Recent developments on MOF-based platforms for antibacterial therapy

With increasing pathogenic bacterial infection that is occurring worldwide, antibacterial therapy has become an important research field. There is great antimicrobial potential in the nanomaterial-based metal-organic framework (MOF) platform because it is highly biocompatible, biodegradable, and nontoxic, and it is now widely used in the anticancer agent industry and in the production of medical products. This review summarizes the possible mechanisms of representative MOF-based nanomaterials, and recounts recent progress in the design and development of MOF-based antibacterial materials for the remedy of postoperative infection. The existing shortcomings and future perspectives of the rapidly growing field of antimicrobial therapy addressing patient quality of life issues are also briefly discussed. Because of their wide applicability, further studies on the use of different MOF antimicrobial therapies will be of great interest.

A practical base mediated synthesis of 1,2,4-triazoles enabled by a deamination annulation strategy

A rapid and efficient base mediated synthesis of 1,3,5-trisubstituted 1,2,4-triazoles has been developed using the annulation of nitriles with hydrazines, which can be expanded to a wide range of triazoles in good to excellent yields. Ammonia gas is liberated during the reaction, and halo and hetero functional groups as well as free hydroxyl and amino groups are tolerated in this transformation. A variety of alkyl and aryl-substituted nitriles can be functionalized with aromatic and aliphatic hydrazines employing this procedure. This finding provides a practical and useful strategy for the synthesis of various ¹⁵N-labeled 1,2,4-triazole derivatives, and two types of mGlu5 receptor pharmaceuticals can be easily assembled in a one-pot manner.