ABSTRACT In this study, we report the iron‐catalyzed thiocyanation of heterocycles and aromatics using NH 3 ·H 2 O and CS 2 as the SCN source with (NH 4 ) 2 S 2 O 8 as an oxidant at room temperature. A string of heterocycles and aromatics, including indoles, pyrroles, anilines, pyrazols, and anisoles, are readily accommodated under environmentally benign conditions. The protocol provides access to various thiocyanated products bearing electron‐deficient/‐rich substituents at different positions in moderate to excellent yields. Mechanistic studies reveal the reaction probably proceeds via a radical process.
ABSTRACT Hetero)aryl boronic acids/esters are extremely useful synthetic building blocks, serving as starting materials or key intermediates in preparation of many useful compounds. Halogenation of (hetero)aryl boronic acids/esters is a frequently used method to introduce halogens, particularly for selective late‐stage radiohalogenation of drug molecules/leads. Diverse products can be obtained under different conditions. Therefore, the chemo‐ and regioselectivities are worthy attention. In this review, we summarize recent developments in the halogenation of (hetero)aryl boronic acids, including transition metal (TM)‐mediated/catalyzed aromatic substitution (S Ar ) halogenation of boronic acids/esters, ipso ‐halogenation, Ar‐H halogenation without modifying the boronic acid/ester moiety, and ipso ‐hydroxylation–halogenation. These approaches not only expand the accessible chemical space of (hetero)aryl boronic acids/esters, but also serve as useful tools in related research. Mechanism and perspective were also discussed.
ABSTRACT The fluorescent probes based on quinoline have garnered lots of attention due to their excellent photophysical properties. Normally the electron‐rich group connected at 7‐position of quinoline can form a better ICT effect in the conjugation which can enhance the photoluminescence properties of probes. To evaluate the role of these electron‐donating groups in probe performance, we designed, calculated and prepared three probes based on electron‐rich oxystyrylquinoline based on the results of theoretical calculations, featuring distinct substituents ( QTD , QTM , and QTH ) and investigated their structure–property relationships. Theoretical calculations show that QTM owns the strongest oscillator strength (0.6477) and the narrowest energy gap (2.8390 eV) among the three probes, which is consistent with its distinct ICT effect. Due to diminished electron‐donating strength, probe QTM emits in the red region (646 nm), while QTH and QTD showed blue shifted emissions at 618 and 554 nm, respectively. The studies of photophysical and sensing properties confirmed that stronger electron‐donation enhances ICT effect, resulting in longer emission wavelengths. QTM achieved the best property, with a detection limit of 32.32 µM, 180 min response time, and 79.32% quenching efficiency. An integrated computational/experimental approach was used to synergize theoretical calculation with experimental validation.
ABSTRACT Herein, an Et 3 N‐catalyzed [3 + 2] annulation reaction of 4‐oxo‐acrylamides with 2‐pyrones has been achieved under mild reaction conditions, providing straightforward access to a series of highly functionalized tetrahydropyrano[2,3‐b]pyrrole‐2,6‐dione derivatives in satisfactory results (52%–93% yields with >20:1 drs). In addition, this protocol features transition‐metal‐free conditions, excellent chemoselectivity, and ready applicability to further derivatization.
ABSTRACT Herein, we disclose a silver carbonate–mediated approach for desulfurative formation of C─N bonds. The reaction utilizes β‐acyl allylic sulfides in combination with readily available electron‐deficient N–H nucleophiles to access amide‐ and amine‐substituted α‐branched enones. A wide range of N─H nucleophiles is compatible with this transformation, including sulfonamides, phthalimides, as well as diverse (hetero)aromatic and aliphatic amines. Mechanistic studies suggest that the reaction proceeds via initial nucleophilic addition of the N─H nucleophile to the C═C bond of the β‐acyl allylic sulfide, followed by elimination of a methanethiolate anion. Notably, the reaction manifold can be extended beyond C─N bond formation to enable desulfurative C─O and C─C bond construction using N‐protected amino acids and carbon‐based nucleophiles.
ABSTRACT A TEMPO‐mediated electrochemical one‐pot three‐component strategy has been developed for the synthesis of 2,4‐disubstituted quinazolines from 2‐aminophenyl ketones, alcohols, and NH 4 OAc. This transition‐metal‐free protocol proceeds under mild conditions without the need for stoichiometric chemical oxidants, and exhibits broad substrate compatibility toward both alkyl and benzylic alcohols.
ABSTRACT Quinolinamines are one of the important class of compounds in terms of their biological activity and industrial applications. In this study, we have disclosed transition‐metal‐free synthesis of novel nitro‐substituted quinolinamines. This is the only report that allows the synthesis of quinolines having functionalities at benzene ring instead of pyridine ring. This transformation is compatible with aliphatic, aromatic as well as heteroaromatic substitution on alkynes. In addition, late‐stage modification of some biologically relevant molecules and natural products is disclosed. Furthermore, DFT study was performed to check potential application of the experimental synthesis. Geometrical properties, HOMO‐LUMO analysis, Global reactivity calculations, MEP maps and NLO properties were studied. In addition, docking was done by taking CDK2 protein (PDB ID: 3PXQ) to obtain a preliminary assessment of their potential biological interactions. The docking results showed significantly negative binding affinities reflecting the compounds strong binding with the receptor. Overall, the computational studies provide theoretical insights into the electronic, optical, and biological characteristics of the synthesized compounds and support future experimental evaluation of their potential applications.
ABSTRACT Owing to the structural importance and synthetic value of quinazoline and quinazolinone scaffolds in drug discovery, we herein report a novel NH 4 I‑involved oxidative annulation of readily available 2,1‑benzisoxazoles/isatoic anhydrides with benzylic alcohols for the selective synthesis of these heterocycles. In this three‑component transformation, ammonium iodide serves as both an economical nitrogen source and a co‑oxidant, avoiding the use of additional additives. This metal‑ and additive‑free protocol enables precise cleavage of C─O/N─O bonds with simultaneous formation of C─N bonds in a single operation, exhibiting excellent chemoselectivity, atom economy, and broad functional group tolerance. Additionally, the resulting quinazoline and quinazolinone derivatives are efficiently transformed into high‑value analogues of bioactive molecules, underscoring the synthetic utility of the method.
ABSTRACT A straightforward and efficient strategy for the synthesis of 3‐selanyl‐benzo[ b ]thiophenes is reported via the electrophilic cyclization of 2‐alkynylthioanisoles. This operationally simple reaction is conducted using Selecfluor as a mild, stable, and easy‐to‐handle oxidizing agent. The methodology is compatible with various functional groups, affording a range of benzo[ b ]thiophenes through the formation of new C─S and C─Se bonds in a single step, with moderate to good yields. Furthermore, the tolerance to disulfides and ditellurides demonstrates the flexibility of this new methodology in incorporating multifunctionalities into the synthesized benzochalcogenophenes.
ABSTRACT Azepino[3,2‐ b ]indoles are a class of pharmaceutically significant molecules containing an aza‐seven‐membered ring system. However, synthetic approaches to this scaffold remain limited and typically require multiple steps. Herein, we demonstrate the feasibility of synthesizing azepino[3,2‐ b] indoles via a Rh(III)‐catalyzed C─H activation followed by an annulation process using readily available ayrl oximes and maleimides. Moreover, this methodology features a short reaction time and broad functional group compatibility.
ABSTRACT The conversion of CO 2 into cyclic carbonates under mild conditions remained challenging due to the thermodynamic stability of CO 2 . Herein, a series of glutarimide‐based ionic liquids was developed for the cycloaddition of CO 2 to epoxides. Among them, [BZTMA][GLU] exhibited the highest activity, affording chloropropylene carbonate in 99.5% yield at 70°C within 7 h using only 2 mol% catalyst under 0.1 MPa CO 2 . Systematic variation of the cation ([BZTMA] + , [HDBU] + , [CH] + ), and anion ([GLU] – , [Im] – , [Pth] – ) revealed that catalytic performance was governed by a balance between CO 2 absorption capacity and cation‐anion interaction strength; excessively strong ion pairing counteracted the benefit of high CO 2 absorption. The catalyst was readily recovered and retained 95.9% yield after eight cycles. Substrate scope studies demonstrated that steric hindrance of both the epoxide and the anion critically influenced reactivity. This work established a clear structure‐activity relationship for the rational design of ionic liquid catalysts in CO 2 fixation.
ABSTRACT Efficient access to structurally important N‐heterocycles continues to be a major focus in synthetic chemistry owing to their broad relevance in medicinal and functional molecule synthesis. In this study, we report an efficient and practical metal‐free p‐TsOH·H 2 O‐promoted protocol for the synthesis of 2‐arylquinolones under batch and continuous‐flow conditions. The strategy provides two synthetic routes to 2‐arylquinolones; direct cyclization of readily accessible 2‐aminochalcones and a convenient one‐pot synthesis from 2‐aminoacetophenones and aldehydes, thereby avoiding the need to pre‐isolate the aminochalcone intermediates. The transformation proceeds effectively and accommodates a broad range of substrates bearing electron‐donating as well as electron‐withdrawing groups, delivering the desired 2‐arylquinolones in good to excellent yields. Importantly, translation of the methodology to continuous‐flow processing enabled rapid and selective access to both 2‐phenyl‐2,3‐dihydroquinolin‐4(1 H )‐ones and 2‐arylquinolones within minutes by adjusting the reaction atmosphere. The scalability and robustness of the protocol are demonstrated through gram‐scale experiments, highlighting its practical utility for synthetic applications.
ABSTRACT Ketones are important organic compounds. Electrosynthesis offers a mild and sustainable route for ketone synthesis. In this review, rather than summarizing reactions by substrate class or catalytic system, we adopt a mechanistically guided classification based on the origin of the carbonyl oxygen atom. Recent progress is accordingly divided into two categories: (1) transformations using non‐ketone oxygen sources (water, O 2 , CO, CO 2 , TEMPO, alcohols, acids, esters, and aldehydes). (2) functionalization of simple ketone‐containing molecules to access complex ketones. Organizing these methods according to oxygen source provides a unified mechanistic overview and practical guidance for reagent selection.
ABSTRACT We report a visible‐light photoredox‐catalyzed strategy for the divergent dual selenylation of inert C─H and N─H bonds. Using a single catalytic system with Ru(bpy) 3 Cl 2 ·6H 2 O and diselenides, arylamines and indoles are selectively converted to distinct N,C‐ or C,C‐disubstituted organoselenides, respectively. This mild, redox‐neutral protocol features broad substrate scope, excellent regioselectivity, and operational simplicity, providing a unified and step‐economical route to valuable diselenides. Mechanistic studies support a radical‐based pathway.
ABSTRACT Trametes sanguinea (syn. Pycnoporus sanguineus ), as an important white‐rot fungus, has gained significant attention in recent years due to its remarkable potential in both pharmacological and biodegradation applications. The past half‐decade has witnessed a dramatic proliferation of studies concerning the pharmacological properties of its extracts, wherein numerous bioactive metabolites have been elucidated and structurally defined. Mechanistic investigations have deepened our understanding of these bioactive substances, offering new avenues for therapeutic applications. With respect to biodegradation, T. sanguinea exhibits prominent capacity for degrading organic pollutants within heavy metal‐contaminated environments. This review summarizes the latest progress in the biological activity of T. sanguinea and its extracts, which can be divided into two categories: 1) Pharmacological activity; 2) degradation activity.
ABSTRACT A metal‐free, ortho‐selective C–H amination of phenols with azoles using TBN as the sole mediator is reported. The reaction provides direct access to N‐arylazoles, key scaffolds in pharmaceuticals and agrochemicals, under mild conditions (room temperature, inert atmosphere) without transition‐metal catalysts, prefunctionalized arenes, or external oxidants. A wide range of phenols and azoles (pyrazoles, imidazoles, triazoles, and tetrazoles) are compatible, affording ortho‐aminated products in good to excellent yields (up to 94%) with exceptional regiocontrol. Gram‐scale synthesis (2.08 g, 77% yield) and subsequent derivatizations demonstrate synthetic utility. Mechanistic studies support a radical pathway involving TBN‐generated nitrogen‐centered radicals.
ABSTRACT Five‐ and six‐membered saturated carbocyclic skeletons serve as core structural units in organic chemistry, medicinal chemistry, materials science, and life sciences. Herein, a metal‐free, mild, and efficient TMSOTf‐mediated alkene transformation method was developed, which enables the highly selective self‐dimerization cyclization of α ‐methylstyrene to efficiently afford multisubstituted indane derivatives. This system can be further extended to the tandem cyclization of polyenes, constructing complex polycyclic terpenoid skeletons with excellent diastereoselectivity (d.r. > 20:1).
ABSTRACT In this study, a transition metal‐free and thiol‐free method for constructing a series of highly functionalized thioesters has been developed, achieving moderate to good yields from benzothiazolium bromides, aroyl chlorides and H 2 O in a three‐component reaction, via an acid‐base‐promoted hydrolysis ring‐opening tandem reaction process. The present protocol features available starting materials, operational simplicity, and mild reaction conditions.
ABSTRACT Herein, we demonstrate the use of N─N bond cleavage and imine distal migration in photoinduced 1,2‐aminosulfonylation of alkene to synthesize β‐amino sulfonamides. The protocol features room temperature conditions, photocatalyst‐free, transition metal‐free synthesis, high yields, and simple operation.
ABSTRACT A Zn(II)‐catalyzed [3+2] annulation of NH 2 ‐enaminones with N‐tosylaziridines is described. Various NH 2 ‐enaminones, along with diversely substituted N‐tosylaziridines, underwent this transformation to deliver tetrasubstituted 2‐pyrrolines in 44%–98% yields under mild conditions. This protocol offers broad substrate scope, good functional group tolerance, and high regioselectivity. Additionally, the resulting tetrasubstituted 2‐pyrrolines could be oxidized to pyrrole (under air/TFA) or undergo tosyl migration (under KOH), highlighting their synthetic versatility.
