PTSA-catalyzed one-pot synthesis of quinoxalines using DMSO as the oxidant

<p>An efficient p-toluene sulfonic acid–catalyzed, one-pot, two-step oxidative system for cyclization of o-diaminobenzene with 1,2-diaryl-2-hydroxyethanone to quinoxalines was described. A nontoxic, readily available oxidant, dimethylsulfoxide (DMSO), was applied in this process. A broad range of substrates was applied to this method, and target compounds were obtained with good yields.</p

Cu-Catalyzed Three-Component Coupling of Aryne, Alkyne, and Benzenesulfonothioate: Modular Synthesis of <i>o</i>‑Alkynyl Arylsulfides

A copper-catalyzed three-component coupling reaction of in situ formed arynes, terminal alkynes, and benzenesulfonothioates is described. This reaction provides an efficient modular synthesis of <i>o</i>-alkynyl arylsulfides from easily available starting materials. This process involves one C–S bond and one C–C bond formation in one pot

Cascade One-Pot Method To Synthesize Isoquinolin-1(2<i>H</i>)‑ones with α‑Bromo Ketones and Benzamides via Pd-catalyzed C–H Activation

A cross-coupling strategy of palladium-catalyzed <i>ortho</i>-C–H bond activation and intramolecular addition of N–C annulation to synthesize isoquinolin-1­(2<i>H</i>)-ones has been developed. A wide range of α-bromo ketones with different substituents proceeded smoothly in this reaction, and varieties of isoquinolin-1­(2<i>H</i>)-one derivatives were obtained in moderate to good yields

One-Pot Synthesis of Pyrrolo­[1,2‑<i>a</i>]­quinoxaline Derivatives via a Copper-Catalyzed Aerobic Oxidative Domino Reaction

A copper-catalyzed process for the synthesis of pyrrolo­[1,2-<i>a</i>]­quinoxalines from readily available α-amino acids and 1-(2-halophenyl)-1<i>H</i>-pyrroles is described. Different functional groups were well tolerated to give the corresponding products

Cu(I)-Catalyzed Synthesis of Furan-Substituted Allenes by Use of Conjugated Ene-yne Ketones as Carbene Precursors

The synthesis of furan-substituted allenes using conjugated ene-yne ketones as carbene source has been developed. For this reaction, bases play vital roles in controlling the reaction pathways, allowing for access to two types of allene products through trapping of different electrophiles. Mechanistically, the catalytic procedure generated a Cu­(I) (2-furyl)­carbene intermediate, which is subsequently followed by a migratory insertion process to afford nucleophilic organocopper species. The organocopper species thus generated can be trapped by proton or allyl halide, affording tri- or tetrasubstituted allenes, respectively. The reaction, which is characterized by its mild reaction conditions and the utilization of cheap copper­(I) iodide as catalyst, allows for synthesis of a variety of furan-substituted allenes with a wide range of functional groups tolerance

Uniform and Persistent Jumping Detachment of Condensed Nanodroplets

Realizing jumping detachment of condensed droplets from solid surfaces at the smallest sizes possible is vital for applications such as antifogging/frosting and heat transfer. For instance, if droplets uniformly jump at sizes smaller than visible light wavelengths of 400–720 nm, antifogging issues could be resolved. In comparison, the smallest droplets experimentally observed so far to jump uniformly were around 16 μm in radius. Here, we show molecular dynamics (MD) simulations of persistent droplet jumping with a uniform radius down to only 3.6 nm on superhydrophobic thin-walled lattice (TWL) nanostructures integrated with superhydrophilic nanospots. The size cutoff is attributed to the preferential cross-lattice coalescence of island droplets. As an application, the MD results exhibit a 10× boost in the heat transfer coefficient (HTC), showing a −1 scaling law with the maximum droplet radius. We provide phase diagrams for jumping and wetting behaviors to guide the design of lattice structures with advanced antidew performance

Uniform and Persistent Jumping Detachment of Condensed Nanodroplets

Realizing jumping detachment of condensed droplets from solid surfaces at the smallest sizes possible is vital for applications such as antifogging/frosting and heat transfer. For instance, if droplets uniformly jump at sizes smaller than visible light wavelengths of 400–720 nm, antifogging issues could be resolved. In comparison, the smallest droplets experimentally observed so far to jump uniformly were around 16 μm in radius. Here, we show molecular dynamics (MD) simulations of persistent droplet jumping with a uniform radius down to only 3.6 nm on superhydrophobic thin-walled lattice (TWL) nanostructures integrated with superhydrophilic nanospots. The size cutoff is attributed to the preferential cross-lattice coalescence of island droplets. As an application, the MD results exhibit a 10× boost in the heat transfer coefficient (HTC), showing a −1 scaling law with the maximum droplet radius. We provide phase diagrams for jumping and wetting behaviors to guide the design of lattice structures with advanced antidew performance

Uniform and Persistent Jumping Detachment of Condensed Nanodroplets

Realizing jumping detachment of condensed droplets from solid surfaces at the smallest sizes possible is vital for applications such as antifogging/frosting and heat transfer. For instance, if droplets uniformly jump at sizes smaller than visible light wavelengths of 400–720 nm, antifogging issues could be resolved. In comparison, the smallest droplets experimentally observed so far to jump uniformly were around 16 μm in radius. Here, we show molecular dynamics (MD) simulations of persistent droplet jumping with a uniform radius down to only 3.6 nm on superhydrophobic thin-walled lattice (TWL) nanostructures integrated with superhydrophilic nanospots. The size cutoff is attributed to the preferential cross-lattice coalescence of island droplets. As an application, the MD results exhibit a 10× boost in the heat transfer coefficient (HTC), showing a −1 scaling law with the maximum droplet radius. We provide phase diagrams for jumping and wetting behaviors to guide the design of lattice structures with advanced antidew performance

Cu(I)-Catalyzed Cross-Coupling of Conjugated Ene-yne-ketones and Terminal Alkynes: Synthesis of Furan-Substituted Allenes

A new method for the synthesis of furan-substituted allenes via Cu­(I)-catalyzed coupling of conjugated ene-yne-ketones with terminal alkynes has been developed. A wide range of functional groups are tolerated, and the products are obtained in good to excellent yields under mild conditions. A copper carbene migratory insertion is proposed as the key step in this transformation with conjugated ene-yne-ketones as carbene precursors

Reactivity-Controlled Preparation of Ultralarge Graphene Oxide by Chemical Expansion of Graphite

The production of ultralarge graphene oxide (ULGO) is hindered by sluggish diffusion process of the oxidizing agents into graphite layers, as well as sheet fracture resulting from inhomogeneous oxidation. Previous methods rely on an excess amount of oxidants or multiple oxidation to overcome large diffusion resistance, but at the cost of ULGO yield and environmental risk. Here, we discover the chemical expansion of graphite (CEG) with high solvent-accessible surface areas can effectively boost mass diffusion and facilitate exhaustive oxidation at low oxidant dosage (2 wt equiv). The oxidizing reaction is therefore controlled by the chemical reactivity of graphite with oxidant rather than the diffusion of oxidant, which results in a ∼100% yield of ULGO nanosheets with an area-average size of 128 μm. The worm-like structure of CEG and its oxide provides a chance to recover excess sulfuric acid using a 100-mesh filter, where subsequent exfoliation to ULGO nanosheets is achieved by mild agitation or shaking in several minutes. The ULGO paper prepared by blade casting exhibits superior mechanical properties (Young’s modulus of 11.9 GPa and tensile strength of 110.8 MPa) and electrical conductivity (∼613 S/cm after HI reduction)