BF·OEt-mediated transamidation of unprotected primary amides under solvent-free conditions.

A BF·OEt-mediated transamidation between unactivated amides and amines is reported, enabling access to diverse secondary and tertiary amides under transition-metal-free and solvent-free conditions. The operationally simple procedure provides a novel manifold for converting amide-amide bonds with excellent chemoselectivity. In particular, a series of amides including challenging thioamides enable direct transamidation to products with modest to excellent yields.

Proposal for the classification of sinomenine alkaloids.

The chemical structure of sinoacutine is formed by a phenanthrene nucleus and an ethylamine bridge. Because it has a similar parent structure to morphine, it is subdivided into morphinane. At present, all reports have pointed out that the basic skeleton of morphine alkaloids is salutaridine (the isomer of sinoacutine), which is generated by the phenol coupling reaction of (R)-reticuline.

-alkyl Dithiocarbamates Synthesis through Electrochemical Multicomponent Reaction of Thiols, Hydrogen Sulfide, and Isocyanides.

Dithiocarbamates synthesis is extremely important in plenty of biomedical and agrochemical applications, especially fungicide development, but remains a great challenge. In this work, we have successfully developed a multicomponent reaction protocol to convert HS into -alkyl dithiocarbamates under constant current conditions. No additional oxidants nor additional catalysts are required, and due to mild conditions, the reactions display a broad substrate scope, including varieties of thiols or disulfides.

Ultrasound-assisted bromination of indazoles at the C3 position with dibromohydantoin.

Bromoaryl compounds have attracted great attention in organic chemistry, especially for the synthesis of pharmaceutical intermediates. Herein, we demonstrated a novel and efficient bromination protocol of indazoles C-H bond cleavage to give site-specific 3-bromide products that could be further employed as synthetic blocks to prepare drugs. The reaction used DBDMH as a bromine source, tolerated a wide range of indazoles, and finished in 30 min under mild, ultrasound-assisted conditions.

Electrosynthesis of -thiocarbamates with disulfides as a sulfur source.

An electrochemical oxidative synthesis of -thiocarbamates by a carbamothioation reaction a three-component coupling reaction (disulfide, water and isocyanide) is developed, which avoids the use of external oxidants and generates only hydrogen gas as the by-product. With NHI as the mediator and electrolyte, the desired -thiocarbamates were obtained in good yields in an undivided cell at room temperature.

Visible-Light Photosynthesis of CHF /CClF /CBrF -Substituted Ring-fused Quinazolinones in Dimethyl Carbonate.

With eco-friendly and sustainable CO -derived dimethyl carbonate as the sole solvent, the visible-light-induced cascade radical reactions have been established as a green and efficient tool for constructing various CHF /CClF /CBrF -substituted ring-fused quinazolinones.

Diethylaminosulfur Trifluoride: A Novel, Low-Cost, Stable Double Thiolation Reagent for Imidazo[1,2-α]pyridines.

We report a novel, inexpensive double thiolation reagent that sulfurizes a broad range of imidazo[1,2-α]pyridines under mild conditions. Importantly, diethylaminosulfur trifluoride, as a common nucleophilic fluorinating reagent, was utilized as a novel thiolation reagent.

Ultrasound-Assisted Iodination of Imidazo[1,2-α]pyridines Via C-H Functionalization Mediated by -Butyl Hydroperoxide.

A novel metal catalyst-free and environmentally friendly method for the regioselective iodination of imidazo[1,2-α]pyridines at their C3 position is disclosed, which has a wide substrate scope and could be sustainable. This reaction proceeds through ultrasound acceleration in the presence of a green alcohol solvent. Compared with a conventional heating system, the reaction efficiency and the rate are significantly improved and the iodine atom economy is maximized using ultrasound techniques.

Photoinduced efficient synthesis of cyanoalkylsulfonylated oxindoles sulfur dioxide insertion.

A visible-light-promoted radical cascade reaction of -arylacrylamide and cyclobutanone oxime esters with sulfur dioxide insertion is established. Mainly through the exploration of the visible light wavelength, it is found that the light source has a certain influence on the formation of cyanoalkylsulfonylated oxindoles, furnishing a range of sulfones in good to excellent yields. This protocol presents good functional group compatibility and does not require transition metals, photosensitizers, external bases, or oxidants.

Electrochemically promoted oxidative α-cyanation of tertiary and secondary amines using cheap AIBN.

The electrochemical α-cyanation of tertiary and secondary amines has been developed by using a cheap cyanide reagent, azobisisobutyronitrile (AIBN). The CN radical, generated through -BuNBr-meidated electrochemical oxidation, participates in a novel α-cyanation reaction under exogenous oxidant-free conditions.

Copper(i)-catalyzed intermolecular cyanoarylation of alkenes: convenient access to α-alkylated arylacetonitriles.

A novel Cu(i)-catalyzed intermolecular cyanoarylation of alkenes with diaryliodonium salts as a radical arylating reagent and tetra-butylammonium cyanide as an electrophilic cyanating reagent was established. A broad range of α-alkylated arylacetonitriles were efficiently constructed in good to excellent yields under base- and oxidant-free and mild conditions.

Electrochemical Synthesis of α-Ketoamides under Catalyst-, Oxidant-, and Electrolyte-Free Conditions.

A catalyst-, oxidant-, electrolyte-free method for the preparation of α-ketoamides through the direct electrochemical amidation of α-ketoaldehydes and amines with innocuous hydrogen as the sole byproduct at ambient temperature was developed. The present reaction features clean and mild conditions, excellent functional-group tolerance, and high atom economy and scalability, enabling facile applications in pharmaceutical chemistry.

Ultrasound accelerated synthesis of O-alkylated hydroximides under solvent- and metal-free conditions.

A novel, sustainable, environmentally friendly, high substrate scope, efficient, solvent-free and metal catalyst-free method for the cross-dehydrogenative coupling (CDC) reaction between N-hydroxyphthalimide (NHPI) and benzyl/ether compounds is described. This coupling reaction proceeds through ultrasound acceleration. Compared to conventional heating conditions, the use of ultrasound techniques not only improves the reaction efficiency and enhances the reaction rate but also minimizes the side reactions.

[A Hydride Generation-Catalytic Resonance Rayleigh Scattering Method for Detection of Trace Arsenic].

Arsenic is a toxic metal element and the establishment of a highly sensitive and selective method for As has great significance to human health and environment protection. In sulfuric acid medium, As(Ⅲ) was reduced by NaBH4 to form AsH3 gas that was trapped by the Ce(Ⅳ)-I- catalytic absorption solution to cause Ce(Ⅳ) concentration decreased and As particle increased, which resulted in the resonance Rayleigh scattering (RRS) and fluorescence increased at 370 and 351 nm respectively. The increased RRS and fluorescence intensities were linear to As(Ⅲ) concentration in the range of 0.

[A Facile Nanogold Surface Plasmon Resonance Absorption Method for CO Tracing].

The detection of gas pollutants in atmosphere and indoor air is very important to human health and safety. Monoxide carbon (CO) is a common gas pollutant with high toxicity that mainly comes from the inadequacy oxidization of carbon such as oil, coal and petrol inadequacy combustion, auto-gas and some natural disasters whose limit value in air is lower than 6.0 mg·m-3 in the national standard.

[Determination of Trace Boron Based on Gold Nanorod Plasmonic Resonance Rayleigh Scattering Energy Transfer to the Coordinate].

B is a necessary trace element for human and animals, but the excess intake of B caused poison. Thus, it is very important to determination of B in foods and water. The target of this study is development of a new, sensitive and selective resonance Rayleigh scattering energy transfer (RRS-ET) for the determination of B.

[Fluorescence Determination of Trace Se with the Hydride-K13-Rhodamine 6G System].

Se is a necessary trace element for human and animals, but the excess intake of Se caused poison. Thus, it is very important to determination of Se in foods and water. The target of this study is development of a new, sensitive and selective hydride generation-molecular fluorescence method for the determination of Se.

[Resonance Rayleigh scattering determination of trace tobramycin using aptamer-modified nanogold as probe ].

Nanogold (NG) was prepared using NaBH4 reduction of HAuCl4. The NG was modified by the tobramycin-aptamer to obtain a stable Apt-NG probe for tobramycin. The three aptamers containing 15, 21 and 27 bases were examined, and results showed that the aptamer with 21 bases was best and was chosen for use.

[Resonance Rayleigh scattering determination of trace ozone based on the cationic surfactant association particles].

In the presence of pH 4.0 HAC-NaAC buffer solution, using H3BO3-KI (BKI) as absorption solution, O3 oxidized KI to produce I2, and it reacted with excess I- to form I3- that combined with the cationic surfactant (CS) such as cetylpyridinium chloride (CPCl), tetradecyl pyridinium bromide (TPB), cetyl trimethyl ammonium bromide (CTMAB), and tetradecyl dimethylbenzyl ammonium chloride (TDMAC) to produce stable (CS-I3)n association particles, which exhibited a strong resonance Rayleigh scattering (RRS) peak at 470 nm. Under the chosen conditions, as the concentration of O3 (C) increased, the concentration of I3- increased, and the RRS intensity at 470 nm (1470 nm) increased due to more association particles forming.

[Resonance scattering detection of trace Hg2+ using herring sperm DNA modified nanogold].

In pH 7.0 tris-HCl buffer solutions and in the presence of 0.017 mol x L(-1) NaCl, herring sperm DNA was combined with gold nanoparticles in size of 10 nm to form stable complex, and the NaCl did not cause the aggregation of the gold nanoparticles.