A base-promoted three-component coupling of carbon dioxide, amines, and N-tosylhydrazones has been developed. The reaction is suggested to proceed via a carbocation intermediate and constitutes an efficient and versatile approach for the synthesis of a wide range of organic carbamates. The advantages of this method include the use of readily available substrates, excellent functional group tolerance, wide substrate scope, and a facile work-up procedure.

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Metformin, traditionally regarded as a hypoglycemic drug, has been studied in other various fields including inflammation. The specific mechanism of metformin’s effect on immune cells remains unclear. Herein, it is verified that LPS-induced macrophages are characterized by enhanced endogenous fatty acid synthesis and the inhibition of fatty acid synthase (FASN) downregulates proinflammatory responses. We further show that metformin could suppress such elevation of FASN as well as proinflammatory activation in macrophages. In vivo, metformin treatment ameliorates dextran sulfate sodium (DSS)-induced colitis through impairing proinflammatory activation of colonic lamina propria mononuclear cells (LPMCs). The reduction of FASN by metformin hinders Akt palmitoylation, which further disturbs Akt membrane attachment and its phosphorylation. Metformin-mediated suppression of FASN/Akt pathway and its downstream MAPK signaling contributes to its anti-inflammatory role in macrophages. From the perspective of immunometabolism, our work points towards metformin utilization as an effective and potential intervention against macrophages-involved inflammatory diseases.

A phosgene- and metal-free synthesis of O-aryl carbamates is realized through a three-component coupling of carbon dioxide, amines and diaryliodonium salts. The reaction only requires a base as the promoter, providing access to a diverse array of O-aryl carbamates in moderate to high yields with excellent chemoselectivity.

We have successfully demonstrated that in the presence of N,N‐diisopropylethylamine, copper iodide could efficiently catalyze the coupling of internal propargylic alcohols with carbon dioxide to afford the corresponding α‐alkylidene cyclic carbonates in moderate to excellent yields. Moreover, we have developed a new and versatile protocol for the chemo‐ and stereoselective synthesis of a wide range of (E)‐α‐iodoalkylidene cyclic carbonates from carbon dioxide, propargylic alcohols and potassium iodide using copper salt as the promoter. The process is proposed to proceed through the trapping of the vinyl copper intermediate by in situ generated triiodide ion as electrophile.magnified image

An efficient and environmentally friendly method for the synthesis of organic carbamates from carbon dioxide has been developed via photolysis of α-aryldiazoesters under mild conditions in the absence of any...

A. General Remarks 1 H and 13 C NMR spectra were recorded using a Bruker DRX-400 spectrometer using CDCl 3 as solvent and TMS as an internal standard. The chemical shifts are referenced to signals at 7.26 and 77.0 ppm, respectively. IR spectra were obtained either as potassium bromide plates or as liquid films between two potassium bromide plates with a Bruker TENSOR 27 spectrometer. Melting points were determined with a Büchi Melting Point B-545 instrument. All substrates were commercially purchased and used without further purification. Mass spectra were recorded on a Thermo ISQ-II spectrometer at an ionization voltage of 70 eV equipped with a DB-WAX capillary column (internal diameter: 0.25 mm, length: 30 m). B. General procedure for the preparation of dithiocarbamates 3 A 25 mL dried Schlenk tube was charged with boronic acid 1 (0.5 mmol), amine 2 (2.5 mmol), CS 2 (1.0 mmol), Cu(OAc) 2 (1.0 mmol), K 2 CO 3 (1.5 mmol) and MeCN (4 mL) at room temperature. The reaction mixture was stirred at 60 °C for 10 h under air. After the reaction was completed, the mixture was cooled to room temperature and filtered through a plug of celite. The filtrate was then concentrated in vacuo to afford the crude product, which was then subjected to chromatography on silica gel with hexanes/EtOAc (20:1) to give the desired product 3.

A highly regio- and stereoselective C-C double bond formation reaction via Pd-catalyzed Heck-type cascade process with N-tosylhydrazones has been developed. Various N-tosylhydrazones derived from both ketones and aldehydes are found to be efficient substrates to provide di- and trisubstituted olefins with high regio- and stereoselectivity. Furthermore, this reaction has a good functional group tolerance and different benzofuran-, dihydrobenzofuran-, and indoline-containing alkene products were obtained with high selectivity.