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A novel, multicomponent approach to 2-(imidazo[1,2-a]pyridin-3-yl)-N,N-dialkylacetamides (very important class of fused heterocyclic derivatives, known to act on central nervous system by enhancing the activity of the GABA) is reported. It is based on the carbonylation reaction of N-Boc-(prop-2-yn-1-yl)pyridin-2-amines carried out in the presence of secondary amines (2–3 equiv) under oxidative conditions, using oxygen (from air) as oxidant (4:1 CO-air, total pressure 20 atm) and PdI2/KI as the catalytic system (0.33–1 mol% of PdI2 and 0.5 equiv of KI) in MeCN as the solvent at 100 °C. The process leads to the target compounds in good to high yields (67–90%) through an ordered sequence of steps, occurring in situ under the reaction conditions: Boc-deprotection of the substrate is followed by PdI2/KI-catalyzed oxidative monoaminocarbonylation of the terminal triple bond (or vice versa) to give a 2-ynamide intermediate, which then undergoes intramolecular aza-Michael reaction and isomerization.

In the article mentioned in the title, the authors have tried to demonstrate that, in the previously reported Pd/iodide-catalyzed oxidative carbonylations of amines to give ureas, the role of iodide ligands was essentially to “etch” the stainless steel autoclaves where the process was performed, releasing in solution small amounts of iron salts. These latter iron species were, in their opinion, the real co-catalysts of the reaction, through the presumed formation of more active Pd/Fe bimetallic species. However, no solid experimental evidence corroborating this hypothesis has been given in the article, while all previous experimental evidences and literature data tend to exclude the involvement of iron co-catalysis in the Pd/iodide-promoted reactions.

An innovative hydrophilic and anti-fouling coating material for application in membrane technology for wastewater treatment has been developed by polymerization of a polymerizable bicontinuous microemulsion (PBM) and used for surface modification of a commercial flat polyethersulfone (PES) membrane. The novel nanostructured coating has been produced using acryloyloxyundecyltriethylammonium bromide (AUTEAB) as a co-polymerizable surfactant, obtained through a synthetic method characterized by a lower cost and a higher reproducibility compared to other known polymerizable surfactants. The novel composite membranes have been characterized and compared with the uncoated PES membranes. Coated membranes resulted in a smoother surface and a higher hydrophilicity with respect to the uncoated ones, and showed a particular nano-size channel-like morphology making them highly resistant to the fouling phenomenon. The covalent anchorage of the surfactant on the membrane surface ensured the embedment of the molecule in the polymeric matrix avoiding its leaching and also leading the coated membranes to have significant antimicrobial activity, which is very important for reducing the biofouling phenomenon.All these aspects make the tailored coating material an ideal and efficient coating for modifications of commercial membrane surfaces, to be used in membrane processes in wastewater treatment., European Union within the BioNexGen project EU-F17/project (CP-FP-246039-2)

A new extended viologen, 4,4′-(2,2′-bithiophene-5,5′-diyl)bis(1-decylpyridinium) triflimide (DTEV2+), has been synthesized and characterized at theoretical and experimental level. Electrochemical and spectroelectrochemical characterization show that this compound undergoes a two-electron reduction mechanism. Density functional computations give insights on the conformational properties of the different reduction species and allow the assignment of the absorption spectra. The agreement between calculated and experimental spectra is quite satisfactory.

A convenient, recyclable catalytic synthesis of benzofuran-2-acetic esters 2 by sequential Pd(0)-catalyzed deallylation—Pd(II)-catalyzed carbonylative heterocyclization of 1-(2-allyloxyphenyl)-2-yn-1-ols 1 in ionic liquids is presented. Reactions were typically carried out in BmimBF4 as the solvent at 100 °C and under 30 atm of CO, in the presence of catalytic amounts (1 mol %) of PdI2 in conjunction with KI (1 equiv), PPh3 (4 mol %), MeOH (28 equiv), and H2O (2 equiv). The solvent-catalyst system could be recycled several times without appreciable loss of catalytic activity.

The effect of CO 2 on the reaction of a terminal alkyne with CO and H 2 O in the presence of PdI 2 –KI was studied. With simple 1-alkynes such as alkyl- or arylacetylenes in the absence of added CO 2 a catalytic process takes place with formation of substituted furan-2(5 H )-ones 1 , deriving from a reductive carbonylation process. Oxidation of CO to CO 2 accounts for the stoichiometry of the reaction. The latter may occur through decarboxylation of a Pd–CO 2 H species with formation of a Pd–H species, which is in turn responsible for the reduction process. It has been found that working in the presence of added CO 2 the latter can also work as hydrogen acceptor, probably via its insertion into the Pd–H bond. In this way a catalytic synthesis of maleic anhydrides 2 , corresponding to an oxidative carbonylation process, can be obtained even in the absence of external oxidants. In contrast with simple 1-alkynes, the use of 2-methylbut-3-yn-2-ol in the absence of added CO 2 results in additive carbonylation with formation of teraconic anhydride 5 , formally deriving from the combination of oxidative dicarbonylation and reduction. No CO 2 effect is observed in this case, which rules out the intervention of Pd–H species in the catalytic cycle leading to 5 . As expected, however, carbon dioxide effect is felt by secondary products resulting from reductive carbonylation, their formation being curtailed by CO 2 addition to the reaction mixture.

A novel synthesis of 2-ynamides (3) by palladium-catalyzed oxidative aminocarbonylation of alk-1-ynes (1) is reported. Reactions are catalyzed by PdI2/KI and are carried out at 100°C in dioxane as the solvent in the presence of dialkylamines (2) as nucleophiles (amine/alk-1-yne molar ratio=1/1) using a 4/1 CO/air mixture (20 atm total pressure at 25°C).

A simple and economical synthesis of substituted furans and pyrroles, by ligand-free CuCl2-catalyzed heterocyclodehydration of readily available 3-yne-1,2-diols and N-Boc- or N-tosyl-1-amino-3-yn-2-ols, respectively, is presented. Reactions are carried out in MeOH at 80–100 °C for 1–24 h and afford the corresponding heterocyclic derivatives in 53–99% isolated yields.

A novel and convenient approach to furan-3-carboxylic esters 2 is presented, based on palladium-catalyzed direct oxidative carbonylation of readily available 3-yne-1,2-diols 1 . The process, corresponding to a sequential combination between a 5- endo - dig heterocyclodehydration step and an oxidative alkoxycarbonylation stage, is catalyzed by PdI 2 in conjunction with an excess of KI under relatively mild conditions (100 °C in ROH under 40 atm of a 4:1 mixture of CO-air).