ABSTRACT
A catalyst, based on a biarylphosphine ligand, for the Pd-catalyzed cross-coupling reactions of amides and aryl mesylates is described. This system allows an array of aryl and heteroaryl mesylates to be transformed into the corresponding N-aryl amides in moderate to excellent yields.
Subject(s)
Amides/chemistry , Amides/chemical synthesis , Mesylates/chemistry , Organometallic Compounds/chemistry , Palladium/chemistry , Catalysis , Ligands , Molecular Structure , StereoisomerismABSTRACT
A highly regioselective hydroamination of unsymmetrical electron-poor and electron-rich alkynes with anilines catalyzed by Au(I) under mild conditions is reported. In addition, applications toward indole syntheses are presented including an example of a one-pot synthesis from a nonfunctionalized aniline.
Subject(s)
Alkynes/chemistry , Aniline Compounds/chemistry , Gold/chemistry , Propionates/chemistry , Catalysis , Combinatorial Chemistry Techniques , Cyclization , Molecular Structure , StereoisomerismABSTRACT
A Pd-catalyzed, one-pot, two-step synthesis of 2-amidoindoles from ynamides and o-iodoanilines is reported. A key highlight of this sequence is that after the Sonogashira reaction, intramolecular cyclization to the indole occurs spontaneously without activation of the alkyne.
Subject(s)
Alkynes/chemistry , Amides/chemistry , Indoles/chemical synthesis , Aniline Compounds/chemistry , Catalysis , Indoles/chemistry , Ligands , Molecular Structure , Palladium/chemistry , StereoisomerismABSTRACT
A catalyst based on a new biarylphosphine ligand (3) for the Pd-catalyzed cross-coupling reactions of amides and aryl chlorides is described. This system shows the highest turnover frequencies reported to date for these reactions, especially for aryl chloride substrates bearing an ortho substituent. An array of amides and aryl chlorides were successfully reacted in good to excellent yields.
ABSTRACT
The yields of ynamides using Hsung's second generation protocol depend substantially on the quality of K(3)PO(4). Samples of K(3)PO(4) from different suppliers were investigated by various techniques, revealing that the use of pure and anhydrous K(3)PO(4) provides higher ynamide yields in comparison to samples contaminated with hydrates (K(3)PO(4) x 1.5 H(2)O and K(3)PO(4) x 7 H(2)O). With high quality K(3)PO(4), a number of ynamides were synthesized in yields of 52-91%. In addition, we report that ynamides can undergo regioselective hydroamination with carbamates.
Subject(s)
Alkynes/chemistry , Amides/chemistry , Chemistry, Organic/methods , Phosphates/chemistry , Potassium Compounds/chemistry , Carbamates/chemistry , Catalysis , Copper/chemistry , Models, Chemical , Potassium/chemistry , Spectrophotometry, Infrared/methods , Thermogravimetry/methods , Time FactorsABSTRACT
Four different conductive supports are analysed regarding their suitability for combined atomic force and scanning electrochemical microscopy (AFM-SECM) on biological membranes. Highly oriented pyrolytic graphite (HOPG), MoS(2), template stripped gold, and template stripped platinum are compared as supports for high resolution imaging of reconstituted membrane proteins or native membranes, and as electrodes for transferring electrons from or to a redox molecule. We demonstrate that high resolution topographs of the bacterial outer membrane protein F can be recorded by contact mode AFM on all four supports. Electrochemical feedback experiments with conductive cantilevers that feature nanometre-scale electrodes showed fast re-oxidation of the redox couple Ru(NH(3))(6)(3+/2+) with the two metal supports after prolonged immersion in electrolyte. In contrast, the re-oxidation rates decayed quickly to unpractical levels with HOPG or MoS(2) under physiological conditions. On HOPG we observed heterogeneity in the re-oxidation rate of the redox molecules with higher feedback currents at step edges. The latter results demonstrate the capability of conductive cantilevers with small electrodes to measure minor variations in an SECM signal and to relate them to nanometre-scale features in a simultaneously recorded AFM topography. Rapid decay of re-oxidation rate and surface heterogeneity make HOPG or MoS(2) less attractive for combined AFM-SECM experiments on biological membranes than template stripped gold or platinum supports.
