198341-20-7

Upstream product

• 63139-21-9 4-ethylphenylboronic acid 
• 140-88-5 ethyl acrylate 
• 4748-78-1 4-ethylbenzylaldehyde 
• 1099-45-2 ethyl (triphenylphosphoranylidene)acetate 
• 100-41-4 ethylbenzene 
• 25309-64-2 4-ethyl-1-iodobenzene 
• 1585-07-5 1-bromo-4-ethylbenzene 
• 105-36-2 ethyl bromoacetate 

Downstream Products

• 64740-36-9 3-(4-ethyl-phenyl)-propionic acid 
• 120680-98-0 4-ethylcinnamic acid 

Relevant academic research and scientific papers

Serendipitous synthetic entree to tetradehydro analogues of cobalamins

Tetradehydrocorrin macrocycles occupy a saturation level halfway between that of octadehydrocorrins and corrins (e.g., cyanocobalamin). While octadehydrocorrin chemistry is relatively well understood, few studies have been done on more reduced macrocycles owing to synthetic limitations. The reaction of a 2,3-dihydro-1,3,3-trimethyldipyrrin (Western half) bearing a 7-(4-iodophenyl) group and a 1-(dimethoxymethyl)-9-bromo-2,3-dihydro-3,3- dimethyldipyrrin (Eastern half) bearing a 7-p-tolyl group in the presence of Ga(OTf)3 afforded the corresponding B,D-tetradehydrocorrin (1) in 24% yield. Use of a Western half bearing a 7-(4-ethylphenyl) group afforded the B,D-tetradehydrocorrin (2) in 29% yield. Each tetradehydrocorrin bears a 1-methyl group at the A-D ring junction (and hence is enantiomeric), a geminal dimethyl group in each pyrroline ring, and distinct substituents at the 7- and 17-positions; characterization included 1H and 13C NMR spectroscopies, absorption spectroscopy, mass spectrometry, and X-ray crystallography (2 only). Treatment of 1 or 2 with CoCl2 afforded the cobalt chelate as a mixture of stereoisomers containing an apical methoxide or hydroxide ligand. The cobalt-tetradehydrocorrin was characterized by absorption spectroscopy, mass spectrometry, infrared spectroscopy and electrochemistry. The cobalt chelate was smoothly titrated with THF, pyridine, and KCN or Bu 4NCN. While the assignment of the oxidation state of the cobalt remains provisional, the use of natural abundance versus isotopically substituted solvents or titrants (CD3OD, K13CN) enabled clear identification of the apical ligands. The facile access to stable, synthetically tailored B,D-tetradehydrocorrins should open the door to fundamental studies of simple surrogates of cyanocobalamin.

Threonine stabilizer-controlled well-dispersed small palladium nanoparticles on modified magnetic nanocatalyst for Heck cross-coupling process in water

We report the synthesis of magnetically separable Fe3O4@Silica-Threonine-Pd0 magnetic nanoparticles with a core–shell structure. After synthesis of Fe3O4@Silica, threonine as an efficient stabilizer/ligand was bonded to the surface of Fe3O4@Silica. Then, palladium nanoparticles were generated on the threonine-modified catalyst. The threonine stabilizer helps to generate palladium nanoparticles of small size (less than 4?nm) with high dispersity and uniformity. Magnetically separable Fe3O4@Silica-Threonine-Pd0 nanocatalyst was fully characterized using various techniques. This nanocatalyst efficiently catalysed the Heck cross-coupling reaction of a variety of substrates in water medium as a green, safe and inexpensive solvent at 80°C. The Fe3O4@Silica-Threonine-Pd0 catalyst was used for at least eight successful consecutive runs with palladium leaching of only 0.05%.

Ligand-accelerated non-directed C-H functionalization of arenes

The directed activation of carbon-hydrogen bonds (C-H) is important in the development of synthetically useful reactions, owing to the proximity-induced reactivity and selectivity that is enabled by coordinating functional groups. Palladium-catalysed non-directed C-H activation could potentially enable further useful reactions, because it can reach more distant sites and be applied to substrates that do not contain appropriate directing groups; however, its development has faced substantial challenges associated with the lack of sufficiently active palladium catalysts. Currently used palladium catalysts are reactive only with electron-rich arenes, unless an excess of arene is used, which limits synthetic applications. Here we report a 2-pyridone ligand that binds to palladium and accelerates non-directed C-H functionalization with arene as the limiting reagent. This protocol is compatible with a broad range of aromatic substrates and we demonstrate direct functionalization of advanced synthetic intermediates, drug molecules and natural products that cannot be used in excessive quantities. We also developed C-H olefination and carboxylation protocols, demonstrating the applicability of our methodology to other transformations. The site selectivity in these transformations is governed by a combination of steric and electronic effects, with the pyridone ligand enhancing the influence of sterics on the selectivity, thus providing complementary selectivity to directed C-H functionalization.

Imidazolyl-Functionalized Ordered Mesoporous Polymer from Nanocasting as an Effective Support for Highly Dispersed Palladium Nanoparticles in the Heck Reaction

New imidazolyl-functionalized ordered mesoporous cross-linked polymers were prepared by the copolymerization of the ionic liquid 3-benzyl-1-vinyl-1H-imidazolium bromide with divinylbenzene as the cross-linker and azobisisobutyronitrile as the radical initiator in the presence of O-silylated SBA-15 as the hard template. The materials were characterized by N2 adsorption–desorption analysis, TEM, thermogravimetric analysis, elemental analysis, and FTIR spectroscopy. The material, which benefits from the use of entrapped ionic liquid in the prepared polymer matrix in combination with its ordered mesoporous structure, is an excellent environment for the stabilization of highly dispersed Pd nanoparticles to result in a recyclable catalyst system with a significant activity in the Heck coupling reaction of aryl halides. The presence of well-distributed imidazolium functionalities in the polymeric framework might be responsible for the relatively uniform and nearly atomic scale distribution of Pd nanoparticles throughout the mesoporous structure and the prevention of Pd agglomeration during the reaction, which results in high durability, high stability, and good recycling characteristics of the catalyst. Although our catalyst system operates in a homogeneous pathway, it is also very stable and recyclable.

Improved synthesis of natural ester sintenin and its analogues via Wittig reaction

The synthesis of a cytotoxic natural ester sintenin (7a) and twenty eight of its analogues including nitrogen-containing heterocyclic indole moiety (7b-7t), saturated (10a-10d) and unsaturated (10e-10h) amides were carried out by convenient route via one-pot Wittig reaction in aqueous medium with improved yield. A systematic structure activity relationship of sintenin ester was designed by chemically modified derivatives in order to get better cytotoxicity.

Synthesis, characterization of palladium hydroxysalen complex and its application in the coupling reaction of arylboronic acids: Mizoroki-Heck type reaction and decarboxylative couplings

(Salen-OH)Pd (1, salen-OHN,N′-bis(3,5-di-hydroxysalicylidene)- ethylenediamine) was prepared by a simple one step reaction and fully characterized by 1H and 13C NMR, IR spectroscopy, and X-ray crystallography. This palladium complex showed good activities as a catalyst in the Mizoroki-Heck-type reaction and the decarboxylative coupling reaction. In the Mizoroki-Heck type reaction, arylboronic acids and alkenes were reacted at 90°C for 3 h in the presence of 2.0 mol% of the palladium complex 1 and AgOAc to give the desired coupled product in good yields. In the decarboxylative coupling reactions, the desired coupled products were obtained in good yields when 0.5 mol% of the palladium complex was employed at room temperature.