15851-77-1Relevant academic research and scientific papers
Arylation of Terminal Alkynes by Aryl Iodides Catalyzed by a Parts-per-Million Loading of Palladium Acetate
Hamasaka, Go,Roy, David,Tazawa, Aya,Uozumi, Yasuhiro
, p. 11640 - 11646 (2019/12/02)
Arylation of terminal alkynes (16 varieties) by aryl iodides (28 varieties) was achieved with a mol ppm loading level of palladium catalyst, where a variety of functional groups including heteroarenes were tolerated. Thus, the arylations were carried out in the presence of palladium acetate at ppm loadings and potassium carbonate in ethanol at 80 °C to give the corresponding internal alkynes in good to excellent yields. Synthesis of 2-phenyl-3-(phenylalkynyl)benzofuran was achieved by iterative use of the alkyne arylation under mol ppm catalytic conditions. Reaction-rate analysis, transmission electron microscopic (TEM) examination of the reaction mixture, and mercury-amalgamation test were performed to gain insight into the active species of the highly active ppm catalytic species. TEM examination of the reaction mixture revealed that palladium nanoparticles were generated in situ under the reaction conditions, and their cluster size was variable during the catalytic reaction. A variation in size of palladium particles suggested that the composition-decomposition process of Pd aggregates should take place in situ via monomeric palladium(0) species and/or fine palladium(0) clusters, which might be real catalytic species in this reaction.
Synthesis, structure-activity relationships, and pharmacokinetic properties of dihydroorotate dehydrogenase inhibitors: 2-cyano-3-cyclopropyl- 3-hydroxy. N-[3'-methyl-4'-(trifluoromethyl)phenyl]propenamide and related compounds
Kuo, Elizabeth A.,Hambleton, Philip T.,Kay, David P.,Evans, Phillip L.,Matharu, Saroop S.,Little, Edward,McDowall, Neil,Jones, C. Beth,Hedgecock, Charles J. R.,Yea, Christopher M.,Chan, A. W. Edith,Hairsine, Peter W.,Ager, Ian R.,Tully, W. Roger,Williamson, Richard A.,Westwood, Robert
, p. 4608 - 4621 (2007/10/03)
The active metabolite (2) of the novel immunosuppressive agent leflunomide (1) has been shown to inhibit the enzyme dihydroorotate dehydrogenase (DHODH). This enzyme catalyzes the fourth step in de novo pyrimidine biosynthesis. A series of analogues of the active metabolite 2 have been synthesized. Their in vivo biological activity determined in rat and mouse delayed type hypersensitivity has been found to correlate well with their in vitro DHODH potency. The most promising compound (3) has shown activity in rat and mouse collagen (II)-induced arthritis models (ED50 = 2 and 31 mg/kg, respectively) and has shown a shorter half-life in man when compared with leflunomide. Clinical studies in rheumatoid arthritis are in progress.
