Remarkable effect of nitrogen dioxide for N-hydroxyphthalimide-catalyzed aerobic oxidation of methylquinolines.
Aerobic oxidation of methylquinolines was successfully achieved by the use of N-hydroxyphthalimide/Co(OAc)2/Mn(OAc)2 as catalyst in the presence of a small amount of nitrogen dioxide as an initiator.
A metal-free aerobic oxidation of nitrotoluenes catalyzed by N,N',N″-trihydroxyisocyanuric acid (THICA) and a novel approach to the catalyst.
A metal-free catalytic system with N,N',N″-trihydroxyisocyanuric acid (THICA) as the catalyst for the oxidation of nitrotoluenes is introduced, and a novel Pd-free approach for the synthesis of THICA was developed. In a solution of acetic acid, THICA and concentrated nitric acid, nitrotoluenes especially polynitrotoluenes such as 2,4,6-trinitrotoluene (TNT), were converted into the desired carboxylic acids under 0.2 MPa of O(2) at 100°C with yields up to 99%. THICA was synthesized from N-hydroxyphtalimide through a four-step synthesis in a total yield of 46%. A possible mechanism of this catalytic process was proposed where NO(2) and nitric acid first induced a radical of THICA, which then abstracts a hydrogen atom from the methyl on the aromatic ring to form a benzyl radical. This radical then initiates subsequent reactions. The production of the benzyl radical was supported by ESR measurements.
Bicyclic pyrazolidinone antibacterial agents. Synthesis of side chain analogues of carbapenems PS-5 and thienamycin
Abstract Bicyclic pyrazolidinone analogues of carbapenems, bearing either an ethyl or hydroxyethyl side chain at C-7, were prepared via the 1,3-dipolar cycloaddition chemistry of pyrazolidinium ylides.