16641-71-7Relevant articles and documents
Kinetics and mechanism of the aminolysis of phenyl and 4-nitrophenyl chloroformates in aqueous solution
Castro, Enrique A.,Ruiz, Maria G.,Salinas, Sandra,Santos, Jose G.
, p. 4817 - 4820 (1999)
The reactions of secondary alicyclic amines with phenyl and 4- nitrophenyl chloroformates (PClF and NPClF, respectively) are subjected to a kinetic investigation in aqueous solution, 25.0 °C, ionic strength 0.2 (KCl). The reactions are followed spectropho
A facile synthesis of sulfonylureas: Via water assisted preparation of carbamates
Tanwar, Dinesh Kumar,Ratan, Anjali,Gill, Manjinder Singh
, p. 4992 - 4999 (2017/07/11)
A novel and simple approach to the synthesis of sulfonylureas has been reported. It involved the reaction of various amines with diphenyl carbonate to yield the corresponding carbamates, which subsequently reacted with different sulphonamides to produce different sulfonylureas in excellent yields. The first reaction of diphenyl carbonate with amines was carried out in aqueous:organic (H2O:THF, 90:10) medium at room temperature to produce carbamates that paved a straightforward route to sulfonylureas after reaction with sulfonamides. The above process avoided traditional multistep protocols and the use of hazardous, irritant, toxic and moisture sensitive reagents such as phosgene, isocyanates and/or chloroformates.
Leaving-group substituent controls reactivity and reaction mechanism in aminolysis of phenyl y-substituted-phenyl carbonates
Kang, Ji-Sun,Song, Yoon-Ju,Um, Ik-Hwan
, p. 2023 - 2028 (2013/09/02)
A kinetic study is reported for the nucleophilic substitution reactions of phenyl Y-substituted-phenyl carbonates (5a-5k) with piperidine in 80 mol % H2O/20 mol % DMSO at 25.0 ± 0.1 °C. The plots of k obsd vs. [piperidine] for the reactions of substrates possessing a strong electron-withdrawing group (EWG) in the leaving group (i.e., 5a-5i) are linear and pass through the origin. In contrast, the plots for the reactions of substrates bearing a weak EWG or no substituent (i.e., 5j or 5k) curve upward, indicating that the electronic nature of the substituent Y in the leaving group governs the reaction mechanism. Thus, it has been suggested that the reactions of 5a-5i proceed through a stepwise mechanism with a zwitterionic tetrahedral intermediate (i.e., T±) while those of 5j and 5k proceed through a stepwise mechanism with two intermediates (i.e., T± and its deprotonated form T-). The slope of the Bronsted-type plot for the second-order rate constants (i.e., kN or Kk2) changes from -0.41 to -1.89 as the leaving-group basicity increases, indicating that a change in the rate-determining step (RDS) occurs. The reactions of 5a-5k with piperidine result in larger k1 values than the corresponding reactions with ethylamine. Copyright