6940-23-4Relevant articles and documents
Pd/C-catalyzed reductive carbonylation of nitroaromatics for the synthesis of unsymmetrical ureas: One-step synthesis of neburon
Li, Chong-Liang,Peng, Jin-Bao,Qi, Xinxin,Ying, Jun,Wu, Xiao-Feng
supporting information, p. 12472 - 12475 (2018/08/04)
A Pd/C catalyzed reductive carbonylation of nitroarenes for the synthesis of unsymmetrical ureas has been developed. Using inexpensive and stable nitroarenes as the substrates, a series of unsymmetrical ureas were produced in moderate to good yields. A range of functional groups including thioethers, halides and vinyl were compatible with this reaction. As a heterogeneous catalyst, Pd/C was recycled and reused four times without losing activity. Notably, urea-based herbicide neburon was prepared in 64% yield under our standard conditions.
Synthesis of unsymmetrical ureas by sulfur-assisted carbonylation with carbon monoxide and oxidation with molecular oxygen under mild conditions
Mizuno, Takumi,Nakai, Takeo,Mihara, Masatoshi
experimental part, p. 2492 - 2496 (2009/12/08)
With ambient pressure of carbon monoxide and oxygen at room temperature, N,N-dialkyl-N′-arylureas were selectively accessible from secondary amines, aromatic amines, and sulfur in good to excellent yields. For example, N-butyl-N-methyl-N′-(3,4-dichlorophenyl)urea, which is used as a herbicide (neburon), was afforded successfully from butylmethylamine (2 equiv), 3,4-dichloroaniline (1 equiv) and sulfur (1 equiv) in 79% (21.8 g) yield using carbon monoxide (0.1 MPa) and oxygen (0.1 MPa) at 20°C in DMF. Georg Thieme Verlag Stuttgart.
