23996-36-3Relevant articles and documents
I2-Mediated transition-metal-free aromatic C-H amination for the synthesis of benzimidazol-2-ones and related heterocycles
Meng, Yinggao,Wang, Bingnan,Ren, Linning,Zhao, Qiongli,Yu, Wenquan,Chang, Junbiao
, p. 13790 - 13796 (2018/08/21)
A practical iodine-mediated direct aromatic C-H amination reaction has been established for benzimidazol-2-one synthesis under transition-metal-free conditions. The required 1,3-diarylurea substrates are readily accessible by the addition of N-substituted arylamines to the corresponding isocyanates. This versatile and operationally simple synthetic process is broadly applicable to a wide range of 1,3-diarylureas and provides facile access to benzimidazol-2-ones and related heterocycles. Moreover, the present C-H amination reaction can also be performed directly from disubstituted amines and isocyanates without the purification of the urea intermediates in a scalable fashion.
Selective: S -arylation of 2-oxazolidinethiones and selective N -arylation of 2-benzoxazolinones/2-benzimidazolinones
Sun, Chu-Han,Lu, Yi,Zhang, Qing,Lu, Rong,Bao, Lin-Qing,Shen, Mei-Hua,Xu, Hua-Dong
, p. 4058 - 4063 (2017/07/10)
There exist three possible patterns for the reaction of cyclic 2-oxazolidinethione and 2-benzoxazolidinethione with arynes, namely (a) S-arylation, (b) N-arylation, and (c) aryne insertion into the thiocarbonyl group (CS). Our studies demonstrate that S-arylation wins out affording S-aryl dihydrooxazoles. In contrast, for related reactions of cyclic 2-benzoxazolinone and 2-benzimidazolinone with arynes, it is found that N-arylation outcompetes O-arylation and aryne insertion into the CO group to give N-aryl 2-benzoxazolinones and N-aryl 2-benzimidazolinones.
Pd(II)/Ag(I)-Promoted One-Pot Synthesis of Cyclic Ureas from (Hetero)Aromatic Amines and Isocyanates
Youn, So Won,Kim, Yi Hyun
, p. 6140 - 6143 (2016/12/09)
A simple and facile one-pot reaction has been developed to afford a diverse range of N,N′-disubstituted benzimidazolones and imidazopyridinones containing two differently substituted N atoms. A cooperative Pd(II)/Ag(I) system promotes the sequential addition/intramolecular C-H amidation reaction of (hetero)aromatic amines and isocyanates, leading to the formation of two C-N bonds. A mechanism involving radical intermediates generated by single-electron transfer (SET) in the presence of a Ag2CO3 oxidant and Pd(OAc)2 Lewis acid is proposed. This protocol offers an operationally easy, simple, and robust approach with the use of readily available starting materials, good functional group tolerance, and high efficiency.