1849-01-0Relevant articles and documents
Carbonylation of o-phenylenediamine and o-aminophenol with dimethyl carbonate using lead compounds as catalysts
Fu, Yue,Baba, Toshihide,Ono, Yoshio
, p. 91 - 97 (2001)
Lead compounds are active catalysts for carbonylation and carbonylation/methylation of o-phenylenediamine and o-aminophenol with dimethyl carbonate (DMC). 2-Benzimidazolone was obtained in 84% yield by the reaction of o-phenylenediamine with DMC for 1 h at 443 K in the presence of Pb(NO3)2. In the presence of Pb(OAc)2, the reaction quantitatively gave 1,3-dimethyl-2-benzimidazolone, which was formed by methylation of the primary product, 2-benzimidazolone, at 473 K. The effects of reaction variables on the yields of 2-benzimidazolone and 1,3-dimethyl-2-benzimidazolone were examined. The reaction of o-aminophenol with DMC selectively gave a carbonylation product, 2-benzoxazolone, or a carbonylation/methylation product, 3-methyl-2-benzoxazolone, depending on the reaction conditions in the presence of Pb(OAc)2.
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Popov et al.
, (1976)
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Study of unsaturated azoles. 16 Synthesis and reactions of 2-styrylbenzimidazoles
Popov
, p. 949 - 953 (1997)
Fusion of 1-methyl-2-styrylbenzimidazole with KOH leads to separation of the phenylvinyl or the N-methyl group to give 1-methylbenzimidazol-2-one or 2-styrylbenzimidazole in the ratio 1:1. Decomposition of the perbromides of benzimidazoles by heating in water gives 5(6)-bromobenzimidazoles and, in the presence of KI, to 5(6)-iodobenzimidazoles. Methods are presented for the synthesis of 5(6)-bromo- and 5(6)-iodo-2-styryl- and also 2-α-bromo- and 2-α-iodostyrylbenzimidazoles. 1998 Plenum Publishing Corporation.
Iron-Catalyzed Intramolecular C—H Amidation of N-Benzoyloxyureas
Zhong, Dayou,Wu, Lin-Yang,Wang, Xing-Zhen,Liu, Wen-Bo
, p. 855 - 858 (2021/02/16)
A redox-neutral Fe-catalyzed intramolecular C—H amidation of N-benzoyloxyureas is described. This methodology employs a simple iron complex in situ generated from Fe(OTf)2 and bipyridine as the catalyst and N-benzoyloxyureas as the nitrene prec
Methylenation for Aldehydes and Ketones Using 1-Methylbenzimidazol-2-yl Methyl Sulfone
Ando, Kaori,Oguchi, Mai,Kobayashi, Takahisa,Asano, Haruka,Uchida, Nariaki
, p. 9936 - 9943 (2020/09/04)
The methylenation reagent 1-methylbenzimidazol-2-yl methyl sulfone 2 reacts with various aldehydes and ketones in the presence of t-BuOK (room temperature, 1 h) in dimethylformamide to give the corresponding terminal alkenes generally in high yields. For sensitive substrates, the reaction is better carried out at low temperature using sodium hexamethyldisilazide in 1,2-dimethoxyethane. The byproduct is easily removed from the products, and the reaction conditions are mild and practical. Reagent 2 can be easily prepared from commercially available 2-mercaptobenzimidazole 5 in 95% yield without any expensive reagents.