617-22-1Relevant articles and documents
Visible-Light-Promoted Diboron-Mediated Transfer Hydrogenation of Azobenzenes to Hydrazobenzenes
Song, Menghui,Zhou, Hongyan,Wang, Ganggang,Ma, Ben,Jiang, Yajing,Yang, Jingya,Huo, Congde,Wang, Xi-Cun
, p. 4804 - 4811 (2021/04/06)
A visible-light-promoted transfer hydrogenation of azobenzenes has been developed. In the presence of B2pin2 and upon visible-light irradiation, the reactions proceeded smoothly in methanol at ambient temperature. The azobenzenes with diverse functional groups have been reduced to the corresponding hydrazobenzenes with a yield of up to 96%. Preliminary mechanistic studies indicated that the hydrogen atom comes from the solvent and the transformation is achieved through a radical pathway.
Visible-light-promoted decarboxylative addition cyclization of: N -aryl glycines and azobenzenes to access 1,2,4-triazolidines
Ma, Ben,Qi, Yanfang,Song, Menghui,Wang, Xi-Cun,Yang, Jingya,Zhou, Hongyan
supporting information, p. 5806 - 5811 (2021/08/23)
Methods for the synthesis of 1,2,4-triazolidines are scarce. Herein, we report a visible-light-promoted decarboxylative addition cyclization of N-aryl glycines and azobenzenes to access such important compounds. Using commercially available methylene blue (MB) as an organic photocatalyst, the reaction proceeded smoothly in the absence of transition-metal catalysts at ambient temperature, affording the corresponding products, 1,2,4-triaryl 1,2,4-triazolidines, in good to excellent yields. This work demonstrates a new synthetic application of readily available azobenenes and provides a novel strategy for constructing 1,2,4-triazolidines.
Novel o-Toluidine Metabolite in Rat Urine Associated with Urinary Bladder Carcinogenesis
Tajima, Yuya,Toyoda, Takeshi,Hirayama, Yuichiro,Matsushita, Kohei,Yamada, Takanori,Ogawa, Kumiko,Watanabe, Kenji,Takamura-Enya, Takeji,Totsuka, Yukari,Wakabayashi, Keiji,Miyoshi, Noriyuki
, p. 1907 - 1914 (2020/08/14)
o-Toluidine (o-Tol), a monocyclic aromatic amine, causes bladder cancer in humans and experimental animals and is therefore classified as a Group 1 carcinogen (IARC) in which the carcinogenicity of o-Tol is involved in metabolic activation, DNA damage, and DNA adduct formation. In the DNA adduct formation mechanism, o-Tol is metabolized by N-hydroxylation, N-acetoxylation, and then deacetoxylation to produce an electrophilic nitrenium ion, which is able to bind to a DNA base, such as dG-C8. Therefore, dG-C8-o-Tol is thought to be a plausible DNA adduct of o-Tol exposure. However, direct detection of dG-C8-o-Tol in biological samples has not been reported yet. Here, we show that a novel o-Tol metabolite, 2-methyl-N1-(2-methylphenyl)benzene-1,4-diamine (MMBD), a dimer by head-to-tail binding, was identified for the first time in o-Tol-exposed rat urine. MMBD was also detected in a reaction of o-Tol and S9 mix, indicating the formation was catalyzed by an enzymatic reaction. Moreover, MMBD showed a potent stronger mutagenicity in N-acetyltransferase overexpressed Salmonella typhimurium strains,and cytotoxicity in human bladder carcinoma T24 cells and human spleen lymphoblastoid TK6 cells compared with o-Tol. Furthermore, a DNA adduct (m/z 478.1) corresponding to dG-MMBD was detected in the reaction of calf thymus DNA with rat urine containing MMBD, and also in hepatic DNA of rats treated with o-Tol. These results therefore suggested that o-Tol-induced bladder carcinogenesis could be at least partly attributed to MMBD formation. The possible dimerization of monocyclic aromatic amines should be considered in the evaluation of the risk of bladder carcinogenesis after exposure.
