623-78-9Relevant articles and documents
Continuous Flow Synthesis of Urea-Containing Compound Libraries Based on the Piperidin-4-one Scaffold
Riesco-Domínguez, Alejandra,Blanco-Ania, Daniel,Rutjes, Floris P. J. T.
supporting information, p. 1312 - 1320 (2018/04/02)
The advantages of performing reactions in continuous flow vs. the classic batch processes render flow chemistry a suitable technique for library synthesis. Inspired by our recent work to create fluorine-containing nitrogen heterocycles and by the potentia
N-substituted carbamates syntheses with alkyl carbamates as carbonyl source over Ni-promoted Fe3O4 catalyst
Shang, Jianpeng,Guo, Xiaoguang,Shi, Feng,Ma, Yubo,Zhou, Feng,Deng, Youquan
scheme or table, p. 328 - 336 (2011/05/14)
A series of catalysts of magnetic iron oxide containing Ni with different nickel content were prepared with co-precipitation method and tested in the syntheses of N-substituted carbamates from various amines and alkyl carbamates. Under the optimized reaction conditions, various N-substituted carbamates were successfully synthesized with 90-98% isolated yield. The catalyst could be recovered based on the magnetic property of the catalyst and reused for five runs without deactivation. The catalysts were characterized with X-ray photoelectron spectroscopy, X-ray diffraction, temperature-programmed reduction, temperature-programmed desorption, and Moessbauer spectroscopy analyses. The results showed that the catalytic activity may be derived from the delicate synergy between Ni and Fe species resulted in specific basic sites. Quasi in situ FT-IR and isotopic tracer revealed that the formation of substituted urea was the key step and the N-substituted carbamate was formed via further alcoholysis of the substituted urea.
Specificity of DNA alkylation by 1-(2-chloroethyl)-3-alkyl-3- acyltriazenes depends on the structure of the acyl group: Kinetic and product studies
Smith,Schmidt,Czerwinski,Taneyhill,Snyder,Kline,Michejda,Smith Jr.
, p. 466 - 475 (2007/10/03)
The reactions of calf thymus DNA with ten 1-(2-chloroethyl)-3-alkyl-3- acyltriazenes of varying acyl side chain structure were studied alone, or in the presence of porcine liver esterase in pH 7.0 phosphate buffer. In several of the key triazenes, the acyl substituent contained a free carboxylic acid group. With esterase present in the reaction mixture, the resultant levels of DNA alkylation could be correlated with the kinetic rates of decomposition of the triazenes. Under these conditions, the predominant pathway of decomposition involved deacylation of the parent triazene and eventual production of an alkanediazonium ion. This intermediate subsequently alkylated DNA-guanine to give 7-alkylguanine as the principal reaction product. In the absence of esterase, the order of DNA alkylation for all of the acyltriazenes did not correlate with their respective rates of decomposition, leading to the conclusion that the triazenes did not decompose by the expected mode of uncatalyzed N(2)-N(3) heterolyic cleavage. The major DNA alkylation product from the N(3)-methyltriazenes was 7-methylguanine, instead of the expected 7-(chloroethyl)- and 7-(hydroxyethyl)guanine products, which suggested that the acyl group was being hydrolyzed. However, acyltriazenes with an N(3)-benzyl group rather than a methyl in this position produced very little 7-benzylguanine product, contrary to prediction. An alternative mechanism involving internally assisted hydrolysis of the side chain ester is proposed to explain these results. NMR product analysis and computational studies were carried out to lend support to the postulated mechanism.
