- Transition Metal-Free Carbazole Synthesis from Arylureas and Cyclohexanones
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An efficient strategy for carbazole synthesis from arylureas and cyclohexanones under transition metal-free conditions has been developed. The combined use of potassium iodide and iodine could significantly improve the reaction efficiency to provide 2,6-disubstituted 9-arylcarbazoles in moderate to good yields. In this kind of transformation, the whole carbazole moiety (except the nitrogen atom) comes from two equivalents of cyclohexanones. (Figure presented.).
- Wu, Jun,Xie, Yanjun,Chen, Xiangui,Deng, Guo-Jun
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supporting information
p. 3206 - 3211
(2016/10/21)
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- Copper-catalyzed mild nitration of protected anilines
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A practical copper-catalyzed direct nitration of protected anilines, by using one equivalent of nitric acid as the nitrating agent, has been developed. This procedure features mild reaction conditions, wide structural scope (with regard to both N-protecting group and arene substitution), and high functional-group tolerance. Dinitration with two equivalents of nitric acid is also feasible. Practical and reliable: A Cu-catalyzed selective nitration of para- and ortho-substituted aniline derivatives by using one equivalent of HNO3 has been developed that produces water as the only stoichiometric byproduct (see scheme; PG=protecting group). This method is compatible with strongly electron-deficient substrates, enabling dinitration (by using 2.0 equiv of HNO3). This method allows for a rapid access to relevant nitrogen-containing heterocyclic architectures.
- Hernando, Elier,Castillo, Rafael R.,Rodríguez, Nuria,G?mez Arrayás, Ram?n,Carretero, Juan C.
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supporting information
p. 13854 - 13859
(2016/02/18)
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- A Facile and High-yielding Preparation of 1-Aryl-3,3-dialkylureas
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A convenient procedure for the preparation of 1-aryl-3,3-dialkylureas using bis(trichoromethyl) carbonate ('triphosgene') is described.
- Xian, Ming,Lu, Jianming,Zhu, Xiaoqing,Mu, Linjing,Cheng, Jin-Pei
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p. 442 - 443
(2007/10/03)
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- INFRARED SPECTROSCOPIC AND CONFORMATIONAL STUDIES OF TRISUBSTITUTED UREAS CONTAINING CHLOROPHENYL GROUPS
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The IR spectra, in the ν(N-H) region, of trisubstituted ureas R2UPhCl and RPhUPhCl containing a chlorophenyl group have been studied in order to examine the effects of the introduced chlorine atom.The out-trans-cis isomerism about the NH-CO rotational axis is discussed in reation to steric effect of the R2 group, Ph-Ph interaction and inter- and intra-molecular hydrogen bonding.In dilute solution, R2UPhCl exists in the trans or the out form, and RPhUPhCl in the cis form. o-Chlorophenyl derivatives show a monomeric ν(N-H) band at a wavenumber lower than that of the other derivatives and no associated ν(N-H) bands in concentrated or even in saturated solutions.Some of the derivatives are found to be in the same form in the solid state as in solution due to the retention of intra-molecular NH...Cl hydrogen bonding.
- Mido, Yoshiyuki,Furusawa, Chizuko
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