Syntheses of heterocyclic compounds. Part XVIII. Aminolysis of 3-aryl-4-bromosydnones, and acid hydrolysis of 3-arylsydnoneimines
作者:G. S. Puranik、H. Suschitzky
DOI:10.1039/j39670001006
日期:——
various 3-aryl- and 3-heteroaryl-4-bromosydnones with piperidine gives the corresponding piperidino-glycyl-piperidines. Fluorine labelling has confirmed the postulated course of fission induced by acids in 3-aryl-sydnoneimines.
method for constructing 1,4-pyrazoles from arylglycines was developed using the copper-catalyzed sydnone–alkyne cycloaddition reaction. The procedure offers a straightforward and general route to the pyrazole heterocycle through a three-step one-pot procedure.
Reactions of anilines with ethyl bromoacetate under microwave irradiation have afforded N-arylglycines that are subsequently converted to their N-nitroso derivatives with a combination of silica chloride or periodic acid, wet SiO2 and sodium nitrite in CH2Cl2 with satisfactory yields. In the final step, the use of 1,3-dibromo-5,5-dimethylhydantoin (DBH) as a new and effective reagent for dehydration of N-nitroso-N-arylglycines to sydnones was successfully examined.
Synthesis of 2<i>H</i>-Indazoles by the [3 + 2] Dipolar Cycloaddition of Sydnones with Arynes
作者:Yuesi Fang、Chunrui Wu、Richard C. Larock、Feng Shi
DOI:10.1021/jo201605v
日期:2011.11.4
A rapid and efficient synthesis of 2H-indazoles has been developed using a [3 + 2] dipolar cycloaddition of sydnones and arynes. A series of 2H-indazoles have been prepared in good to excellent yields this protocol, and subsequent Pd-catalyzed coupling reactions can be applied to the halogenated products to generate a structurally diverse library of indazoles.
Raman spectra of SiC nanorods with different excitation wavelengths
作者:Yan Yan、Fumin Huang、Shulin Zhang、Bangfen Zhu、Eryi Shang、Shoushan Fan
DOI:10.1007/bf02901158
日期:2001.11
With increasing excitation wavelength from 514 to 782 mn, a significant difference in the Raman spectra of SIC nanorods was observed as compared to bulk material. The intensity ratio of the LO mode to that of the IF mode increases with the excitation wavelength increasing. This has been identified as resonant Raman scattering caused by Frohlich interaction.