Potassium Fluoride on Alumina: Synthesis of O-Aryl N,N-Dimethylthiocarbamates and their Rearrangement into S-Aryl N,N-Dimethyl-Thiocarbamates Under Microwave Irradiation
摘要:
A series of O-aryl N,N-dimethyl thiocarbamates have been prepared by the reaction of dimethylthiocarbamoyl chloride with phenols absorbed on potassium fluoride on alumina. The rearrangement of O-aryl N,N-dimethylthiocarbamate into S-aryl N,N-dimethyl thiocarbamate under microwave irradiation was also studied. The use of conductive support like graphite or silicon carbide allow these rearrangements although the O-aryl N,N-dimethylthiocarbamates have very low dielectric lost.
Studies of the Thiocarbonyl Compounds. III. The Mechanism of the Thermal Rearrangement of Aryl Thionocarboxylates
作者:Aritsune Kaji、Yoshiaki Araki、Koshin Miyazaki
DOI:10.1246/bcsj.44.1393
日期:1971.5
The thermal rearrangement of aryl thionocarboxylates was kinetically investigated in diphenyl ether. The rate constants of the rearrangement of aryl N,N-dimethylthionocarbamates were well correlated with the σ− values, but the plots of the electron-releasing para-substituents deviated slightly on the lower side of the meta correlation line. A good linear free-energy relationship existed between the
new developments, a better understanding of the underlying principles is crucial. In this context, we have studied the Newman–Kwartrearrangement of O-arylthiocarbamates to the corresponding S-aryl derivatives, the key step in the synthesis of thiophenols from the corresponding phenols. This transformation is a particularly useful example because the conventional method requires temperatures up to 300 °C
The Newman-Kwart Rearrangement of<i>O</i>-Aryl Thiocarbamates: Substantial Reduction in Reaction Temperatures through Palladium Catalysis
作者:Jeremy N. Harvey、Jesús Jover、Guy C. Lloyd-Jones、Jonathan D. Moseley、Paul Murray、Joseph S. Renny
DOI:10.1002/anie.200903908
日期:2009.9.28
Newman–Kwart rearrangement allows an escape from the harsh thermal conditions of the standard uncatalyzed reaction (see scheme). Mechanistic investigations, employing kinetic, isotopic labelling (2H, 18O, 34S) and DFT studies, suggest that the reaction proceeds through a five‐centred Pd–S coordinated oxidative addition, with intermolecular exchange of aryl and thiocarbamate moieties through dimerization of the
The Newman−Kwart Rearrangement: A Microwave Kinetic Study
作者:John P. Gilday、Philip Lenden、Jonathan D. Moseley、Brian G. Cox
DOI:10.1021/jo702633g
日期:2008.4.1
The kinetic profile of the Newman−Kwart rearrangement has been evaluated using microwave heating. After first demonstrating equivalence between conventional convective heating and microwave heating, data was gathered and analyzed to determine the effects of substituent, solvent, and concentration on the reaction order. Reaction rate constants, Arrhenius constants, and activation energies have been