Expeditious routes to 4-alkoxyquinazoline-2-carbonitriles and thiocarbamates via N-arylimino-1,2,3-dithiazoles using microwave irradiation
作者:Thierry Besson、Marie-Joëlle Dozias、Jérôme Guillard、Patrick Jacquault、Marie-Dominique Legoy、Charles W. Rees
DOI:10.1016/s0040-4020(98)00276-2
日期:1998.6
Conversion of N-arylimino-4-chloro-5H-1,2,3-dithiazole 11 into the 4-alkoxyquinazoline-2-carbonitriles 13a-i and of the aryl isothiocyanates 15 into aryl thiocarbamates 16a-j with sodium alkoxides in the corresponding alcohol, either by conventional thermolysis or by microwave irradiation are described and directly compared. Microwave irradiation of the solutions in open vessels in a monomode system with focused irradiation and continuous temperature control (Synthewave S402 reactor) usually gave cleaner, faster and higher yielding reactions. These reactions could be safely and beneficially scaled up to multigram quantities in a larger reactor (Synthewave S1000). (C) 1998 Elsevier Science Ltd. All rights reserved.
An Fe<sub>3</sub>O<sub>4</sub>@SiO<sub>2</sub>/Schiff base/Cu(<scp>ii</scp>) complex as an efficient recyclable magnetic nanocatalyst for selective mono <i>N</i>-arylation of primary <i>O</i>-alkyl thiocarbamates and primary <i>O</i>-alkyl carbamates with aryl halides and arylboronic acids
the selective mono N-arylation of primary O-alkyl thiocarbamates and primary O-alkyl carbamates with aryl halides and arylboronic acids in the presence of a recyclable magnetic Cu(II) nanocatalyst is described. A variety of mono N-arylated O-alkyl thiocarbamates and O-alkyl carbamates were prepared in good to excellent yields with a broad range of aryl coupling partners. The magnetic nanocatalyst can