Carbamoylimidazolium and thiocarbamoylimidazolium salts: novel reagents for the synthesis of ureas, thioureas, carbamates, thiocarbamates and amides
作者:Justyna A. Grzyb、Ming Shen、Chiaki Yoshina-Ishii、W. Chi、R.Stanley Brown、Robert A. Batey
DOI:10.1016/j.tet.2005.05.056
日期:2005.7
Carbamoylimidazolium salts act as efficient N,N-disubstituted carbamoylating reagents. These salts are readily prepared by the sequential treatment of secondary amines with N,N′-carbonyldiimidazole (CDI) and iodomethane. The carbamoylimidazolium salts are more efficient carbamoyl transfer reagents than the intermediate carbamoylimidazoles, as a result of the ‘imidazolium’ effect. Kinetic studies on
A Photochemical Protocol for the Synthesis of Weinreb and Morpholine Amides from Carboxylic Acids
作者:Asimina Bourboula、Olga G. Mountanea、George Krasakis、Christiana Mantzourani、Maroula G. Kokotou、Christoforos G. Kokotos、George Kokotos
DOI:10.1002/ejoc.202300008
日期:——
A photochemical protocol for the synthesis of Weinreb amides and morpholine amides fromcarboxylicacids is presented. Various carboxylicacids were directly coupled to N,O-dimethylhydroxylamine and morpholine, upon irradiation with either LED 370 nm or sunlight in the presence of 4-dimethylaminopyridine and bromotrichloromethane, providing amides in moderate to high yields.
A new method for the synthesis of N-protected alpha-amino aldehydes was developed. N-Protected alpha-amino amides of morpholine were easily prepared and then reduced with LiAlH4 to produce clean N-protected alpha-amino aldehydes. This new scheme of synthesis can be used with Boc, Z and Fmoc amino-protecting groups. (C) 1999 Elsevier Science Ltd. All rights reserved.