Achieving functional group diversity in parallel synthesis: solution-phase synthesis of a library of ureas, carbamates, thiocarbamates, and amides using carbamoylimidazolium salts
作者:Justyna A. Grzyb、Robert A. Batey
DOI:10.1016/j.tetlet.2008.06.096
日期:2008.9
A convenient protocol for the parallelsolution-phasesynthesis of a library of thiocarbamates, ureas, carbamates, and amides from carbamoylimidazolium salts has been developed. The crystalline carbamoylimidazolium salts are readily synthesized from secondary amines, CDI and iodomethane, and act as stable carbamoylation reagents. A common set of reaction conditions and a straightforward non-chromatographic
A Simple Method for the Preparation of Di-, Tri- and Tetrasubstituted Non-Symmetrical Ureas
作者:Nicholas C. Tomkinson、Eve Bridgeman
DOI:10.1055/s-2005-923584
日期:——
The synthesis of a series of di-, tri- and tetrasubstituted non-symmetrical ureas is described. Di- and trisubstituted ureas are prepared in excellent yield by treatment of a phenyl carbamate in a self-tunable single-mode microwave synthesizer with a primary or secondary amine. The synthetically more challenging tetrasubstituted urea can be prepared using the 4-nitrophenyl carbamate and a secondary amine.
Novel iminium-type coupling agents containing proton acceptors in their iminium moiety, which can be used beneficially as coupling agents in various chemical polypeptide and/or polynucleotide syntheses, and are particularly useful as yield enhancing and racemization suppressing coupling agents for use in peptide syntheses, are disclosed. Further disclosed are a process of preparing such iminium-type coupling agents and their use in the preparation of polypeptides and/or polynucleotides.