Preparation Of Tertiary Amides Research Articles

Synthesis of secondary and tertiary amides without coupling agents from amines and potassium acyltrifluoroborates (KATs).

Although highly effective for most amide syntheses, the activation of carboxylic acids requires the use of problematic coupling reagents and is often poorly suited for challenging cases such as N-methyl amino acids. As an alternative to both secondary and tertiary amides, we report their convenient synthesis by the rapid oxidation of trifluoroborate iminiums (TIMs). TIMs are easily prepared by acid-promoted condensation of potassium acyltrifluoroborates (KATs) and amines and are cleanly and rapidly oxidized to amides with hydrogen peroxide. The overall transformation can be conducted either as a one-pot procedure or via isolation of the TIM. The unique nature of the neutral, zwitterionic TIMs makes possible the preparation of tertiary amides via an iminium species that would not be accessible from other carbonyl derivatives and can be conducted in the presence of unprotected functional groups including acids, alcohols and thioethers. In preliminary studies, this approach was applied to the late-stage modifications of long peptides and the iterative synthesis of short, N-methylated peptides without the need for coupling agents.

ChemInform Abstract: Preparation of Tertiary Amides via Aryl, Heteroaryl, and Benzyl Organozinc Reagents: Scope and Limitations.

AbstractVarious (het)aryl‐ and benzylzinc halides react successfully with the carbamoyl chlorides (II) and (XIII).

Preparation of Tertiary Amides from Carbamoyl Chlorides and Organocuprates.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Preparation of tertiary amides from carbamoyl chlorides and organocuprates.

[reaction: see text] Reaction of carbamoyl chlorides with cyano-Gilman cuprates affords tertiary amides in good to excellent yields. The reaction is general due to the possibility of using reagents made either from organolithium or from Grignard compounds. The characterization of the main side products allowed for the suggestion of a possible mechanism.

A Convenient Preparation of Tertiary Amides from Carboxylic Acids

Abstract We wish to report a new method which effects the direct transformation of carboxylic acids to 3° amides under mild conditions. The procedure is operationally simple and yields of products are generally good. These features render it an attractive alternative to existing methods2.