Niobium Pentachloride Promoted Conversion of Carboxylic Acids to Carboxamides: Synthesis of the 4-Aryl-1,2,3,4-tetrahydroisoquinoline Alkaloid Structures
作者:Claudio C. Lopes、Rosangela S. Lopes、Marcelo S. Nery、Renata P. Ribeiro
DOI:10.1055/s-2003-36823
日期:——
A practical method for the conversion of carboxylic acids to the corresponding carboxamides mediated by niobium pentachloride under mild conditions is described. The synthesis of the 4-aryl-1,2,3,4-tetrahydroisoquinoline alkaloid structures was accomplished via benzylic lithiation of N-methyl-3,4-dimethoxy-2-(4'-methoxybenzyl)benzamide.
Repurposing the 3‐Isocyanobutanoic Acid Adenylation Enzyme SfaB for Versatile Amidation and Thioesterification
作者:Mengyi Zhu、Lijuan Wang、Jing He
DOI:10.1002/anie.202010042
日期:2021.1.25
molecules with novel skeletons, but also to identify the enzymes that catalyze diverse chemical reactions. Exploring the substrate promiscuity and catalytic mechanism of those biosynthetic enzymes facilitates the development of potential biocatalysts. SfaB is an acyladenylate‐forming enzyme that adenylates a unique building block, 3‐isocyanobutanoic acid, in the biosynthetic pathway of the diisonitrile
This work describes acylation reactions facilitated by a type of heterocycle‐based acyl transfer agent, 2‐acyloxypyridazinone. Reactions of 2‐acyloxypyridazinone with carboxylic acids yield mixed carbonic anhydride intermediates, which are reactive and could be coupled with a wide range of substrates including acids, amines, alcohols, and thiols. The wide substrate scope, ease of operation (no additive
The ubiquitousness of esters and amide functionalities makes their coupling reaction one of the most sought-after organic transformations. Herein, we have described an efficient microwave-assisted synthesis of esters and amides. Soluble triphenylphosphine, in conjugation with molecular iodine, gave the desired products without the requirement for a base/catalyst. In addition, a solid-phase synthetic