N-Carboxyanhydrides Directly from Amino Acids and Carbon Dioxide and their Tandem Reactions to Therapeutic Alkaloids

12 October 2022, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


We report on the preparation of synthetically versatile N-carboxyanhydrides (NCAs) directly from amino acids and CO2 using n-propylphosphonic anhydride. Most of the NCAs were isolated with >95% purity after simple workup, avoiding the need for tedious purification procedures typically required using conventional methods. Because the reagents and conditions employed are mild, tandem reactions with moisture-sensitive NCAs were carried out to transform them into the medicinally active alkaloids tryptanthrin and phaitanthrin A in one pot. A qualitative analysis revealed that our NCA synthesis approach is more green than conventional methods, which all directly or indirectly use the highly poisonous gas phosgene.


amino acid
carbon dioxide
tandem reactions

Supplementary materials

Supplementary Information
Experimental procedures, characterization data, reaction schemes


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