Structural Elucidation using Highly Sensitive Labeling Reagents and Total Synthesis of Amoxetamide A, a New Anoikis Inducer

Amoxetamide A is a new anoikis inducer identified in the combined-culture broth of Amycolatopsis sp. 26-4 and Tsukamurella pulmonis TP-B0596. Although its planar structure has been determined through extensive NMR studies, its stereochemical structure remains to be elucidated due to the limited amounts of available samples. Herein, we report its stereochemical determination using our original labeling reagents and chemical synthesis, which was realized by consuming trace amount (ca 10 μg) of natural sample. Moreover, the total synthesis of amoxetamide A is reported. Undesired intramolecular cyclization of an intermediate accelerated by the Thorpe-Ingold effect was completely avoided by using acyl sulfonamide as a protecting group of carboxylic acid. This first total synthesis of amoxetamide A enabled the confirmation of its stereochemistry and anoikis inducing activity.