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Updated: May 20, 2026

Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
Published on: February 7, 2019
Synthesis and Biological Evaluation of Cremastrine and an Unnatural Analogue
Kristopher N Hahn1, Olugbeminiyi O Fadeyi, Hyekyung P Cho
1Department of Chemistry, Vanderbilt University, Nashville, TN 37232, USA.
Abstract:
In this Letter, we describe the first total synthesis of cremastrine, a pyrrolizidine alkaloid from Cremastra appendiculata, with anticholinergic activity as well as an unnatural analogue. The streamlined synthesis proceeds in 9 steps, 7 steps longest linear sequence, in 25.2% overall yield, and features novel methodology to construct the pyrrolizidine core. Biological evaluation of cremastrine and the unnatural analogue indicated that both are pan-mAChR functional antagonists.
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