Related Experiment Video
Updated: Jul 3, 2026

A Direct, Early Stage Guanidinylation Protocol for the Synthesis of Complex Aminoguanidine-containing Natural Products
Published on: September 9, 2016
Cytotoxic calanquinone A from Calanthe arisanensis and its first total synthesis
Chia-Lin Lee1, Kyoko Nakagawa-Goto, Donglei Yu
1Natural Products Research Laboratories, School of Pharmacy, University of North Carolina at Chapel Hill, 315 Beard Hall, CB# 7360, NC 27599-7360, USA.
Abstract:
Calanquinone A (1) was isolated from an EtOAc-soluble extract of Calanthe arisanensis through bioassay-guided fractionation. Its structure was identified by spectroscopic methods. Compound 1 showed potent cytotoxicity (EC(50)<0.5microg/mL) against lung (A549), prostate (PC-3 and DU145), colon (HCT-8), breast (MCF7), nasopharyngeal (KB), and vincristine-resistant nasopharyngeal (KB-VIN) cancer cell lines, and interestingly, showed an improved drug resistance profile compared to paclitaxel. The total synthesis of 1 was also achieved and is reported herein.
Related Concept Videos
Aldehydes and Ketones with HCN: Cyanohydrin Formation Overview
Alkylation of β-Diester Enolates: Malonic Ester Synthesis
Preparation of Alkynes: Dehydrohalogenation
Alkynes can be prepared by dehydrohalogenation of vicinal or geminal dihalides in the presence of a strong base like sodium amide in liquid ammonia. The reaction proceeds with the loss of two equivalents of hydrogen halide (HX) via two successive E2 elimination reactions.
