Alkaloids from Dendrobatid Frogs: Structures of Two ω-Hydroxy Congeners of 3-Butyl-5-Propylindolizidine and Occurrence of 2,5-Disubstituted Pyrrolidines and a 2,6-Disubstituted Piperidine

Abstract

Forty alkaloids were detected and characterized from skin extracts of high- and low-elevation populations of the poison frog Dendrobates histrionicus from northwestern Colombia. Combined gc/ms with NH3 or ND3 in a chemical ionization mode detected protonated parent ions and determined the number of exchangeable NH and OH hydrogens. Six previously unknown dendrobatid alkaloids were characterized. Two were 2,5-disubstituted pyrrolidines, which included pyrrolidine 197B, a trans-2-butyl-5-pentylpyrrolidine, while a third was a 2,6-dipentylpiperidine. Indolizidines 239AB and 239CD had the same relative configuration as the parent alkaloid 223AB [(5E,9E)3-butyl-5-propylindolizidine] and contained, respectively, a omega-hydroxy group in the propyl or butyl side chain. The profiles of alkaloids in the new northern populations of D. histrionicus are typical of the species in containing a set of about eight histrionicotoxins, in marked contrast to a related species, Dendrobates lehmanni, which does not contain histrionicotoxins.

Crystal structure of 8-(2-methylphenyl)-11-[(E)-(2-methylphenyl)- methylidene]-14-hydroxy-3,13-diazaheptacyclo- [13.7.1.9,13.02,9.02,14.03,7.019,23]tetracosa-1(22),15,17,19(23),20-pentaen-10- one methanol monosolvate, C37H34N2O2-CH3OH, C38H38N2O3

“…Chemistry of azomethine ylides have gained significance, as it serves as an expedient route for the construction of nitrogen-containing heterocycles [1]. Acenaphthenequinone is av ersatile precursor for azomethine ylide cycloaddition as it reacts with various a-amino acids generating reactive 1,3-dipoles [2,3].The pyrrolizine substructure occurs in many natural products of potential use in medicine and agriculture [4].…”

Asymmetric Hydroamination and Reductive Amination in Total Synthesis

“…Synthesis of (þ)-pyrrolidine 197 B Pyrrolidine 197 B is an alkaloid isolated from skin extracts of high and low elevation populations of poisonous frog Dendrobates histrionicus. 36 These alkaloids show a wide spectrum of biological activity 37 including most importantly antibiotic and hemolytic property. But the biological properties of most members of this family remain anonymous as they are isolated from the natural source in very small Synthesis of (þ)-Xenovenine Another alkaloid (þ)-xenovenine has been found in the cryptic thief ant Solenopsis xenoveninum.…”

New Diastereoselective Route to 2‐Substituted cis‐(2S,5S)‐ and trans‐(2S,5R)‐5‐Alkylpyrrolidines as Indolizidine and Pyrrolizidine Scaffolds

“…[3] Of the examples shown in Figure 1, the 3,5-dialkylindolizidine monomorine I (1) is a trail pheromone of the Pharaoh ant Monomorium pharaonis L., [4] whereas indolizidine (Ϫ)-223AB (2) is a constituent of the poison frog Dendrobates histrionicus. [5] Notably, its less widespread cis-3,5-dialkylated analogue 3 has been isolated both from amphibians and from the Solenopsis Diplorhoptrum worker ant. [6] Pyrrolizidine alkaloids such as (Ϫ)-xenovenine (4) have been found in the venom Figure 1.…”