A Novel (5E,9Z)-Dialkylindolizidine from the Ant Monomorium smithii

Abstract

The alkaloidal venom of Monomorium smithii was found to contain (5E,9Z)-3-butyl-5-(4-penten-1-yl)indolizidine [1b], a novel indolizidine, its monocyclic analogue trans-2-butyl-5-(8-nonen-1-yl)pyrrolidine [2], (5E,8Z)-3,5-di(5-hexen-1-yl)pyrrolizidine [3], and trans-2-(5-hexen-1-yl)-5-(8-nonen-1-yl)pyrrolidine [4]. The structure of 1b was based on the results of two independent syntheses. Reductive amination of the appropriate triketone confirmed the carbon-nitrogen skeleton of 1b and suggested its stereochemistry, which was verified by the results of a stereoselective synthesis based on pyrrole hydrogenation. The chemotaxonomic implications of this first report of the concomitance of a 3,5-dialkylindolizidine and a 3,5-dialkylpyrrolizidine in an ant venom are discussed.

Toxicity and utilization of chemical weapons: does toxicity and venom utilization contribute to the formation of species communities?

“…The differences we found in the venom composition of M. smithii compared to a previous study (Jones et al. 1990) are likely due to the possibility that there are two cryptic species, which are morphologically similar and given the current taxonomic keys, can only be identified to M. smithii . While it is a possibility that species with less toxic venom might simply deliver more of it, this was not tested in this study.…”

“…It should also be mentioned that the venom composition of M. smithii differed from venom alkaloids identified in a previous study (Jones et al. 1990). The structural formulae of the venom components are given in Figure1.…”

Navigating the mtDNAroad map out of the morphological maze: interpreting morphological variation in the diverseMonomorium rothsteini(Forel) complex (Hymenoptera:Formicidae)

“…King et al , ), and beyond morphology there are other characters that can be useful in delimiting cryptic species. Although not investigated here, venom chemistry has revealed utility in discriminating morphologically divergent colonies of M. ‘rothsteini’ (Andersen et al , ) and its potential as an effective taxonomic character for myrmicine ants more generally (Jones et al , ; Don & Jones, ; Don et al , ). Similarly, Seppa et al () found cuticular hydrocarbons to have a strong taxonomic signal in closely related Formica species.…”

Venom Alkaloid Chemistry of Australian Species of the Monomorium rothsteini Complex, with Particular Reference to Taxonomic Implications

“…Similarly, all available evidence suggests that the venom chemistry of each alkaloid-producing species of Monomorium has a qualitatively characteristic signature. For example, venoms from alkaloid-producing United States and African species are mixtures of 2,5-dialkylpyrrolidines, with different species differing consistently in the components, which vary in overall C-atom chain length, and the occurrence of terminal C¼C bonds in the side chains [5] [10]. Additionally, in the Monomorium antarcticum complex from New Zealand, a wider variety of C 17 and C 19 2,5-dialkylpyrrolidines are present with their bicyclic pyrrolizidine analogs, and the structural variations include the presence or absence of side-chain C¼C bonds and the position of cyclization in the analogous bicyclic compounds.…”

“…Additionally, most of the alkaloids here have the pyrrolidine ring near the end of the C-atom chain. A number of the 2-ethylpyrrolidines 1 -10 have been previously reported [2] [7] from species of Monomorium outside the rothsteini complex, while 11 and 12 are common to North American Monomorium [5], and 13 has been reported from Monomorium smithii [10]. Table 1) based on venom-alkaloid chemistry.…”