A novel (5E,9Z)-dialkylindolizidine from the ant Monomorium smithii.

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.

Chemotaxonomic implications of the venom chemistry of someMonomorium "antarcticum" populations.

A comparative analysis of the venom alkaloids produced by ants in the genusMonomorium (= Chelaner) collected on North Island and South Island, New Zealand, has been undertaken. All of the ants producetrans-2, 5-dialkylpyrrolidines along with 3,5-dialkylpyrrolizidines. The structures and sterochemistry of the novel alkaloidstrans-2-butyl-5-(8-nonenyl) pyrrolidine, (5E,8Z)-3,5-di(5-hexenyl)pyrrolizidine, and (5Z,8E)-3-methyl-5-(8-nonenyl)pyrrolizidine were established by unambiguous synthesis. The geographic distribution and the chemotaxonomic significance of the alkaloids produced by these ants are discussed.

Volatile compounds from ponerine ants in the genusMesoponera.

Volatile constituents have been characterized from two species of ponerine ants in the genusMesoponera. 2,5-Dimethyl-3-isopentyl-pyrazine has been identified from cephalic extracts ofM. castanea andM. castaneicolor, by gas chromatography-mass spectrometry. Combined gasters and thoraces of both species are also characterized by the presence of nonanal, nonanoic acid, isovaleric acid, phenylacetic acid, and undecanal, as well as a series of aliphatic amines and amides.N-Isoamylnonylamine was a major constituent that was accompanied byN-isoamylnonenylamine,N,N-diisoamylnonylamine,N-acetyl nonylamine,N-formyl isoamylnonylamine,N-isovaleroyl nonylamine, and several other secondary and tertiary amines. The possible significance of the amines and amides as idiosyncratic natural products ofMesoponera species is discussed.